RP-2 Radiation and Contamination

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Radiation Protection Radiation and Contamination

TABLE OF CONTENTS

INTRODUCTION 2 OBJECTIVES 3 1.0 STATION RADIATION SOURCES 5 1.1 PLANT RADIATION SOURCE PRODUCTION 5 1.2 FISSION PRODUCT ACTIVITY 5 1.3 ACTIVATED CORROSION PRODUCTS 7 1.4 ACTIVATED WATER AND IMPURITIES 8 2.0 PROTECTION AGAINST CONTAMINATION 9 2.1 PLANT DESIGN FEATURES 10 2.2 PLANT PROCEDURES 11 2.3 USE OF POSTING OR STATUS BOARDS 12 2.4 COMMON SENSE RULES AGAINST CONTAMINATION 12 3.0 RESPIRATORY PROTECTION 13 3.1 PROTECTION FACTORS 14 3.2 AIR-PURIFYING RESPIRATORS 15 3.3 ATMOSPHERE SUPPLYING RESPIRATORS 20 3.4 ESTABLISHING A RESPIRATOR PROGRAM 23 4.0 PROTECTIVE CLOTHING 25 4.1 DONNING PROTECTIVE CLOTHING 25 4.2 REMOVING PROTECTIVE CLOTHING 27 5.0 PERSONNEL CONTAMINATION ASSESSMENT 27 5.1 PERSONNEL DECONTAMINATION 28 5.2 AREA DECONTAMINATION 28 6.0 CONTROLLED AREA ACCESS CONTROL 28 6.1 COMMON SENSE RULES 29 7.0 SUMMARY 29

Chapter RP-2

Radiation Protection R A D I A T I O N A N D C O N T A M I N A T I O N C H A P T E R R P - 2

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INTRODUCTION Many millions of dollars are spent each year by nuclear utilities to minimize or reduce radiation and contamination. This money may be spent to employ radiation protection technicians, decontamination crews, or acquire specialized types of handling equipment. All have the task of controlling the spread of contamination. In this lesson on Radiation and Contamination, it is important for the radiation protection technician to understand the sources of radiation and contamination, their origin, and relative hazard based on energy. Protection from radiation exposure uses rather simple techniques: time, distance, and shielding. Contamination control is quite different, and much more involved. Engineering controls, contamination control systems, and protective equipment are all used to control the spread of contamination and ensure that we do not ingest or inhale radioactive material. In the final analysis, contamination control is designed to keep us from ingesting or inhaling radioactive material and preventing its inadvertent release to the environment. How then do we protect ourselves and others from radiation and contamination?


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OBJECTIVES TERMINAL OBJECTIVE The Contractor Radiation Protection Technician will describe the sources of radiation in the nuclear power plant including their means of production and their methods of removal. The Contractor Radiation Protection Technician will describe contamination control practices including the processes of isolating, surveying, and decontaminating areas, tools, and personnel. ENABLING OBJECTIVES Upon completion of this lesson, the Contractor Radiation Protection Technician will be able to:

1. List two (2) categories of plant radiation source production.

2. Describe mechanisms that allow fission products to be introduced into plant systems.

3. Explain the reason for monitoring fission product activity in the coolant.

4. Identify the common fission products.

5. Recognize the methods of removal or escape of halogens, noble gases, and soluble metal ions from the reactor coolant.

6. Identify activated corrosion products found in a light water reactor.

7. Describe the radiological impact of the use of stellite bearing surfaces on a primary system component.

8. Identify sources of activity in a Boiling Water Reactor (BWR) steam line during operation.

9. Identify contributor(s) to Pressurized Water Reactor, reactor coolant liquid activity and its production reaction.

10. Identify the reactor coolant gaseous activity contributors and their effect of post shutdown dose rate.

11. Specify when respiratory protection programs are governed by the NRC rather than OSHA.

12. Describe the concept of an atmosphere that is "Immediately Dangerous to Life and Health" (IDLH).

13. Compare the construction and operation of a negative pressure and positive pressure air-purifying respirator.


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14. Describe the processes by which particulates and iodines are removed by an air-purifying respirator.

15. List the factors, which affect the ability of a sorbent to adsorb iodine.

16. List limitations on the use of air-purifying respirators.

17. Compare the operation of continuous flow, demand, and pressure demand airline respirators.

18. List limitations on the use of air-line respirators.

19. Describe how protection factors are used in determining the proper respirator for a job.

20. Recall respirator protection factors listed in Appendix A of 10CFR20.

21. List, in general, potential sources of contamination.

22. List methods used to control exposure to airborne radioactivity.

23. List methods used to control contaminated areas.

24. Describe general practices for isolating, posting, and allowing entry to contaminated areas.

25. List radiological reasons for decontamination.


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1.0 STATION RADIATION SOURCES 1.1 PLANT RADIATION SOURCE PRODUCTION Ideally, during the course of normal operation, there would be no radiation sources other than the reactor. Fission products that are generated would be contained within the fuel cladding. However, mechanisms that allow fission products to be introduced into plant systems are fuel cladding defects, recoil and diffusion. This results in contamination of the reactor coolant by fission products leaking or diffusing through the cladding of fuel rods and the dissolution of activated corrosion products in the coolant. This as we know, is not the real world. Fuel is not perfect and some leakage of some fission products from the fuel can be anticipated during the lifetime of the core. Additionally, the cladding or fuel rods used to seal the fuel pellets will contain minute traces of uranium impurities by virtue of the assembly process and naturally occurring impurities of uranium within the zirconium. Also, the materials used in the construction of the reactor coolant loop will not be free of corrosion. The type of plant will determine to a large extent the relative migration of these materials to other regions or systems. 1.2 FISSION PRODUCT ACTIVITY When cladding material is contaminated with uranium impurities or when defects in the cladding occur, there will be fission products released to the reactor coolant. The amounts of these fission products will depend on the degree of fuel exposure and the degree of mobility of the fission product and its half-life. The noble gases, their decay daughters, and the radioiodines tend to appear most prominently in reactor coolant. The noble gases are isotopes of the inert gases Krypton and Xenon. They are chemically non-reactive because their outer-most shell of electrons is full. As elemental gases, they are extremely small and can diffuse through the smallest of defects. Tritium is a low-yield fission product but has a long half-life of 12.3 years. Tritium also easily diffuses through zircaloy fuel cladding. Since tritium easily combines with oxygen in the reactor coolant to form tritiated water, and since this tritium follows the same chemistry as hydrogen, tritium is not removed by the various purification systems in the plant and will accumulate as the plant operates. Nuclear plants may operate with fission product activity released by 1% defective fuel. The term defective fuel is normally taken to mean that the fuel is exposed to coolant via defective cladding. Therefore, 1% of the fission products in the fuel could possibly migrate through the defect to the reactor coolant. Trace amounts of uranium in the zircaloy fuel cladding (tramp uranium) will fission in the same way as the uranium in the fuel pellet. Fission fragments travel very short distances, usually only 7-11 microns (diameter of human hair is approximately 10 microns) in zirconium making it unlikely for fission fragments from fuel pellets to reach the coolant. Fission product activity in the coolant from tramp uranium is small.


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A typical fission product activity plot versus core life is many orders of magnitude higher when defective fuel is present. It is this resultant increase in fission product activity that makes monitoring fission product activity a reliable monitor for fuel element cladding integrity. Typical fission products found in reactor coolant are listed below. These nuclides are grouped as halogens, noble gases, and soluble metal ions.

