Non-Proprietary Regulatory GAP Analysis Results ...Gap Analysis Results – Regulations Summary...
Transcript of Non-Proprietary Regulatory GAP Analysis Results ...Gap Analysis Results – Regulations Summary...
TM© 2012 NuScale Power, LLC
TM
Regulatory Gap Analysis Results:Regulations Requiring Further Consideration
Derick Botha and Gary Becker
December 3, 2012
TMNonproprietary
© 2012 NuScale Power, LLC2
Agenda• Purpose• Background• Regulatory gap analysis process• Gap analysis results – regulations• Summary• Feedback and next steps
TMNonproprietary
© 2012 NuScale Power, LLC3
Purpose• Review gap analysis approach in assessing regulations• Discuss regulations requiring further consideration
– 17 regulations identified in summary report
– 3 regulations added after summary report submittal
• Obtain NRC feedback on proposed resolution for regulatory gaps
• Obtain NRC feedback on additional pre-application interactions planned for selected regulatory gaps
TMNonproprietary
© 2012 NuScale Power, LLC4
Background• Design-Specific Review Standard (DSRS) approach
(from SECY-11-0024)– update of introduction of Standard Review Plan (SRP) describing
risk-informed review and integrated review process
– DSRS contains selected sections modified for NuScale design
– DSRS references the unchanged SRP sections
• Pre-application outcomes (October 2011 meeting) – agreement on applicability of requirements and guidance
• Gap analysis process and scope presented (May 2012 meeting)
• Submitted gap analysis summary report (July 2012)
TMNonproprietary
© 2012 NuScale Power, LLC5
Background
DSRS & SRP
sections
Gap analysis summary report• Proposed DSRS section
roadmap• Regulatory gaps
Gap analysis tables in electronic reading room• Regulations• SRP acceptance criteria
and sub-tier guidance• Regulatory guides
Design description• Design overview• Categorization of
structures, systems, and components (SSCs)
Content outline(covered in DSRS engagement as
needed)
TMNonproprietary
© 2012 NuScale Power, LLC6
Gap Analysis Process – Scope• 10 CFR Parts 1 through 199, with particular focus on
– 10 CFR 52– 10 CFR Parts 20, 50, 51, 73, and 100 as specified in 10 CFR 52.48
• Standard Review Plan (NUREG-0800) including sub-tier guidance– regulatory guides (RGs), including RG 1.206– NUREGs– TMI requirements and unresolved / generic safety issues– NRC documents (SECYs and associated SRMs)– NRC generic communications – industry codes and standards
• Interim Staff Guidance relevant to applicants for design certification
• Regulatory guides – Division 1, 4, 5, and 8 in addition to RGs referenced in SRP
TMNonproprietary
© 2012 NuScale Power, LLC7
Gap Analysis Process – Regulations
Adequate level of safety
Functional purpose of
LWR requirements,
guidance
Functional purpose and
design criteria for NuScale
Compare
Existing regulation
applies
Existing regulation partially applies
Existing regulation does not
apply
NuScale unique feature/
requirement
Resolution
SMR reactor safety functions,
functional analysis,SSCs design criteria,
safety analysis, LBEs DID
Existing LWR requirements,
GDCs, guidance
SMR reactor design and PRA use
TMNonproprietary
© 2012 NuScale Power, LLC8
Gap Analysis Process – Regulations• Summary report identified17 regulations requiring further consideration
– Regulations that would not apply to NuScale as it would for current light-water reactor (LWR) designs
– Considering literal language of rule
• Design literally meets rule: specific approach warrants pre-application interaction
• Departures: Applicable to design certification or combined license application but not appropriate to apply to NuScale design
• Propose resolution taking into account
– regulatory intent
– NuScale design considerations
– regulatory history including statements of consideration
– regulatory precedent
• Feedback on proposed resolution to meet regulation or form of departure
TMNonproprietary
© 2012 NuScale Power, LLC9
