Regulatory Actions and Follow up Measures against ... · Regulatory Actions and Follow up Measures...

Regulatory Actions and Follow up Measures against Fukushima

Accident in Korea

Seon Ho SONG*

Korea Institute of Nuclear Safety

Int Conference on Effective Nuclear Regulatory Systems, April 9, 2013, Canada

* APR1400 Regulation Project Manager, KINS, [email protected]

Contents

1. Background

2. Strategy for Regulatory Actions

3. Special Safety Inspection (Phase 1)

4. Action Items for Operating Plants (Phase 1)

5. Additional Action Items (Phase 2)

6. Future Works (Phase 3)

Korea Institute of Nuclear Safety-1-

1. Background

� Impact of Fukushima accident on Korea

� As the closest neighbor country to Japan, Fukushima accident gave a big impact on Korea.

� The public were very sensitive to radiation risk from the accident.

� In the early stage of the accident, there was some confusion in decision-making because it was very difficult to get the exact information.

� At that time (March 2011), 21 nuclear power plants and one research reactor were operating and 7 nuclear power plants were under construction in Korea.

-2- Korea Institute of Nuclear Safety

Background

� Radiation Impact on Korea

� Environmental radiation monitoring was enhanced immediately after Fukushima accident.

� Airborne, rain, water, sea water, marine life, etc.

� Radioactive materials were detected in air and rain.


� Impact on Public

� The public were very sensitive to the radiation risks in spite of extremely low level.

� The public strongly required prompt regulatory actions for the safety of domestic nuclear facilities.

2. Strategy for Regulatory Actions

� Korea’s Strategy for Regulatory Actions to Nuclear Facilities

� Regulatory actions against Fukushima accident are phased in including 3 phases.

� First, special safety inspection was immediately performed to all operating nuclear facilities to identify action items based on defense-in-depth approach.

(1st phase)

� Follow-up measures are continuously issued considering detailed evaluations, research results, and/or experiences and lessons learned from international communities. (2nd & 3rd Phases)


Strategy for Regulatory Actions


� Update the Action Items considering Lessons Learned from International Communities. *

� Evaluation of the Effectiveness of the Action Items by using Stress Test and/or PSA *

� Modification of Safety Objective and Goal, and Regulations and Guides considering Beyond DBA.

� Issuance of Action Items by performing Special Safety Inspection

� Preparation of action plan for the implementation *

� Implementation of Action Plans for all Operating Plants *� Feedback of Selected Action Items to Plants under Construction � Issuance of Additional Action Items considering Lessons Learned from International Communities *

1st phase

2nd phase

3rd phase

* required to Licensee also.

3. Special Safety Inspection (Phase 1)

� Special Safety Inspection by Government

� Special safety inspection was performed to 21 operating NPPs and 1 research reactor from Mar. 21 to May 3, 2011.

� Unlikely worst case scenario was considered including

� Extreme natural disaster (earthquake + tsunami)

� Loss of off-site power and failure of emergency DGs (SBO)

� Severe accident

� Objective of special safety inspection

� how well the NPPs are designed against natural disasters;

� how well they can mitigate the severe accident;

� how much effective the emergency response system are in place.


Special Safety Inspection (Phase 1)

� Major Inspection Points of Special Safety Inspection

� Extreme Natural Hazards : Adequacy of the plant design and facilities against natural hazards

� Design against earthquake and seismic capacity

� Design against coastal flooding and inundation protection capability

� Prevention of Severe Accidents : Adequacy of power supply and cooling functions

� Power system and emergency power supply

� Cooling capability in case of SBO and inundation



� Major Inspection Points of Special Safety Inspection

�Mitigation of Severe Accidents : Adequacy of countermeasure capabilities against severe accidents

� Facilities, guidelines, and strategies against severe accidents

� Emergency Response : Adequacy of emergency response

� Emergency response to multi-units accidents

� Facilities, systems, and infrastructure for the protection of local residents and workers



� Results of the Inspection

� Regulatory body issued 50 action items to all operating facilities in Korea based on defense-in depth approach (May 2011) ♣ Attachment 1 (List of 50 Action Items)

� To minimize the impact of extreme natural disaster,

� To make available emergency power and ultimate heat sink, and

� To eliminate the likelihood of severe accident and avoid hydrogen explosion

� Licensee submitted action plans for implementation of 50 action items. (July 2011)

� Regulatory body approved the licensee's action plan. (Oct. 2011)

� All action plans will be completed by the end of 2015.