Common Fission Products and Half-Lives1

HALOGENS Iodine – 131 8.04 days Iodine – 132 2.3 hours Iodine – 133 20.8 hours Iodine – 134 52.6 minutes Iodine – 135 6.61 hours

NOBLE GASES Xenon - 131m 11.84 days Xenon - 133m 2.19 days Xenon –133 5.25 days Xenon -135m 15.36 minutes Xenon -135 9.11 hours Xenon –138 14.13 minutes

Krypton - 83m 1.83 hours Krypton - 85m 4.38 hours Krypton – 87 76.3 minutes Krypton – 88 2.84 hours

SOLUBLE METAL IONS Cesium – 134 2.06 years Cesium – 137 30.17 years Cesium – 138 32.2 minutes Barium - 140 12.79 days

Lanthanum – 140 40.22 hours Strontium – 90 28.6 years

1Radioactive Decay Data Tables, David C. Kocher, 1981

TERTIARY FISSION PRODUCT Tritium 12.3 years

The halogens (specifically the radioiodines) are of concern because of the thyroid dose due to iodine inhalation or ingestion following a reactor plant accident. To our benefit, these radioiodines are easily detected, are non-volatile, are easily cleaned up by purification ion exchange, and have relatively short half- lives (8 days or less).


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The noble gases (xenon and krypton) are only of concern if there is a path for their release to the environment. Noble gases are not removed by ion exchange in the purification system, so they build up to saturation levels in the reactor coolant, meaning that the rate of production and decay are equal. In Boiling Water Reactors (BWR), these noble gases are entrained in the steam and, after passing through the turbine, are continually vented to the environment through the Condenser Air Ejector. For this reason, the limits on release of noble gases by BWRs form the bases of operations with fuel rod defects. These concentrations of noble gases can cause high radiation levels in the turbine buildings of BWRs. In Pressurized Water Reactors (PWR), noble gases are vented (also called degasification) from the Volume Control Tank of the Chemical and Volume Control System and collect in the Gaseous Radwaste System. After allowing for decay of these radioactive gases, the contents of hold-up tanks are released to the environment. When steam generator tube leakage is experienced, the fission product noble gases can leak through the steam generator tube flaws to the secondary side where it travels through the same path as in the BWR plant. Soluble metal ions are not effectively removed by filtration; therefore, the ion exchange process is used to remove nuclides like Cesium. ACTIVATED METAL PRODUCTS Some corrosion and wear products can be activated by the absorption of a neutron as they pass through an operating reactor core. These radioactive particles can deposit in low flow areas of plant systems, causing the buildup of radiation levels in these areas. Using corrosion-resistant materials, proper control of chemistry and removal of corrosion products can minimize these radiation levels. Surface areas made of stellite, which contains Cobalt-59, represent a small fraction of the total system surface area. However, stellite is a significant contributor to the radiation buildup since Cobalt-59 becomes irradiated to Cobalt-60. Extensive efforts have been made to reduce or remove the use of stellite in reactor plant systems to minimize the Cobalt-60 source term and thereby reducing background radiation levels during maintenance periods. Natural cobalt (100% Co-59) has a high absorption cross-section for neutrons, and, in addition, its activation product, Co-60, has a long half- life (5.27 years) and high-energy gamma emissions (1.33 and 1.17 Mev) when it decays. The equation representing the activation of cobalt is:

( ) 6059 , − →− CoCo γη

A major activated corrosion product is Co-58. This is formed by the activation of Nickel (Ni-58), a major component of stainless steels and inconel found in steam generators. This seems to be a major


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source of activity especially in plants that have installed new steam generators. The equation representing this activation is:

( ) 5858 , − →− CoNi ρη

Co-58 has a 70-day half- life and emits a 0.81 MeV gamma ray upon decay. Other activated corrosion products that are found in the reactor coolant are Fe-59, Mn-54, Cr-51, Sb-124, Sb-125, and Zr–95. 1.4 ACTIVATED WATER AND IMPURITIES The non-fission gaseous activity in the reactor coolant is due to either activation of oxygen or the activation of Argon - 40, a natural constituent of air. The five major activation products of oxygen and their half- lives are as follows: ISOTOPE SOURCE HALF-LIFE

N13 13,16 NO → αρ 9.96 minutes

N16 16,16 NO → ρη

7.14 seconds

N17 17,17 NO → ρη 4.17 seconds

O19 19,18 OO → γη 26.9 seconds

F18 18,18 FO → ηρ 110.0 minutes

Any gaseous activity in a BWR will go with the steam and eventually pass out of the system via the air ejector. The N-16 isotope, in particular, emits gamma rays with energies of 6.13 and 7.11 MeV upon decay and is the major source of activity through the main coolant system of both BWRs and PWRs. In a BWR, N-16 is the main source of activity in the steam lines during power operation. These high-energy emissions are the reason why access to areas around the steam components is restricted during power operation. BWRs operating under Hydrogen Water Chemistry (HWC) conditions tend to have higher Main Steam Line dose rates due to the production of ammonia in the Reactor and its carryover in the steam. This ammonia carryover consists of extra N-16 and N-13 which may significantly increase (5 to 8 times) the dose rates over non-HWC environments. When the reactor is shutdown, the N-16 activity level drops off very quickly because of its very short 7.1-second half- life. An ALARA tool to reduce exposure from N-16 gamma is system design. Specifically, sufficient delay time is provided in the design of sampling lines to ensure that the isotope decays to negligible levels before the coolant reaches the sample point.


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Noble Metals (Platinum and Rhodium) are added to the reactor vessel internals to increase hydrogen efficiency by lowering the oxygen concentration. These elements act as catalysts to enhance the recombination of hydrogen with oxygen. Less hydrogen is required to achieve greater protection from intergranular Stress Corrosion Cracking (IGSCC). Less hydrogen means lower at-power dose rates from Nitrogen-16. Fluorine-18, a contributor to the liquid activity of PWRs, is very soluble in water and is produced from the interaction of a proton with the Oxygen-18 isotope found in water. In a BWR, it is a contributor to feedwater activity. Additional gaseous activity in the reactor coolant is due to Argon-41 (Ar-41), which occurs from the activation of Ar-40, argon being a natural constituent of air. When deaerated makeup water is used, the gaseous activity is usually quite low and presents no operational problems. If a high Ar-41 activity level does occur, it is usually due to an introduction of air into the reactor coolant system via makeup water. 2.0 PROTECTION AGAINST CONTAMINATION Radioactive contamination is defined as the occurrence of radioactive material in areas where it is not desired. In a nuclear power station, there are large amounts of radioactive material available. This is not a problem as long as the material is where it is supposed to be. If a pump or valve should leak radioactive water onto the floor and a worker walked through the spill and tracked it throughout the station, a very serious situation could develop. The potential for contamination is large, but if proper procedures are followed in the holding of radioactive material, contamination control is not a significant problem. This lesson will describe how radioactive contamination is controlled in the station and how you can protect yourself from contamination. When engineers designed the nuclear power station, contamination control was already being considered. The ventilation system for example, was designed to minimize the spread of radioactive contamination. Administration of the station includes the use of specific procedures for the control of contamination. The most important ingredient in contamination control, however, rests with the individual worker. If you ignore proper contamination control procedures, all other protection will be ineffective. 2.1 PLANT DESIGN FEATURES There are numerous piping systems composed of many different pumps, valves and gauges in a nuclear power station. It would be impossible to design all these components to completely contain all radioactive material in the systems. Engineering controls can, however, limit the spread of contamination and make its control easier. The contaminated liquid control and station