Gap Analysis Results – Regulations Summary Table
Proposed resolution Future
engagement 10 CFR Subject
1 50.54(m)(2)(i) and (iii) Minimum Licensed Operator Staffing Requirements Exemption Y 2 50.62(c)(1) Reduction of Risk from ATWS Events Potential Exemption Y 3 50.44(c)(2) Combustible Gas Control Complies with rule Y 4 50, App. K ECCS Evaluation Models Complies with rule Y 5 50.34(f)(2)(vi) Reactor Coolant System Venting Complies with rule6 50.46a Reactor Coolant System Venting Complies with rule7 GDC 17 Electric power systems Departure Y 8 GDC 27 Combined reactivity control systems capability Departure9 GDC 33 Reactor coolant makeup / inventory control Departure Y 10 GDC 55 Containment isolation Departure Y 11 GDC 56 Containment isolation Departure Y 12 GDC 57 DHR / Containment isolation Departure Y 13 GDC 40 Testing of containment heat removal system Not applicable14 GDC 41 Containment atmosphere cleanup Complies with rule15 GDC 42 Inspection of containment atmosphere cleanup systems Not applicable16 GDC 43 Testing of containment atmosphere cleanup systems Not applicable17 50.34(f)(2)(xv) Containment Purging/Venting Capability and Isolation Not technically relevant18 50.34(f)(2)(xii) Auxiliary Feedwater System Actuation and Flow Indication Not technically relevant19 50.34(f)(1)(ii) Evaluation and Design Review of AFW System Not technically relevant20 50.34(f)(2)(iv) Safety Parameter Display System (SPDS) Complies with rule
Changed from gap analysis summary reportAdded to list in gap analysis summary report submittal
TMNonproprietary
© 2012 NuScale Power, LLC10
Gap Analysis Results – RegulationsFramework for presenting gaps• Regulatory requirement summary• Regulatory purpose• NuScale design considerations• Statement of regulatory gap• Pre-application plan
– proposed resolution
– future interactions
• Gap analysis impact
TMNonproprietary
© 2012 NuScale Power, LLC11
50.54(m)(2)(i), (iii) – Staffing Requirements
Regulatory Requirement Summary• Each licensee shall meet the minimum licensed operator staffing
requirements in the following table: [50.54(m)(2)(i)]
Pre-Application PlanProposed resolution: exemption required
• Define appropriate staffing requirements for NuScale design
Future interactions:• HFE Program Plan submittals
• Planned HFE workshops
TMNonproprietary
© 2012 NuScale Power, LLC12
50.62(c)(1) - Reduction of Risk from ATWS Events
Regulatory Requirement Summary and Purpose• Each pressurized water reactor must have equipment from sensor
output to final actuation device, that is diverse from the reactor trip system, to automatically initiate the auxiliary (or emergency) feedwater system and initiate a turbine trip under conditions indicative of an ATWS.
• ATWS rule was written for specific plant designs
NuScale Design Considerations• Have to consider AOOs, plant response, and I&C implementation
appropriate to address ATWS conditions for NuScale design
TMNonproprietary
© 2012 NuScale Power, LLC13
50.62(c)(1) Reduction of Risk from ATWS Events
Pre-Application PlanProposed resolution: Potential exemption required
• To be discussed in future pre-application interactions
Future interactions: Present ATWS approach as part of DSRS engagement on chapters 15.8 and 7
TMNonproprietary
© 2012 NuScale Power, LLC14
50.44(c)(2) – Combustible Gas Control
Regulatory Requirement Summary• All containments must have an inerted atmosphere, or
must limit hydrogen concentrations in containment …
Regulatory purpose• Section 50.44 provides requirements for the mitigation of
combustible gas generated by a beyond-design-basis accident.
TMNonproprietary
© 2012 NuScale Power, LLC15
50.44(c)(2) – Combustible Gas Control
NuScale Design Considerations
}}3(a)
• Convective mixing of containment atmosphere, no sub-compartments
{{
TMNonproprietary
© 2012 NuScale Power, LLC16
50.44(c)(2) – Combustible Gas Control
Statement of Regulatory Gap
{{
}}3(a)
Containment must have an inerted
atmosphereGAP?