Defense-in-Depth Approach


To prepare appropriate counter measures for each stage of postulated accident scenario

Strengthen

Emergency

Preparedness

Mitigate

Severe Accident

Prevent

Severe Accidents

Protect NPPs from

Extreme

Natural Hazards

To improve emergency preparedness and accident management considering multi-units accident

To ensure the containment integrity to prevent hydrogen explosion

To secure reactor cooling and power supplycapabilities under the failure of safety system bynatural hazards

To prepare countermeasures against beyond designearthquake and tsunami

4. Action Items for Operating Plants (Phase 1)

� Extreme Natural Hazard (Earthquake)

� Issued 5 action items to secure additional safety upon a premise of earthquake exceeding the design basis

1-1 Installing an automatic seismic trip system

1-2 Improving the seismic capacity of the safe shutdown system

1-3 Investigation and study on the maximum potential earthquake for NPP sites

1-4 Improving the seismic capacity of the main control room (i.e., the earthquake occurrence alarm window)

1-5 Improving the seismic capacity of the entrance bridge of Wolsongnuclear power plant


Action Items for Operating Plants (Phase 1)

� Extreme Natural Hazard (Tsunami)

� Issued 4 action items to secure additional safety on the premise that severe tsunami exceeding the design basis occurs.

2-1 Extension of the height of the sea wall for Kori site

2-2 Installation of waterproof gates and discharge pumps

2-3 Investigation and research study on the design basis sea water level of NPP sites

2-4 Enhancement of sea water intake capability and reinforcement of facilities in preparation of coastal flooding



� Prevention of Severe Accidents

� Issued 11 action items to secure additional safety under assumption of the worst case scenario that a site being inundated due to large tsunami beyond design basis and loss of power supply takes place at the same time

3-1 Securing the availability of a portable electric power generator vehicle and batteries, etc.

3-2 Upgrading design basis of AAC diesel generator

3-3 Fastening the spare transformers with anchor bolts and modifying the fuel injection port of emergency power supply system

3-4 Improving the management for switchyard facilities



� Prevention of Severe Accidents (cont.)

3-5 Ensuring countermeasures against loss of the spent fuel pool cooling function

3-6 Preparing measures of the inundation prevention and restoration of the ultimate heat sink

3-7 Preparing countermeasures for damage of outdoor tanks

3-8 Preparing countermeasures for inundation of the main steam safety valve room and the emergency water pump room

3-9 Improving the fire protection plan and reinforcing cooperation systems

3-10 Improving fire protection facilities and response capability of plant firefighting teams

3-11 Introducing a performance-based fire protection design



� Mitigation of Severe Accidents

� Issued 6 action items to secure additional safety on the premise of the worst case scenario that nuclear fuel melts due to the total loss of cooling function

4-1 Installation of passive hydrogen removal equipment

4-2 Installation of filtered vent system or depressurizing facilities in the containment buildings

4-3 Installation of reactor injection flow paths for emergency cooling water injection from external sources

4-4 Reinforcing education and training for severe accidents

4-5 Revision of the Severe Accident Management Guidelines to enhance the effectiveness

4-6 Development of Low-Power Shutdown Severe Accident Management Guidelines



� Emergency Response

� Issued 11 action items to respond to the worst radiation disasters such as accidents take place at multiple units at the same time

5-1 Securing additional radiation protection equipment for protecting residents near the NPP

5-2 Amending the emergency plan to include such events as the simultaneous emergency at multiple units

5-3 Securing additional protective equipment in preparation for prolonged emergency

5-4 Expanding the equipment of the emergency medical treatment organization

5-5 Reinforcing radiological emergency exercises



� Emergency Response (cont.)

5-6 Devising a means for securing necessary information in the event that there is a prolonged loss of electrical power

5-7 Securing countermeasures for protecting maintenance workers

5-8 Improving the emergency response facilities

5-9 Amending the information disclosure procedure in the event of a radiation emergency

5-10 Evaluating protective measures for residents who live beyond the emergency plan zone

5-11 Reinforcing the performance of emergency alarm facilities



� Long-term operation of NPP

� Issued 8 action items to reinforce the safety of long-term, operating NPPs including Kori unit 1.