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ventilation systems are two systems that have been designed by engineers to aid in the control of contamination. Floor drains from contaminated areas and equipment drains such as reactor coolant pump-seal-leak-off are part of the contaminated liquid control system. Many pump shaft seals are lubricated and cooled by a low flow of water. In some cases this water is contaminated with radioactive material. If this water were allowed to flow to the floor, contamination control would become a real problem. Instead, this seal water is collected in catch basins and directed to the liquid radwaste system. The water is then processed and either disposed of as waste or reused in the station. If an area were to become contaminated and cleaning water were allowed to flush down the drains to a normal sewage system, contamination could be spread to the environment. To avoid this, any floor drain that has a high potential for draining contaminated areas is directed to the liquid radwaste processing system. These are examples of engineered contamination control methods but there are some that are even simpler. As an example, simply directing the flow to one of the floor drains described above can control contamination. If the floor is pitched in the direction of the drains, contamination control is easier. Curbing, a raised concrete edging, is another method that is used to control contamination. Concrete is porous material. If it were soaked with radioactive water, the water would penetrate resulting in a fixed contamination problem with walls or floors. To eliminate or minimize this, the engineers will specify that potentially contaminated areas be painted. Generally, an epoxy-based paint is used to form an impervious barrier. The paint will also make decontamination of the area easier should it become contaminated. 2.2 PLANT PROCEDURES Design features and engineering planning can contribute to effective contamination control but more controls are necessary. Another method of controlling the spread of contamination is through administrative procedures. There are many procedures used to run a nuclear power facility, procedures for operations, refueling, power ascension, and radiation protection. Some of the plant procedures used for contamination control would typically include the following: * Radiological posting and boundary control procedures * Radiological monitoring procedures * Contaminated equipment control procedures * Radiation work permit procedures * ALARA procedures * Area decontamination procedures


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There are many boundaries in a nuclear power station that aid in the control of radioactive contamination. Working from the inside out, the first barrier is the cladding of the nuclear fuel itself. It serves to contain the fuel and the radioactive fission products that would result in massive contamination of the primary water if released. The second barrier is the reactor pressure boundary. This boundary contains the primary water of either a boiling or pressurized water reactor. If some of the fission products were to leak past the fuel cladding, this second barrier would minimize the spread of contamination. Posting of contaminated or potentially contaminated areas with warning signs, barrier marking tapes or ropes and step-off pads serves as a third barrier to the spread of contamination. If we require that all personnel exiting a contaminated area be frisked or survey themselves for radioactive contamination, we have yet another barrier to the spread of contamination. But all of these are still not enough. Radiation Protection personnel will usually establish passive survey monitors at exits to major buildings of the facility and at exits from the "Protected Security Area" of the station. This means that protection is provided in depth. In fact when you leave a radiologically controlled area, you may be checked for contamination several times. Routine surveys for radiation levels, contamination levels, and airborne radioactivity levels are performed to give the current status of plant radiological conditions. This survey information is used by radiation protection personnel to designate what protective clothing, respiratory protection or radiation monitoring devices are required to complete a specific task. You find out what is required when you read your radiation work permit prior to entering one of the controlled areas.

2.3 USE OF POSTING OR STATUS BOARDS Radiation protection department personnel are required to survey various areas of a nuclear power station on a routine and special basis to determine radiation and radioactive contamination levels. Then they usually complete some type of survey map showing points surveyed and levels detected. To assure that all personnel are aware of the levels in the various areas of the station, results of the surveys are posted in conveniently located areas so that all personnel may review this information prior to starting work in these areas. It is the responsibility of all personnel to be aware of the radiological hazards in the areas where they work. They should check radiation/contamination levels prior to entering the work area. If there are any questions or confusion about the information on the survey maps, radiation protection personnel should be contacted before entering the area. The Radiation Work Permit (RWP) will list the radiation/contamination levels in the specific work area to which you are assigned. This does not preclude the use of the status boards. The status boards will give an overall awareness of the radiological status of the station.


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If tools are used in a contaminated area, they are considered contaminated until proven otherwise. Procedures may include bagging in color-coded bags, but regardless of the encapsulation method used, tagging and identifying these tools prior to removing them from a contaminated area all serve to minimize the spread of contamination. Double bagging is a method used to ensure that removing contaminated tools from an area will not result in the spread of contamination. Area decontamination is another method of contamination control. When decontaminating an area, care should be taken since the indiscriminate use of mops, hoses, or brooms could result in the spread of contamination. The decontamination process by definition consolidates radioactive material during the cleanup process. Close monitoring of area dose rates should be part of decontamination planning. 2.4 COMMON SENSE RULES TO PROTECT AGAINST CONTAMINATION The five common sense rules given in this section will protect you and others from becoming contaminated. Remember them and follow them at all times. As a Radiation Protection Technician, it is your responsibility to enforce/reinforce these rules starting by modeling the appropriate behaviors.

∗ The first common sense rule is no smoking, drinking, or eating in a contaminated area. If a cigarette becomes contaminated, radioactive material will be inhaled, even if you do not smoke it in a contaminated area. The same is true for food or drinks. These items can become contaminated very easily by radioactive particles settling on them or by contamination transfer when you pick them up. Eating, drinking, or smoking contaminated items will allow contamination to enter your body. The best precaution is not to take food, drinks or cigarettes into a contaminated area.

∗ The second rule is wearing your protective clothing properly. Protective clothing must be

worn properly, or it will not protect you. The key to wearing protective clothing properly is to don and doff correctly. Steps in dressing that provide maximum protection and steps in undressing that minimize the spread of contamination will be covered later.

∗ The third rule is wearing your respirator properly. Different types of respirators will be

discussed later, but this rule applies to all of them. Even the best respirator will not protect you if not worn correctly.

∗ The fourth rule is to always monitor. Monitors may be provided at the step-off pad in the

work area, at the access control point, and at the plant gate. Monitoring assures that you


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are not carrying contamination away with you. Techniques of monitoring will be discussed later. Always take the time to monitor yourself correctly.

∗ The fifth rule is awareness, and apply the other four rules and all procedures. The design

controls, plant procedures, and common sense rules are all intended to do one thing, protect you. You are protected by all the controls, and you are the one who makes the system work. You are also the one who can ignore rules and precautions and thus keep the system from working. If this happens, you would not only inconvenience yourself by having to undergo decontamination, but you could inconvenience other people by tracking contamination into their work areas or into clean areas.

3.0 RESPIRATORY PROTECTION Respiratory Protection Programs at Nuclear Power facilities are governed by two regulatory authorities; the Nuclear Regulatory Commission (NRC) and the Occupational Safety and Health Administration (OSHA). The NRC and OSHA have signed a Memorandum of Understanding that outlines the jurisdiction of each agency. The NRC has regulatory jurisdiction whenever the atmospheric hazard or contaminant is composed wholly or in part with licensed or byproduct radioactive material. OSHA has jurisdiction for non-radiological atmospheric hazards and contaminants. Some utilities combine the two programs under one Respirator Program Administrator (RPA); others maintain the programs split and will have a radiological RPA and an industrial RPA. Only specially trained personnel can prescribe respiratory protection devices. A Respiratory Protection Program enables personnel in the various areas of the plant, to work safely, no matter what hazards may be in the atmosphere. The hazards associated with working in the plant may range from working in oxygen deficient spaces such as an unventilated tank, a steam generator, or a space with an atmosphere containing chemical contaminants, to working in an atmosphere with airborne particulate or gaseous radioactivity. When an area is deficient in oxygen, below approximately 19.5% or contains high levels of toxic or nuisance contaminants, this area may be referred to as Immediately Dangerous to Life and Health (IDLH). This means that "conditions that pose an immediate threat to life or health, or conditions that pose an immediate threat of severe exposure to contaminants which are likely to have adverse effects on health" exist as stated in 29 CFR 1910.134 (b). Process or engineering controls are required by regulation. When process or engineering controls are not practical, the licensee must increase monitoring and limit intakes by access controls, limiting exposure times, using respirators, or using other means to keep Total Effective Dose Equivalent (TEDE) ALARA.