TMNonproprietary
© 2012 NuScale Power, LLC17
50.44(c)(2) – Combustible Gas Control
Pre-Application PlanProposed resolution: no exemption required
}}3(a)
• Complying with portions of the rule that apply to inerted containments
Future interactions: Cover along with other requirements of 50.44 as part DSRS engagement on Chapter 6.2.5
{{
TMNonproprietary
© 2012 NuScale Power, LLC18
50.44(c)(2) – Combustible Gas Control
Gap Analysis Impact• Different approach from Gap Analysis Summary Report
– Previously proposed partial exemption for 10 CFR 50.44(c)(2)
• SRP sections that address rule– Section 6.2.5, “Combustible Gas Control in Containment”
– Section 3.8.1, “Concrete Containment”
– Section 3.8.2, “Steel Containment”
TMNonproprietary
© 2012 NuScale Power, LLC19
10 CFR 50, Appendix K – ECCS Evaluation Models
Regulatory Requirement Summary• 10 CFR 50.46: ECCS cooling performance during LOCAs
must be calculated with an acceptable evaluation model using either– a best-estimate evaluation model or
– a conservative evaluation model (10 CFR 50, Appendix K)
• Appendix K provides required and acceptable features of a conservative ECCS Evaluation Model for example– The rate of energy release… from the metal/water reaction shall
be calculated
– shall include a provision for predicting cladding swelling and rupture
TMNonproprietary
© 2012 NuScale Power, LLC20
10 CFR 50, Appendix K – ECCS Evaluation Models
NuScale Design Considerations• ECCS active components: vent valves and recirculation
valves• Containment wall facilitates ECCS heat removal • Core remains covered for design basis events - no large-
break LOCA• Integral reactor with no piping loops – no cold leg break• Natural circulation flow – no reactor coolant pump trip
TMNonproprietary
© 2012 NuScale Power, LLC21
10 CFR 50, Appendix K – ECCS Evaluation Models
Statement of Regulatory Gap
{{
}}3(a)
Appendix K identifies required and acceptable features of ECCS evaluation models for large PWRs
GAP?
TMNonproprietary
© 2012 NuScale Power, LLC22
10 CFR 50, Appendix K – ECCS Evaluation Models
Pre-Application PlanProposed resolution: No exemption required• NuScale ECCS evaluation models for small-break
LOCAs only need to address technically relevant features required by Appendix K
Future interactions: present implementation as part of DSRS engagement on Chapter 6.3
TMNonproprietary
© 2012 NuScale Power, LLC23
10 CFR 50, Appendix K – ECCS Evaluation Models
Precedent
• ABWR – SAFER application methodology - Appendix K peak cladding temperatures (PCT) calculated
compared to a statistically calculated 95% probability value
• ESBWR has no core uncovery– simplified statistical approach based on chimney height, not PCT
• AP1000 – voluntary use of statistical uncertainty analysis to justify relaxation of all but the required
conservatisms contained in current ECCS evaluation models
– small-break LOCA response using Appendix K
• EPR– methodology used to analyze LBLOCA is a best-estimate EM based on non-parametric
statistics.
– small-break LOCA response using Appendix K
TMNonproprietary
© 2012 NuScale Power, LLC24
10 CFR 50, Appendix K – ECCS Evaluation Models
Gap Analysis Impact • Gap Analysis Summary Report did not propose a
resolution for Appendix K• SRP sections that address rule
– Section 4.2, “Fuel System Design”
– Section 6.2.1.3, “Mass and Energy Release Analysis for Postulated Loss-of-Coolant Accidents (LOCAs)”
– Section 6.2.1.5, “Minimum Containment Pressure Analysis for Emergency Core Cooling System Performance Capability Studies”
– Section 6.3, “Emergency Core Cooling System”
– Section 15.0.2,” Review of Transient and Accident Analysis Method”
– Section 15.6.5, “Loss-of-Coolant Accidents Resulting From Spectrum of Postulated Piping Breaks Within the Reactor Coolant Pressure Boundary”
TMNonproprietary
© 2012 NuScale Power, LLC25
50.34(f)(2)(vi), 50.46a – Reactor Coolant System Vents
Regulatory Requirement Summary*