6-1 Reinforcing regulatory safety inspections

6-2 Reinforcing the in-service inspection of the main components and pipes

6-3 Establishing and implementing an integrated aging management program

6-4 Reinforcing the management of the performance parameters of the main active components

6-5 Installing a fatigue monitoring system to reinforce quantitative fatigue management

6-6 Reinforcing the integrity of the pressurizer lower head

6-7 Increasing the reliability of shutdown-inducing equipment

6-8 Evaluating the adequacy of human resources

6-9 Increase the reliability of on-site power supply system

6-10 Reinforcing the quality assurance on purchasing components important to safety



� Research Reactor

� Issued 3 action items to research reactor (Hanaro)

7-1 Evaluate the seismic capacity of structures and improve the main control room

7-2 Re-evaluate the site's inundation depth of Hanaro and additional facilities

7-3 Amend the radiation emergency plan, reflecting the complicated radiological emergency condition


5. Additional Action Items (Phase2)

� Application to Operating Plants

� 22 items among 50 action items were completed for operating NPPs by the end of 2012.

� The others would be completed by the end of 2015.

� Feedback to Plants under Construction

� 33 items among 50 action items were feed backed to the plants under construction. (Refer Attachment 1 (*))

� Korea had 7 plants under construction in 2011.

� Regulatory body agreed that some items such as researches on level of earthquake and Tsunami in Korean peninsula were postponed after operating license of 3 plants.


Additional Action Items (Phase2)

� Issuance of Additional Action Items (1)

� Issued by Korean licensee considering lessons learned from international communities

� To apply safety class to the instruments engaged in water level/temperature and radiation level monitoring/measurement of SFP, under severe environment within design base (NRC)

� To secure emergency power for at least one train as long as spent fuels are stored in SFP regardless of whichever operation mode is applied (NRC)

� To secure diesel engine driven and water-tight type flood pumps for removal of flooded water during flooding (WANO)

� To procure long water hoses to bring water from distant water sources for emergency filling (WANO)

� To secure mobile wireless phones, satellite telephones etc. for emergency communication (WANO)


Additional Action Items (Phase2)

� Issuance of Additional Action Items (2)

� Issued through Korean licensee’s self-evaluation

� To develop Extensive Damage Mitigation Guidelines (EDMGs)

� To develop temporary SAMG entrance guideline applicable beyond EOP

� To conduct seismic evaluation for the clean water supply piping system for reinforcement

� To establish a provision to supply emergency power for essential local area coolers (Wolsong unit 1)

� To install auxiliary feed-water reserve tank to increase auxiliary feed-water supply capability (Ulchin units 1&2)


6. Future Works (Phase 3)

� Action Items will be updated considering lessons learned from international communities

� IAEA, OECD/NEA, EU(Stress Test), France, USA, Canada, Germany, Japan, China, and Russia.

� International cooperation is very important to get information and insight against Fukushima accident.

� The effectiveness of the action items will be evaluated by using various methodologies

� Stress test with cliff edge evaluation will be performed for all operating plants in Korea.

� PSA may give us some insight to estimate the effectiveness.


Future Works (Phase 3)

� Review and Modification of Safety Objective and Safety Goal considering Extreme Natural Hazard

� External events could exceed the assumptions used in the design and licensing of a plant, as demonstrated by the events at Fukushima

� Review and Modification of Regulations and Guides considering beyond DBA

� Air crash, Design Extension Condition, etc.

� Periodic update safety requirements for natural hazards


Concluding Remarks(1)

� As of April 2013, the licensee is in the progress of implementation as planned. The regulatory body has set regulatory requirements for each action item and checked the adequacy of actions implemented.

� Since fully understanding the causes and progress of the Fukushima accident requires continuous effort, the regulatory body is developing a national-level process to incorporate the lessons learned from Fukushima into the operation of Korean NPPs.


Concluding Remarks(2)

� The process will cover gathering, analyzing, and evaluating operating experience; preparing action plans at operator and regulator levels; and establishing regulatory requirements to improve the safety of nuclear power plants.

� In accordance with the process, action plans for construction and operation areas will also be in the works.



Thank you

Jeju Island in Korea

Regulatory Actions and Follow up Measures against ... · Regulatory Actions and Follow up Measures...

Documents

Transcript of Regulatory Actions and Follow up Measures against ... · Regulatory Actions and Follow up Measures...