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For the remainder of this discussion, we will limit ourselves to the control of airborne radioactivity. Common sense rules can aid in the control of radioactive contamination but what can be done to protect ourselves in the event that the contamination is in the air we breathe? If we enter a contaminated area, we can protect our skin from becoming contaminated by wearing protective clothing. How do we avoid inhaling contaminated air? If a radioisotope were breathed into our lungs it could become an internal hazard. Unlike the loose surface contamination we have discussed so far, we could not avoid the internal contamination. This means that respiratory protection is essential 3.1 PROTECTION FACTORS Respirators provide protection from inhaling radioactive material, but how much protection do they actually afford the wearer? A term that is used to designate the amount of protection afforded is the protection factor (PF). The Derived Air Concentration (DAC) of the isotopes involved is used to calculate PF, but PF has nothing to do with DAC. We are concerned with relative protection only, not the actual concentration. For example:

∗ If the airborne concentration in a work area is 1.5x10-6 µci/cc, and the isotope in the air sample is Cesium-137 having a DAC value of 6.0x10-8 µci/cc, what respiratory protection device should be worn?

∗ The Radiological Protection staff knows that Cesium-137 is a particulate isotope, so an

air-purifying respirator will be sufficient. To calculate the required protection factor they will divide the actual airborne concentration by the DAC for that specific isotope.

DACion Concentrat Airborne

= PF This calculation shows that a respirator that will supply a protection factor of at least 25 is required to enter the area because the airborne concentration in the work area is 25 times the DAC for Cesium-137. Generally speaking, a respirator is selected that exceeds the protection factor required. The federal government tests all respiratory protection devices before they are placed on the market. Then the government assigns appropriate protection factors (PFs). In the case of air-purifying respirators, an assigned protection factor of 1000 is the maximum allowed.


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There are two other types of respiratory hazards to be considered. An absorption hazard results when the radioisotope in question can be absorbed through the skin. An example is tritium. Approximately one third of tritium intake occurs by absorption through the skin. It becomes an internal hazard once absorbed and its removal is based on biological and radiological half- life. The inert gases such as xenon, krypton, and argon pose the second type of hazard, a submersion hazard. The inert gases are also called the noble gases. They are inert, meaning that they do not readily interact with other elements. If these gases are unlikely to interact, it can be seen they would not be absorbed through the skin. In fact, they would not be absorbed through the cellular membranes of the lungs either. Noble gases or inert gases, therefore, are a submersion hazard. The maximum permissible concentrations of the noble gases are based on external radiation exposure limits. 3.2 AIR-PURIFYING RESPIRATORS There are two types of respiratory protection devices, atmosphere -supplying and air-purifying respirators. There are many different styles of the two basic types. We will discuss the styles most commonly used in a nuclear station. Air-purifying respirators purify the air that passes through them before you breathe it. This purification is generally accomplished by filters and is a mechanical process. The contaminant is captured in a fibrous medium, usually fiberglass, sometimes cellulose, and mechanically filtered out of the breathing air. When you inhale while wearing a negative pressure air-purifying respirator, you create a negative pressure inside the mask. This negative pressure causes an inhalation valve to open, air flows into the particulate filter, is cleaned of the contaminant, and flows into the facepiece of the respirator. When you exhale, a check valve closes so that exhaled air will not reverse, an exhalation valve simultaneously opens and the exhaled air is returned back to the atmosphere. This is called an open cycle, which has negative pressure inside the mask when you first inhale. That negative pressure could also pull in contaminated air from any leaks around the face seal of the mask. Because of this possibility, negative pressure air-purifying full face respirators or any full face respirator operating in the negative pressure mode is limited to a PF of 100. While wearing a positive pressure air-purifying respirator, a blower forces ambient air through a filter, supplying the mask constantly with positive pressure air. This prevents inward leakage of the contaminated atmosphere around the facepiece seal. This type of respirator is referred to as a Powered Air Purifying Respirator (PAPR). The PAPR has a PF of 1000 while the blower is running. In the case of both the positive and negative pressure air-purifying respirators, particles are filtered mechanically through the filter media. The air-purifying respirator has specifically designed filters called "sorbents" which through a process called "adsorption," allow the sorbent


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to adsorb iodine, based on the following factors: ambient iodine concentration, water content of the ambient air, temperature, and individuals breathing rate. Since noble gases such as Xenon and Krypton do not chemically react, they will not be adsorbed in the sorbent. Table 1 lists the various protection factors assigned to the different types of respirators. Table 1 - Protection Factors for Respirators 10 CFR 20 Appendix A, Assigned Protection Factors for Respirators Protection Factors Description Modes (a) Particulates

Only Particulates, Gases & Vapor

I. Air-purifying Respirators (Particulates only) Facepiece, half NP 10 Facepiece, full NP 100

Facepiece, half (PAPR) PP 50 Facepiece, full (PAPR) PP 1000

Helmet/hood (PAPR) PP 1000 II. Atmosphere-Supplying Respirators (Particulate, Gases, & Vapor) 1. Air - line respirator Facepiece, half D 10

Facepiece, half CF 50 Facepiece, half PD 50

Facepiece, full D 100 Facepiece, full CF 1000 Facepiece, full PD 1000 Helmet/Hood CF 1000

Suit CF 1 2. Self-Contained Breathing (SCBA)

Facepiece, full D 100 Facepiece, full PD 10,000 Facepiece, full, recirculating D 100 Facepiece, full, recirculating PD 10,000

III. Combination Respirators


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Any combination of air-purifying & atmosphere-supplying respirators.

Assigned protection factor for type and mode as listed above.

Mode symbols are defined as: NP = Negative Pressure PP = Positive Pressure D = Demand (negative pressure inside respirator) PD = Pressure Demand (always positive pressure inside respirator) CF = Continuous Flow (positive pressure inside respirator) Protection Factor is the degree of protection a respirator provides its user. It is defined as the ratio of ambient airborne concentration divided by the inha led airborne concentration. Exposure to filterable contaminants may be calculated using the following formula:

Concentration Inhaled = Factor Protection ionConcentrat AirborneAmbient

∗ Only respirator users that have successfully completed medical screening, training, and

fit testing may take credit for the protection factors a respirator provided. ∗ Protection factors apply for air-purifying respirators only if they use 99.97% efficient

filters. ∗ Protection factor does not account for exposure due to skin absorption from special cases

such as tritium oxide. For tritium oxide, one third of the exposure is by absorption through the skin. Therefore, the overall protection factor is 3 when atmosphere-supplying respirators are used.

National Institute for Occupational Safety and Health (NIOSH) approval is currently unavailable for atmosphere-supplying suits. NRC recognizes the suits may be used in an acceptable respiratory protection program as long as other minimum requirements (except fit-testing) are met. No credit for protection in these one and two-piece suits can be taken unless written approval from the NRC is granted (Reg. Guide 8.15, 4.12.2). Therefore PF = 1. These devices may be used as emergency devices in unknown concentrations for protection against inhalation hazards.


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A facepiece is a tight- fitting enclosure over all or a portion of the face. The full-facepiece mask is commonly used. The full- facepiece mask (Figure RP-2-1) completely encloses the eyes, nose, mouth and chin. It is supported by a head harness attached to the facepiece at five or six points or has an adjustable, semi-rigid, "welder's type" suspension attached at two points at the temples. Facepieces are generally constructed of silicon rubber or flexible plastic. Full- facepieces have one or two transparent lenses for viewing.

Experiments have shown that a PF of 100 can be assigned to a full- facepiece, negative pressure filter respiratory system. Because experimental data on sorbents is not well established, no credit (a PF of 1) may be taken for the use of sorbent canisters or cartridges for protection against radioactive gases or vapors. A typical sorbent material is activated charcoal. Activated charcoal is manufactured by first making charcoal from coconut shell, bituminous coal, or petroleum sludge. The charcoal is oven baked with a steam over-blanket to keep out oxygen. This baking forms many cracks and crevices within the charcoal and vastly increases its surface area for adsorption. The surface area of activated charcoal can range from 700 - 1800 square meters per gram of charcoal. One limitation of all air-purifying respirators is that they only remove a specified contaminant from inhaled air. They DO NOT supply oxygen. Because they do not supply oxygen, they cannot be used in atmospheres that are deficient in oxygen. Also, since particulate filters are highly efficient they will clog quickly if they are used in smoky atmospheres. They should not be used to fight fires for these reasons. To fit a facepiece properly, begin by placing your chin in the chin-cup and then pull the straps over your head. The head harness should be smoothed down over your head, which can be done by gently stroking the harness from front to back. Make sure that the facepiece is positioned correctly. Tighten the straps first at the chin, then the temple, and, finally, the head. The straps should not be tight enough to disfigure the face or cause a bulging. They need be only tight enough to hold the mask in position and keep it from slipping. If a mask is too tight, it may leak. This sequence assures you of a proper fit around the mouth and nose first.