• Each reactor must provide high point vents for – the reactor coolant system (RCS)
– the reactor vessel head
– other systems required to maintain adequate core cooling if accumulation of noncondensible gases would cause loss of function of these systems
*Both 50.34(f)(2)(vi) and 50.46a are applicable to design certification applicants and are substantively similar
TMNonproprietary
© 2012 NuScale Power, LLC26
50.34(f)(2)(vi), 50.46a – Reactor Coolant System Vents
Regulatory Requirement Summary
• Design requirements– remotely operated from control room
– vents and associated components must meet GDCs and Appendix B
– designed to ensure • vents will perform safety functions
• no inadvertent or irreversible actuation of a vent
– operation shall not lead to unacceptable increase in probability of LOCA or challenge to containment integrity
TMNonproprietary
© 2012 NuScale Power, LLC27
50.34(f)(2)(vi), 50.46a – Reactor Coolant System Vents
Regulatory Purpose
• Accumulation of noncondensible gases in RCS could interfere with adequate core cooling
• Ability to vent gases supports long-term core cooling via natural or forced circulation
• Provides assurance that vents maintain reactor coolant pressure boundary integrity
TMNonproprietary
© 2012 NuScale Power, LLC28
50.34(f)(2)(vi), 50.46a – Reactor Coolant System Vents
• Integral reactor pressure vessel – core, steam generators, pressurizer
– the reactor vessel high point is also the RCS and pressurizer high point
– no other systems require venting to support core cooling
• ECCS reactor vent valves– at reactor vessel high point
– vent to containment
NuScale Design Considerations
Containment
Reactor vent valves
Reactor recirculation valves
TMNonproprietary
© 2012 NuScale Power, LLC29
50.34(f)(2)(vi), 50.46a – Reactor Coolant System Vents
NuScale Design Considerations• ECCS vent valves provide inherent RCS venting capability
– vent noncondensible gases to containment when ECCS actuated
– vented gasses will not interfere with ECCS cooling
– will not challenge containment integrity
• ECCS vent valves meet design requirements– safety-related system
– operable from control room
• Does not affect LOCA probability– no additional components or controls
– failure and inadvertent actuation are analyzed events
TMNonproprietary
© 2012 NuScale Power, LLC30
50.34(f)(2)(vi), 50.46a – Reactor Coolant System Vents
Statement of Regulatory Gap
ECCS valves serve as RCS high point vents in NuScale
design without separate vents
Must provide high point vents for
reactor, RCS, and other systems as
necessary
GAP?
TMNonproprietary
© 2012 NuScale Power, LLC31
50.34(f)(2)(vi), 50.46a – Reactor Coolant System Vents
Pre-Application PlanProposed resolution: no exemption required• NuScale ECCS vent valves meet requirement for high
point vents
Precedent:• BWRs: inherent venting capability via SRVs• AP1000: ADS first stage credited as pressurizer high
point vent
Future interactions: DSRS development only
TMNonproprietary
© 2012 NuScale Power, LLC32
50.34(f)(2)(vi), 50.46a – Reactor Coolant System Vents
Gap Analysis Impact
• Different approach from Gap Analysis Summary Report
– Previously proposed normal RPV vent line met literal language of high point vent rules, with no safety function related to core cooling
• SRP sections that address rule
– Section 5.4.12, “Reactor Coolant System High Point Vents”
TMNonproprietary
© 2012 NuScale Power, LLC33
Appendix A to Part 50
General Design Criteria for Nuclear Power Plants
TMNonproprietary
© 2012 NuScale Power, LLC34
GDC 17 – Electric Power SystemsRegulatory Requirement Summary
Electric power from the transmission network to the onsite electric distribution system shall be supplied by two physically independent circuits…designed and located so as to minimize to the extent practical the likelihood of their simultaneous failure under operating and postulated accident and environmental conditions.
TMNonproprietary
© 2012 NuScale Power, LLC35
Regulatory Purpose
• Ensure reliable power to accomplish safety functions
– SAFDLs and RCPB design conditions not exceeded as a result of AOOs
– core cooling, containment integrity, etc. maintained for postulated accidents
• Traditional LWRs require A/C power for safety system function
– either onsite or offsite A/C necessary
– independent offsite circuits increase reliability
GDC 17 – Electric Power Systems
TMNonproprietary
© 2012 NuScale Power, LLC36
GDC 17 – Electric Power SystemsNuScale Design Considerations
• A/C power not required for safe shutdown, core cooling, or containment integrity
}}3(a)
– nonsafety-related onsite and offsite power sources provided
• Redundant circuits from transmission network not necessary to ensure safety
{{
TMNonproprietary
© 2012 NuScale Power, LLC37
GDC 17 – Electric Power SystemsStatement of Regulatory Gap
NuScale design does not require
two offsite circuits
Two physically independent offsite
electrical power circuits required to
ensure safety functions are accomplished
GAP
TMNonproprietary
© 2012 NuScale Power, LLC38
GDC 17 – Electric Power SystemsPre-Application Plan
Proposed resolution: departure from GDC 17
• Design certification scope will include one offsite circuit
• Underlying purpose of the rule met without need for two offsite circuits
Precedent:• SECY-94-084: evaluate LOOP challenges against
coping capability
• AP1000 (exemption)
TMNonproprietary
© 2012 NuScale Power, LLC39
GDC 17 – Electric Power SystemsPre-Application Plan
• Future interactions:– Upcoming engagement on Class 1E power system approach
– Discuss departure implementation in DSRS Ch. 8 engagement
Gap Analysis Impact
• Identified in Gap Analysis Summary Report• SRP sections that address rule
– Section 8.2, “Offsite Power System”
– Section 8.3.1, “AC Power Systems (Onsite)”
TMNonproprietary
© 2012 NuScale Power, LLC40
GDC 27 – Reactivity Control SystemsRegulatory Requirement Summary
The reactivity control systems shall be designed to have a combined capability, in conjunction with poison addition by the emergency core cooling system, of reliably controlling reactivity changes to assure that under postulated accident conditions and with appropriate margin for stuck rods the capability to cool the core is maintained.
TMNonproprietary
© 2012 NuScale Power, LLC41
GDC 27 – Reactivity Control Systems
Regulatory Purpose• GDC 27 provides assurance reactor can be shut down
and core coolability maintained in event of an accident• “In conjunction with poison addition by the emergency
core cooling system” – large LWR ECCS inject large volumes of borated water to control
inventory
– any poison added by ECCS injection can be credited in accident response for meeting reactivity control
TMNonproprietary
© 2012 NuScale Power, LLC42
GDC 27 – Reactivity Control Systems
NuScale Design Considerations• ECCS has no makeup function
– no RCS inventory added by actuation– no poison addition via borated makeup
}}3(a)
{{
TMNonproprietary
© 2012 NuScale Power, LLC43
GDC 27 – Reactivity Control Systems
Statement of Regulatory Gap
{{
}}3(a)
GDC 27 includes “poison addition by the emergency core cooling system” among the reactivity control systems
GAP?
TMNonproprietary
© 2012 NuScale Power, LLC44
GDC 27 – Reactivity Control Systems
Pre-Application PlanProposed resolution: no departure required• NuScale design will meet regulatory requirements
}}3(a)
Future interactions: DSRS development only
{{
TMNonproprietary
© 2012 NuScale Power, LLC45
GDC 27 – Reactivity Control Systems
Gap Analysis Impact
• Different approach from Gap Analysis Summary Report based on design change
}}3(a)
• SRP sections that address rule
– Section 4.3, “Nuclear Design”
– Chapter 15, “Transient and Accident Analysis”
{{
TMNonproprietary
© 2012 NuScale Power, LLC46
GDC 33 – Reactor Coolant MakeupRegulatory Requirement Summary
A system to supply reactor coolant makeup for protection against small breaks in the reactor coolant pressure boundary shall be provided. The system safety function shall be to assure that specified acceptable fuel design limits (SAFDLs) are not exceeded….