RP- 2-1 Full Facepiece


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RP-2-3 Supplied Air Hood

A negative and positive pressure user seal test should be performed any time you don a respirator. To perform a NP seal test, place your hand, palm up, over the inlet to the filter. Inhale and as the facepiece collapses towards you, hold this condition for ten seconds and observe for leakage; if it moves away from you, there is a leak. If leakage occurs, adjust the straps and try again. If it continues to leak, replace the respirator and test again. To perform the positive pressure seal test, place the palm of your hand over the exhalation valve and exhale gent ly. The facepiece should bulge outward until a leak develops between your face and facepiece; leakage is not allowed back through the filter. 3.3 ATMOSPHERE SUPPLYING RESPIRATORS An atmosphere-supplying respirator furnishes breathable air from an uncontaminated supply, such as a compressed breathing air cylinder or a breathing air compressor (an air-line supplied respirator). There are two types of atmosphere-supplying respirators: airline respirators and self-contained breathing apparatuses (Figure RP-2-2).

3.3.1 AIR LINE RESPIRATORS

There are many different types of air supplied respiratory protection devices. Included in these are: full facepiece masks, hoods, helmets and full air suits. Figure RP-2-3 shows an atmosphere-supplying hood. The hood is a loose fitting enclosure over the head, neck, and shoulders, gathered around the neck or below the shoulders to ensure a snug fit. It is generally constructed of light, non-rigid plastic, or coated or impregnated fabric, and has a large transparent viewing window. The drape part of the hood may be of single or double thickness to allow for taping to keep out loose surface contamination. The helmet is similar to the hood, but of more rigid construction. It provides some impact protection for the eyes, face, and other parts

of the head. (Some helmets are approved as hard hats.) Air is introduced into the head enclosure of a hood or helmet. It flows past the breathing zone and escapes around the gathering perimeter,

RP- 2-2 Full Facepiece Mask


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so there is no need for an exhalation valve. Both of these devices generally contain some noise reduction device to lower the noise of the flow of inlet air.

The supplied-air suit (Figure RP-2-4) is made of plastic or coated or impregnated fabric. It is maintained under positive pressure by an airline supply. Air is distributed within the suit by a system of ducts for the head, trunk and extremities. Air exits through the suit closures of through special exhaust valves. To avoid heat exhaustion, air must be supplied for cooling as well as for breathing. Cooling equipment, such as a vortex tube or a refrigerated air supply, may also be required at high ambient temperatures. There are three primary modes of operation for airline respirators. They are continuous flow (CF), demand (D), and pressure demand (PD).

RP-2-4 Two-Piece Supplied-Air Suit

As the name indicates, the continuous flow respirator provides a continuous flow of breathable air or oxygen. This type of respirator may be used with a full- facepiece mask, a hood, a helmet or a suit. The demand respirator is usually situated between the breathing tubes leading to the facepiece and a small diameter pressure line. (The pressure line comes from a high pressure air source, such as a compressor or breathing air cylinder.) Sometimes the demand regulator is mounted directly on the facepiece. The regulator has a diaphragm-actuated valve that opens on inhalation and allows air to flow into the facepiece as long as there is a negative pressure. Because the negative pressure can cause leakage of contaminants into the facepiece where it seals to the face, the demand respirator does not protect any better against contaminants than an air-purifying respirator with the same facepiece. The demand regulator valve shuts off the air supply during exhalation. The pressure in the facepiece is then the same as the pressure in an air-purifying respirator during exhalation.


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In the pressure demand respirator, a spring-loaded regulator and exhalation valve combination provides a flow of air into the facepiece that maintains a slight positive pressure at all times. Any outward leakage around the facepiece seal results in greater air consumption than with the demand respirator. If the facepiece fits properly, there is no outward leakage, and, therefore, no increase in air consumption. The pressure demand respirator requires a special exha lation valve that is available only with full- facepiece masks. A facepiece that is fitted with a demand-type exhalation valve cannot be used with a pressure demand regulator since it would result in a continuous flow of air to the atmosphere and the usable lifetime of the respirator would be shortened drastically. Most airline respirators provide protection against high levels of contamination, but no device is 100% efficient. Some leakage into the facepiece may occur, particularly with demand respirators. Many of the airline respirators and air-purifying respirators use the same facepiece. Beards and eyeglasses may not be worn with these respirators since the hair or eyeglass temple bars will interfere with the sealing surface of the mask and allow leakage. There are limitations in the use of airline-supplied respirators. The length of the airline is the most obvious. As the length of hose increases, the pressure drop across the hose increases proportionately. This means that the inlet pressure would have to be increased, so pressure becomes a problem. The length of the hose can also be a concern, since it restricts the movements of the worker. The hose is a problem because it is fragile. If it is rubbed over a sharp object, it could be cut. Since no auxiliary air supply is carried normally with airline-supplied respirators, they cannot be used in areas that are immediately dangerous to life and health (IDLH). 3.3.2 SELF-CONTAINED BREATHING APPARATUS There are two types of self-contained breathing apparatus (SCBA). The first and most commonly used is the open-circuit device and the second type is the closed-circuit device. In the open circuit model, the air flow comes from a tank carried on the back through a regulator, that is chest, belt, or facepiece mounted, to the facepiece where it is inhaled and then exhaled through an exhalation valve. This type of respirator has compressed air as its source. The second type, closed circuit device, actually re-circulates inhaled air. The air passes through a sorbent material that removes carbon dioxide, flows to a mixing chamber where additional oxygen is added and returns to the facepiece for re-breathing. There are both demand and pressure-demand type regulators available for both of the above types of SCBA. These regulators have the same limitations as demand and pressure-demand


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airline supplied respirators. One advantage to this type of respirator is that it will supply oxygen, so they could be used in oxygen deficient atmospheres. A disadvantage of self-contained breathing apparatus is their weight. A thirty-minute air supply is compressed with 2200 lbs. (some manufacturer’s designs go as high as 4500 psig, e.g., MSA) force into a steel or aluminum tank. To hold this pressure, a sturdy tank is required, and this means weight. Some manufacturers have recently introduced 30 minute and 1 hour air supply tanks that are wrapped with fiberglass or carbon fiber to allow lighter construction. Air supply tanks are given ratings of 30 minutes, 1 hour, etc. Rarely will anyone get the rated time from a SCBA bottle because of the environmental and physical variables that can affect the user’s breathing rate. For example, when performing strenuous work, you may use up a 30 minute rated air supply in 20 minutes or less. All SCBAs are required to have warning devices when the air supply is becoming exhausted. Generally, when this alarm is sounded, an escape supply of approximately 5 minutes of air remains. Another limitation to SCBAs is their physical size. If you have to climb a ladder with a large thirty-pound tank on your back, there could be real access problems. Work in confined spaces would be difficult. All of these respiratory protective devices work, but a large measure of how well they do the job is up to you, the individual worker. You should look at a respirator the same way you would a life jacket. It can do the job, but if you don't wear it properly, it won't save you or protect you. The proper respirator must be used, it must be fitted properly, and its limitations must be realized. Even when all of these steps are followed, there is the possibility that something might go wrong. You should know this, and be prepared to leave the area immediately in case of equipment malfunction, physical or psychological distress, procedural or communications failure, significant deterioration of working conditions, or any other condition that might require you to seek relief from respirator use. 3.4 ESTABLISHING A RESPIRATOR PROGRAM Some circumstances where the use of respirators may be justified include:

• Emergencies or unplanned events where immediate personnel or facility protection is necessary.