TMNonproprietary
© 2012 NuScale Power, LLC47
GDC 33 – Reactor Coolant MakeupRegulatory Purpose
• Protection against small breaks in the RCPB
• Provide sufficient reactor coolant makeup capacity to maintain reactor coolant system (RCS) water inventory and prevent the violation of SAFDLs
TMNonproprietary
© 2012 NuScale Power, LLC48
GDC 33 – Reactor Coolant MakeupNuScale Design Considerations
• Reactor coolant from leaks and breaks is retained within containment vessel
• ECCS actuation returns water accumulated in containment vessel to the core through natural circulation
• Steam generator tube leaks are retained through feed and steam isolation
• For breaks inside containment, integrated module design– retains total reactor coolant inventory
– keeps core covered
– provides adequate core cooling
TMNonproprietary
© 2012 NuScale Power, LLC49
GDC 33 – Reactor Coolant MakeupNuScale Design Considerations
• Chemical and volume control (CVC) system provides nonsafety-related reactor coolant makeup and letdown capability
– accommodates minor RCS leakage during normal operation
– maintains level during reactor heatup and cooldown
– not relied upon to prevent core uncovery or provide core cooling in the event of a postulated leak or break in the RCPB
TMNonproprietary
© 2012 NuScale Power, LLC50
GDC 33 – Reactor Coolant MakeupStatement of Regulatory Gap
For small breaks, integral module
design with ECCS to retain reactor coolant inventory
For protection against small
breaks, makeup system required to
maintain core coolant inventory
and prevent violation of SAFDLs
GAP
TMNonproprietary
© 2012 NuScale Power, LLC51
GDC 33 – Reactor Coolant MakeupPre-Application Plan
Proposed resolution: departure from GDC 33• alternative design-specific principal design criterion
– assurance of adequate reactor coolant inventory
Precedent:• Safety evaluation report for Clinch River Breeder Reactor (NUREG-0968)
• Pre-application safety evaluation report for PRISM (NUREG-1368)
Future interactions: present implementation as part of DSRS engagement on Chapter 9
TMNonproprietary
© 2012 NuScale Power, LLC52
GDC 33 – Reactor Coolant MakeupGap Analysis Impact
• Identified in Gap Analysis Summary Report
• SRP sections that address rule
– Section 9.3.4, “Chemical and Volume Control System”
TMNonproprietary
© 2012 NuScale Power, LLC53
GDCs 55, 56 – Containment Isolation
Regulatory Requirement Summary
• Each line that is part of RCPB (GDC 55) or connectsdirectly to containment atmosphere (GDC 56) must havetwo containment isolation valves (CIVs), in series– combinations of locked closed and/or automatic CIVs, (simple
check valves allowed only inside containment)
– one inside and one outside containment
– outside valve “as close to containment as practical”
– take position of greater safety upon loss of power
TMNonproprietary
© 2012 NuScale Power, LLC54
GDCs 55, 56 – Containment Isolation
Regulatory Requirement Summary
• Additional provisions– Allows for “demonstrat[ion] that the containment isolation
provisions for a specific class of lines . . . are acceptable on someother defined basis”• SRP 6.2.4 accepts some other configurations with criteria and
requirements (instrument lines, ESF, and safe shutdown lines)
– “Other appropriate requirements to minimize the probability orconsequences of an accidental rupture…shall be provided asnecessary to assure adequate safety.” (GDC 55 only)
TMNonproprietary
© 2012 NuScale Power, LLC55
GDCs 55, 56 – Containment Isolation
Regulatory Purpose
• Allow normal or emergency fluid passage through containment boundary while preserving ability to limit escape of fission products from postulated accidents
• Provisions are intended to increase isolation reliability
– two-barrier philosophy to account for single failure
– diverse locations (leakage inside containment, common-cause failure of both CIVs)
– prescriptive requirements draw from large LWR experience (many penetrations, large valves, normal containment leakage)
TMNonproprietary
© 2012 NuScale Power, LLC56
GDCs 55, 56 – Containment Isolation
NuScale Design Considerations }}3(a)
• Small lines and isolation valves• Very low-leakage containment vessel• Harsh containment vessel (CNV) conditions
}}3(a)
{{
{{
TMNonproprietary
© 2012 NuScale Power, LLC57
GDCs 55, 56 – Containment Isolation
NuScale Design Considerations• Proposed design: {{
}}3(a)
TMNonproprietary
© 2012 NuScale Power, LLC58
GDCs 55, 56 – Containment Isolation
NuScale Design Considerations
}}3(a)
{{
TMNonproprietary
© 2012 NuScale Power, LLC59
GDCs 55, 56 – Containment Isolation
Statement of Regulatory Gap
{{
}}3(a)
GDCs 55 and 56 require one CIV inside containment and one outside containment
GAP
TMNonproprietary
© 2012 NuScale Power, LLC60
GDC 57 – Containment Isolation
Regulatory Requirement Summary
• GDC 57 “closed system”
– line penetrating containment that is not part of RCPB and notconnected directly to containment atmosphere
• Must have– one containment isolation valve outside containment
– locked closed, automatic, or remote manual
– located “as close to containment as practical”
TMNonproprietary
© 2012 NuScale Power, LLC61
GDC 57 – Containment Isolation
Regulatory Purpose
• Same purpose as GDCs 55 and 56.
• Follows the same “two isolation barrier” approach– for closed systems, first barrier is the closed system itself
– failures must occur in system inside containment and the CIV forrelease outside containment
TMNonproprietary
© 2012 NuScale Power, LLC62
GDC 57 – Containment Isolation
• Most closed systems will meet GDC 57 (MS and FW)
}}3(a)
NuScale Design Considerations
{{
TMNonproprietary
© 2012 NuScale Power, LLC63
GDC 57 – Containment Isolation
Statement of Regulatory Gap
{{
}}3(a)
GDC 57 requires one CIV outside containment
GAP
TMNonproprietary
© 2012 NuScale Power, LLC64
GDCs 55-57 – Containment Isolation
Pre-Application PlanProposed resolution: departures from GDCs 55, 56 & 57
}}3(a)
– detailed design information required to support departures
Future interactions: specific engagement as design progresses
{{
TMNonproprietary
© 2012 NuScale Power, LLC65
GDCs 55-57 – Containment Isolation
Gap Analysis Impact
• Not addressed in Gap Analysis Summary Report
– new gap due to design progression
• SRP sections that address rule
– Section 6.2.4, “Containment Isolation System”
TMNonproprietary
© 2012 NuScale Power, LLC66
GDC 40 – Testing of Containment Heat Removal System
Regulatory Requirement SummaryThe containment heat removal system shall be designed to permit appropriate periodic pressure and functional testing to assure (1) the structural and leaktight integrity of its components, (2) the operability and performance of the active components of the system, and (3) the operability of the system as a whole…
TMNonproprietary
© 2012 NuScale Power, LLC67
GDC 40 – Testing of Containment Heat Removal System
Regulatory Purpose• Ensures reliable performance of containment heat
removal system (required by GDC 38)
• Contemplates testing of active systems such as
– containment spray system
– fan cooler system
TMNonproprietary
© 2012 NuScale Power, LLC68
GDC 40 – Testing of Containment Heat Removal System
NuScale Design Considerations • No active containment heat removal system as
contemplated by GDC 40– containment vessel submerged in the reactor pool (UHS)
– heat removal by passive heat transfer through the containment vessel steel walls
– no reliance on electrical power, valve actuation, cooling water flow, or other active systems or components
• Passive heat removal performance established as part of design and test program for design certification
TMNonproprietary
© 2012 NuScale Power, LLC69
GDC 40 – Testing of Containment Heat Removal System
Statement of Regulatory Gap
NuScale design has no active
containment heat removal systems
The containment heat removal
system shall be designed to permit
appropriate periodic pressure
and functional testing
GAP
TMNonproprietary
© 2012 NuScale Power, LLC70
GDC 40 – Testing of Containment Heat Removal System
Pre-Application PlanProposed resolution: no departure required• GDC 40 does not apply to the NuScale design
Future interactions: DSRS development only
TMNonproprietary
© 2012 NuScale Power, LLC71
GDC 40 – Testing of Containment Heat Removal System
Gap Analysis Impact
• Identified in Gap Analysis Summary Report
• SRP sections that address rule– Section 6.2.2, “Containment Heat Removal Systems”
TMNonproprietary
© 2012 NuScale Power, LLC72
GDC 41 – Containment Atmosphere Cleanup
Regulatory Requirement Summary
Systems to control fission products, hydrogen, oxygen, and other substances which may be released into the reactor containment shall be provided as necessary to
• reduce… the concentration and quality of fission products released to the environment following postulated accidents
• control the concentration of hydrogen or oxygen and other substances in the containment atmosphere following postulated accidents to assure that containment integrity is maintained
TMNonproprietary
© 2012 NuScale Power, LLC73
GDC 41 – Containment Atmosphere CleanupRegulatory Purpose
• Provide for containment atmosphere cleanup systems “as necessary” to
– reduce fission product release from containment leakage
– reduce hydrogen or oxygen if required to protect containment integrity from hydrogen combustion
• Contemplates systems such as
– containment spray system
– engineered safety feature (ESF) ventilation filtration system
– hydrogen igniters and hydrogen and oxygen monitors
TMNonproprietary
© 2012 NuScale Power, LLC74
GDC 41 – Containment Atmosphere Cleanup
NuScale Design Considerations
• Fission product release passively controlled by– reactor module configuration
– containment vessel design leakage rate
• Containment integrity assured by – robust containment vessel design
– low oxygen content
• Systems to control fission products and combustible gasses not anticipated to be necessary
TMNonproprietary
© 2012 NuScale Power, LLC75
GDC 41 – Containment Atmosphere Cleanup
Statement of Regulatory Gap
Containment atmosphere
cleanup systems are not necessary
for NuScale design
Containment atmosphere
cleanup systems shall
be provided as necessary…
GAP?