• Non-routine activities in which engineering controls are not feasible. (Respirators are not used as a substitute for engineering controls.)


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• Unidentified airborne radioactivity concentrations exceeding 1x10-9 µCi/cc beta, gamma or unidentified airborne radioactivity concentration exceeding 0.3 DAC.

• Αirborne radioactivity concentrations has not or cannot be determined. • An unevaluated airborne activity alarm is received from a fixed or portable airborne

radioactivity monitor. All personnel will be required to meet certain criteria for use of respirators. These could include: a medical approval form, documented training, documented fit testing, and documented bioassay screening (a whole-body count). You would NOT be issued a respirator if you failed to satisfactorily obtain a face to facepiece seal with a particular type of respirator, if you were not clean-shaven, or if you were not qualified as stated above. A respiratory protection training program will generally state that all personnel, prior to being allowed to use respirators, must undergo medical evaluation and training. This training is included in general employee training and re-qualification training. The quantitative respiratory fit testing program provides a method for testing personnel to qualify as respirator users. Procedures for respirator selection, issuance, in-field user seal test, and use require specific criteria to be followed. Some main points include:

• Inspection of equipment is an individual responsibility. • Only personnel qualified to repair respirators may do so (NIOSH approval). • Engineering controls shall be used when possible. • SCBAs are not intended for long duration usage. • Do not use air-purifying respirators in oxygen deficient atmospheres. • Avoid prolonged exposure of rubber parts to petroleum vapors. • Eyeglasses must be attached to the mask. • Extended wear (gas permeable) contact lens may be worn with the respirator provided

they were used during the fit test. • Extended wear contact lens may be worn with hood-type respirators provided the user

exhibits no discomfort. • Be careful not to damage the regulator when in a confined space. • Try to minimize movement of mouth, chin and facial muscles. • Use only the protective device specified and don't exceed the stay time. • Do not remove equipment unless there is an emergency.


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Procedures covering respiratory protective device maintenance should outline the maintenance necessary to ensure the equipment is kept in a state of readiness for safe use. OSHA requires that maintenance histories be maintained for emergency respiratory devices. Only qualified personnel trained by authorized manufacturers may repair or adjust reducing and admission valves, regulators, and alarms (used in supplied breathing air systems). Qualified personnel must perform all inspections and repairs, other than the routine pre-use inspection. After use, respirators are cleaned, sanitized, checked for radioactivity and inspected. Generally, all emergency equipment is inspected monthly. A procedure for supply and utilization of quality breathing air will set limits and sampling requirements for the following: oxygen, condensed hydrocarbons, carbon monoxide, carbon dioxide and odor. A respiratory protection equipment acceptance criteria procedure will set purchasing requirements, pre-operational testing, and inspection frequencies for all equipment. All respirators and associated repair parts shall be NIOSH approved. 4.0 PROTECTIVE CLOTHING Protective clothing is used in everyday life for a variety of reasons. We may wear a pair of gloves to protect our hands from sharp thorns or dirt and rocks while working in the garden. A pair of mechanics coveralls will keep grease and oil off work clothes when working on an automobile. Protective clothing in radiation protection is designed to keep radioactive contamination from coming in contact with your skin. Proper use of protective clothing is very important. You will be required to wear protective clothing any time you enter a contaminated area. So it is important that you become expert in its use. 4.1 DONNING PROTECTIVE CLOTHING Procedures for obtaining and donning protective clothing vary from station to station. Generally, you will obtain the proper clothing from storage racks close to the area in which you will be working. You will know what clothing to obtain from your Radiation Work Permit (RWP). You may wear your own modesty garments (surgical scrubs, gym shorts, etc.), shoes and socks, as management can replace these items if they inadvertently become contaminated while you are working. Some utilities will issue modesty garments to be worn under the protective clothing. A typical set of anti-contamination clothing may include a head cover, coveralls, gloves and shoe covers. Actual clothing requirements will be specified on an RWP. Rad Worker training provides information on radiological boundary control, dress and undress policies, entry and egress requirements, and dosimetry placement in or on the coveralls. As a Radiation Control Technician, you are expected to model the proper behavior and enforce management expectations concerning the proper use of protective clothing and station contamination control protocols.


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If coveralls are required by your RWP, you should obtain the proper size from the appropriate storage bin. “Bigger is better” is the best way to judge the proper size. Check all clothing prior to putting it on for cuts or tears in the fabric. Check zippers or Velcro fasteners to insure they fasten properly. Protective coveralls may be made of cloth, paper, rubber, or plastic. Cloth coveralls are most commonly used when a single set of coveralls is required. Multiple sets of coveralls may be required where water contamination could occur (a pair of plastic coveralls would go over cloth coveralls) or where contamination levels are extremely high. Protective clothing is usually donned in a clean area and removed prior to leaving a contaminated area. Gloves keep your hands from becoming contaminated. They are generally made from rubber, but you will notice different thicknesses available for different work. Since the rubber glove is difficult to remove over wet hands, glove liners made of cotton are generally worn. These cotton-glove liners provide little if any contamination protection and should not be considered protective clothing. So, in effect, two layers of gloves are worn. The first is the cotton glove liners and the second, the rubber glove itself. The cuff of the rubber glove should be pulled over the sleeve of the coveralls and taped or restrained in place. If you use tape to secure any protective clothing, ensure you leave a tab on the tape to facilitate removal. This can be especially important in an emergency. Many sites are using launderable barriers in place of tape. The next item of protective clothing to be donned is the cap or hood. Cloth hoods are provided which protect the hair and backs and sides of the neck. If a respirator is needed, you may tape the hood to the respirator, but remember to provide tabs to allow easy removal of the tape. Sometimes two sets of protective coveralls are required by the working conditions. If two sets of coveralls are worn, make sure that your dosimeters are in the pocket of the outer pair. This allows easy access and cuts down the amount of shielding placed over the dosimeters. If you suspect that your dosimeters may become contaminated, tape them in a plastic bag to keep contamination off them. This bag may in turn be taped to the front of the coveralls to allow easy access. If the RWP requires a respirator, it should be donned just prior to entering the work area requiring respiratory protection. Most stations require special training and testing prior to the initial use of respirators. You may be required to attend a basic training course, complete a medical questionnaire, pass a pulmonary function test, and demonstrate proper face seal during a quantitative respirator fit test. Before donning a respirator, check for cracks or tears in the rubber of the face seal. The lens should not be scratched such that vision is impaired and the head straps should be sound. The filter "O" ring seal must be in place and the filter canister(s) installed correctly. 4.2 REMOVING PROTECTIVE CLOTHING


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There are many different procedures for removing protective clothing. Radiation Protection staff establish step-off pad placement. Some stations use a single step-off pad that is considered to be contaminated, others use two step-off pads with the first being contaminated and the second kept clean, and others use a single step-of pad that is considered clean. Follow station procedures or guidelines for removing contaminated clothing. Remember the intention of this clothing when removing protective clothing. Its purpose is to avoid spreading contamination to the clean area and avoid contaminating ourselves. 5.0 PERSONNEL CONTAMINATION ASSESSMENT The As Low As Reasonable Achievable (ALARA) policy stipulates that all personnel are responsible for their radiation exposure. This holds true for contamination control as well. In fact, all stations require personnel to perform monitoring for contamination every time they exit a contaminated area. This could be hand and foot counters, Geiger-Mueller (GM) friskers or count rate meters, or Personnel Contamination Monitors (PCMs). Background count rate in the area where frisking is to take place has to be considered. Generally, a person is considered contaminated if detectable activity is found. A lower background count rate will allow greater detection sensitivity. Once background has been determined, the "frisk" is conducted by slowly passing the probe over the surface of the body. Frisk rate should be 1 to 2 inches per second keeping the probe approximately a half inch from the surface being examined without touching it. If surface contamination is detected, document survey results prior to attempting to decontaminate the individual in accordance with station policies and practices. This survey documents initial contamination levels and indicates if decontamination attempts were successful. 5.1 PERSONNEL DECONTAMINATION A contaminated individual can be apprehensive and embarrassed. ALWAYS, reassure the individual and explain, “what you are going to do” before “you do it.” The best method of personal decontamination is to always start with the easiest method first. If extreme measures are used initially, the surface contamination could be driven further into the pores/surfaces of the skin. Initial decontamination should consist of just water or a soap and lukewarm hand washing of the affected area. An excellent reference document on personal and area decontamination is the "Health Physics and Radiological Health Handbook". After hand washing, further steps in decontamination can be followed as specified in this handbook. Individual station procedures dictate decontamination practices. 5.2 AREA DECONTAMINATION


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Area decontamination is similar to personal decontamination in that the technique used should start with the easiest method. Vacuum (HEPA vacuum) cleaning is one initial method used; plain water is another. Caution should be used not to spread the contamination from a dirty area to a clean area, which would compound the problem. Decontamination is necessary for several reasons. Radiologically, it makes sense to decontaminate to limit the spread of contamination and minimize airborne activity levels. Also, decontamination is necessary to minimize the amount of waste generated since if contamination were spread over a large area, it would create more waste in the subsequent cleanup. Additionally, for health and safety of the public, by decontaminating personnel and areas, we minimize the possibility that they could ingest radioactive material. 6.0 CONTROLLED AREA ACCESS CONTROL Controlled areas are always posted with warning signs. Prior to entering any controlled area, a worker should read all the signs. The worker should bring any questions to the attention of Radiation Protection personnel. Entry to contaminated areas is generally made over a step-off pad. This pad is a contamination control device and may be either "clean" or "dirty" depending on the station's use. 6.1 COMMON SENSE RULES Your role is to oversee radiation workers in the implementation of these rules by coaching, mentoring, or when necessary initiating immediate correction actions.

• Don't eat, smoke, or drink in contaminated areas. • Do not enter an area that is contaminated without Radiation Protection approval. • Always wear protective clothing while working in contaminated areas. • Avoid face contact with any contaminated items • Don’t scratch your nose while you are wearing protective clothing. • Be aware of actions that could cause airborne contamination (even if they are not

your actions). • Notify Radiation Protection if the job scope changes, particularly if systems are to be

opened to atmosphere. • Contain contamination to as small an area as possible by: • Observe contamination posting. • Use proper protective closing removal procedures.


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• Bag all contaminated tools and equipment in radioactive material bags. • Keep all areas as clean as possible by practicing good housekeeping. • Always wear respirators when required by RWP and indicated by posted signs or

Radiation Protection instruction.

7.0 SUMMARY This section identified sources of radiation and radioactive material in an operating nuclear plant. Protective clothing and respiratory protective equipment are examples of equipment used to protect the worker from external or internal radioactive contamination. We are as concerned with radiation exposure as we are with radioactive contamination. Therefore, knowledge of the use of this equipment is pertinent to radiation protection and contamination control. This section also covered features and plant procedure controls that aid in controlling the spread of contamination. In addition, we have discussed the significance of protection factors and explained various types of equipment used for respiratory protection. Proper donning and removal techniques for protective clothing in accordance with plant policies and practices also aids in contamination control.


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PERSONNEL DECONTAMINATION Method Surface Action Technique Advantages Disadvantages Soap and water Skin and hands Emulsifies and

dissolves contaminates.

Wash 2-3 minutes and monitor. Do not wash more than 3-4 times.

Readily available and effective for most radioactive contamination.

Continued washing will defat the skin. Indiscriminate washing of other than affected parts may spread contamination

Soap and water Hair Same as above. Wash several times. If contamination is not lower to acceptable levels shave the head and apply skin decontamination methods

Same as above. Same as above.

Lava soap, soft brush, water

Skin and hands Emulsifies, dissolves, and erodes

Use light pressure with heavy lather. Wash for 2 minutes, 3 times. Rinse and monitor. Use care not to scratch or erode the skin. Apply lanolin or hand cream to prevent chapping.

Same as above. Continued washing will abrade the skin.

Tide or other detergent (plain)

Same as above. Same as above. Make into a paste. Use with additiona l water with a mild scrubbing action. Use care not to erode the skin.

Same as above. Continued washing will abrade the skin.

* Begin with the first listed method and then proceed step by step to the more severe methods, as necessary


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PERSONNEL DECONTAMINATION

Method Surface Action Technique Advantages Disadvantages Mixture of 50% Tide and 50% Cornmeal

Skin and hands Emulsifies, dissolves, and erodes contaminates.

Make into a paste. Use with additional water with mild scrubbing action. Use care to erode the skin.

Slightly more effective than washing with soap

Will defat and abrade the skin and must be used with care.

5% water solution of a mixture of 30% Tide, 65% Calgon, 5% Carbose (carboxymethyl cellulose)

Same as above. Same as above. Use with water. Rub for a minute and rinse.


A preparation of 8% Carbose, 3% Tide, 1% Versene, and 88% water homogenized into a cream.

Same as above. Same as above. Use with additional water. Rub for 1 minute and wipe off. Follow with lanolin or hand cream


*Begin with the first listed method and then proceed step by step to the more severe methods, as necessary


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PERSONNEL DECONTAMINATION

Method Surface Action Technique Advantages Disadvantages Titanium dioxide paste. Prepare paste by mixing precipitated titanium dioxide (a very thick slurry, never permitted to dry) with a small amount of lanolin. If not successful, go on to next step.

Skin, hands, and extremities. Do not use near face or other body openings.

Emulsifies, dissolves, and erodes contaminates

Work the paste into the affected area for 2 minutes. Rinse with soap and warm water. Monitor.

Removes contamination lodged under scaly surface of skin. Good for heavy surface contamination of skin.

If left on too long will remove skin.

Mix equal volumes of a saturated solution of potassium permanganate and 0.2 N sulfuric acid. *Saturate solution of KMnO4 is 6.4 grams per 100ml of H20.) Continue with next step.


Dissolves contaminant absorbed in the epidermis.

Pour over wet hands rubbing the surface and using hand brush for not more than 2 minutes. Rinse with water

Superior for skin contamination. May be used in conjunction with Titanium oxide.

Will remove a layer of skin if in contact with the skin for more than 2 minutes.



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PERSONNEL DECONTAMINATION Method Surface Action Technique Advantages Disadvantages Apply a freshly prepared solution of sodium acid sulfite. (Solution made by dissolving 5 gm of NaHSO3 crystals in 100 ml distilled water.


Removes the permanganate stain.

Apply in the same manner as above. Apply for not more than 2 minutes. The above procedure may be repeated. Apply lanolin or hand cream when completed.

Same as above.

Flushing Eyes, ears, nose, and mouth

Physical removal by flushing

Roll back the eyelids as far as possible, flush with large amounts of water. If isotonic irrigants are available, obtain them without delay. Apply to eye continually and then flush with large amounts of water. (Isotonic irrigant [0.9% NaCl solution]: 9 grams NaCl in beaker, fill to 1000cc with water.) Can be purchased from drug suppliers, etc.

If used immediately will remove contamination. May also be used for ears, nose and throat.

When using for nose and mouth, contaminated individual should be warned not to swallow the rinses


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PERSONNEL DECONTAMINATION Method Surface Action Technique Advantages Disadvantages Flushing Wounds Physical

removal by flushing.

Wash wounds with large amounts of water and spread edges to stimulate bleeding, if not profuse. If profuse, stop bleeding first, clean edges of wound, bandage, and if any contamination remains, it may be removed by normal cleaning methods, as above.

Quick and efficient if wound is not severe.

May spread contamination to other areas of body if not done carefully.

Sweating Skin of hands and feet

Physical removal by sweating.

Place hand or foot in plastic glove or booty. Tape shut. Place near source of heat for 10 – 15 minutes or until hand is sweating profusely. Remove glove and then wash using standard techniques. Or gloves can be worn for several hours using only body heat

Cleansing action is from the inside out. Hand does not dry out.

If glove or booty is not removed shortly after profuse sweating starts and parts washed with soap and water immediately, contamination may seep into the pores.

• Begin with the first listed method and then proceed step by step to the more severe methods, as necessary


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AREA AND MATERIAL DECONTAMINATION

Method Surface Action Technique Advantages Disadvantages Vacuum Cleaning Dry surfaces Removes

contaminated dust by suction.

Use conventional vacuum with efficient filter.

Good on dry, porous surfaces. Avoid water reactions

All dust must be filtered out of exhaust. Machine is contaminated.

Water All nonporous surfaces (metal, painted, plastic, etc.)

Dissolves and erodes

For large surfaces Hose with high-pressure water at an optimum distance of 15 to 20 feet. Spray vertical surfaces at an angle of incidence of 30o to 40o; work from top to bottom to avoid recontamination. Work upwind to avoid spray. Determine cleaning rate experimentally, if possible; otherwise, use a rate of 4 square feet per minute For small surfaces Blot up liquid and hand wipe with water and appropriate commercial detergent

All water equipment may be utilized. Allows operation to be carried out from a distance. Contamination may be reduced to 50%. Water equipment may be used for solutions of other decontaminating agents. Extremely effective if done immediately after spill and on nonporous surfaces.

Drainage must be controlled. Not suitable for porous materials. Oiled surfaces cannot be decontaminated. Not applicable on dry contaminated surfaces ( use vacuum); not applicable on porous surfaces such as wood, concrete, canvas, etc. Spray will be contaminated. Of little value in the decontamination of large areas, longstanding contaminants and porous surfaces.



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AREA AND MATERIAL DECONTAMINATION

Method Surface Action Technique Advantages Disadvantages Steam Nonporous surfaces

(especially painted or oiled surfaces)

Dissolves and erodes.

Work from top to bottom and from upwind. Clean surfaces at a rate of 4 square feet per minute. The cleaning efficiency of steam will be greatly increased by using detergents.

Contamination may be reduced approximately 90% on painted surfaces.

Steam subject to same limitations as water. Spray hazard makes the wearing of waterproof outfits necessary.

Detergents Nonporous surfaces (metal, painted, glass, plastic, etc.

Emulsifies contaminants and increases wetting power of water and cleaning efficiency of steam.

Rub surface 1 minute with a rag moistened with detergent solution then wipe with dry rag; use clean surface of the rag for each application. Use a power rotary brush with pressure feed for more efficient cleaning. Apply solution from a distance with a pressure portioner. Do not allow solution to drip onto other surfaces. Mist application is all that is necessary.

Dissolves industrial film and other materials that hold contamination. Contamination may be reduced by 90%.

May require personal contact with surface. May not be efficient on longstanding contamination.



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AREA AND MATERIAL DECONTAMINATION Method Surface Action Technique Advantages Disadvantages Complexing agents Nonporous surfaces

(especially unweathered surfaces; i.e., no rust or calcareous growth)

Forms soluble complexes with contaminated material.

Complexing agent solution should contain 3% (by weight) of agent. Spray surface with solution. Keep surface moist 30 minutes by spraying with solution periodically. After 30 minutes, flush material off with water. Complexing agents may be used on vertical and overhead surfaces by adding foam (sodium carbonate or aluminum sulfate.)

Holds contamination is solution. Contamination may be reduced by 75% in 4 minutes on unweathered surfaces. Easily stored; carbonates and citrates are nontoxic, non-corrosive.

Requires application for 5 to 30 minutes. Little penetrating power; of small value on weathered surfaces.

Organic solvents Nonporous surfaces (greasy or waxed surfaces, paint or plastic finishes, etc.)

Dissolves organic materials (oil, paint, etc.)

Immerse entire unit in solvent or apply by wiping procedure (see detergents).

Quick dissolving action. Recovery of solvents possible by distillation.

Requires good ventilation and fire precautions. Toxic to personnel. Material bulky.



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AREA AND MATERIAL DECONTAMINATION Method Surface Action Technique Advantages Disadvantages Inorganic acids Metal surfaces

(especially with porous deposits; i.e., rust or calcareous growth); circulatory pipe systems.

Dissolves porous deposits.

Use dip-bath procedure for movable items. Acid should be kept at a concentration of 1 to 2 normal (9 to 18% hydrochloric, 3 to 6% sulfuric acid). Leave on weathered surfaces for 1 hour. Flush surface with water, scrub with a water-detergent solution, and rinse. Leave in pipe circulatory system 2 to 4 hours; flush with plain water, a water- detergent solution, then again with plain water.

Corrosive action on metal and porous deposits. Corrosive action may be moderated by addition of corrosion inhibitors to solution.

Personal hazard. Wear goggles, rubber boots, gloves, and aprons. Good ventilation required because of toxicity and explosive gases. Acid mixtures should not be heated. Possibility of excessive corrosion if used without inhibitors. Sulfuric acid not effective on calcareous deposits

Acid mixtures: Hydrochloric, Sulfuric, Acetic, Citric acids, Acetates, Citrates.

Nonporous surfaces (especially with porous deposits); circulatory pipe systems

Dissolves porous deposits.

Same as for inorganic acids. A typical mixture consists of 0.1 gal. Hydrochloric acid, 0.2 lb sodium acetate and 1 gal. water

Contamination may be reduced by 90% in 1 hour (unweathered surfaces). More easily handled than inorganic acid solutions.

Weathered surfaces may require prolonged treatment. Same safety precautions as required for inorganic acids.



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AREA AND MATERIAL DECONTAMINATION Method Surface Action Technique Advantages Disadvantages Caustics: Lye (sodium Hydroxide) Calcium hydroxide Potassium hydroxide

Painted surfaces (horizontal)

Softens paint (harsh method)

Allow paint-remover solution to remain on the surface until paint is softened to the point where it may be washed off with water. Remove remaining paint with long-handled scrapers. Typical paint remover solution: 10 gal water, 4 lb. Lye, 6 lb. Boiler compound, 0.75 lb. Cornstarch.

Minimum contact with contaminated surfaces. Easily stored.

Personal hazard (will cause burns). Reaction slow; thus, it is not efficient on vertical or overhead surfaces. Should not be used on aluminum or magnesium.

Trisodium phosphate

Painted surfaces (vertical, overhead)

Softens paint (mild method)

Apply hot 10% solution by rubbing and wiping procedure (see detergent)

Contamination may be reduced to tolerance in one or two applications.

Destructive effect on paint. Should not be used on aluminum or magnesium.

Abrasion Non-porous surfaces Removes surface

Use conventional procedures, such as sanding, filing, chipping; keep surface damp to avoid dust hazard.

Contamination may be reduced to as low a level as desired.

Impractical for porous surfaces because of penetration by moisture.



RP-2 of 39

AREA AND MATERIAL DECONTAMINATION Method Surface Action Technique Advantages Disadvantages Sandblasting Non-porous surfaces Removes

surfaces. Keep sand wet to lesson spread of contamination. Collect used abrasive or flush away with water.

Practical for large surface areas.

Contamination spread over area must be removed. Contamination dust is a personnel hazard.

Vacuum blasting Porous and nonporous surfaces

Removes surfaces; traps and controls contaminated waste.

Hold tool flush to surface to prevent escape of contamination.

Contaminated waste ready for disposal. Safety abrasion method.

Contamination of equipment.


RP-2 Radiation and Contamination

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