TMNonproprietary
© 2012 NuScale Power, LLC76
GDC 41 – Containment Atmosphere Cleanup
Pre-Application Plan
Proposed resolution: no departure required
• absence of atmosphere cleanup systems in the NuScale design is consistent with the “as necessary” provision of GDC 41
Precedent: AP1000 similar approach (fission products)
Future interactions: DSRS development only
TMNonproprietary
© 2012 NuScale Power, LLC77
GDC 41 – Containment Atmosphere Cleanup
Gap Analysis Impact
• Identified in Gap Analysis Summary Report
• Related SRP sections
– Section 6.2.5, “Combustible Gas Control in Containment”
– Section 6.5.1, “ESF Atmosphere Cleanup Systems”
– Section 6.5.2, “Containment Spray as a Fission Product Cleanup System”
– Section 6.5.3, “Fission Product Control Systems and Structures”
– Section 6.5.5, “Pressure Suppression Pool as a Fission Product Cleanup System”
TMNonproprietary
© 2012 NuScale Power, LLC78
GDCs 42 and 43 – Inspection and Testing of Containment Atmosphere Cleanup Systems
Regulatory Requirement Summary
The containment atmosphere cleanup systems shall be designed to permit appropriate periodic• inspection of important components...to assure the
integrity and capability of the systems. [GDC 42]• pressure and functional testing to assure structural and
leak-tight integrity of components, operability and performance of active components, and operability of the systems as a whole. [GDC 43]
TMNonproprietary
© 2012 NuScale Power, LLC79
GDCs 42 and 43 – Inspection and Testing of Containment Atmosphere Cleanup Systems
Regulatory Purpose
• Ensures performance and reliability of containment atmosphere cleanup systems provided to meet GDC 41
• Contemplates systems such as
– containment spray system and pressure suppression devices
– ESF ventilation filtration system
– hydrogen igniters and hydrogen and oxygen monitors
TMNonproprietary
© 2012 NuScale Power, LLC80
GDCs 42 and 43 – Inspection and Testing of Containment Atmosphere Cleanup Systems
Statement of Regulatory Gap
Containment atmosphere
cleanup systems are not included in
the NuScale design
Containment atmosphere
cleanup systems shall
be designed to permit inspection
and testing
GAP?
TMNonproprietary
© 2012 NuScale Power, LLC81
GDCs 42 and 43 – Inspection and Testing of Containment Atmosphere Cleanup Systems
Pre-Application PlanProposed resolution: no departure required
• Do not anticipate the need for atmosphere cleanup systems per GDC 41
• GDCs 42 and 43 do not apply to NuScale design
Precedent: AP1000
Future interactions: DSRS development only
TMNonproprietary
© 2012 NuScale Power, LLC82
GDCs 42 and 43 – Inspection and Testing of Containment Atmosphere Cleanup Systems
Gap Analysis Impact
• Identified in Gap Analysis Summary Report
• Related SRP sections
– Section 6.2.5, “Combustible Gas Control in Containment”
– Section 6.5.1, “ESF Atmosphere Cleanup Systems”
– Section 6.5.2, “Containment Spray as a Fission Product Cleanup System”
– Section 6.5.3, “Fission Product Control Systems and Structures”
– Section 6.5.5, “Pressure Suppression Pool as a Fission Product Cleanup System”
– Section 6.6, “Inservice Inspection and Testing of Class 2 and 3 Components”
TMNonproprietary
© 2012 NuScale Power, LLC83
50.34 – Contents of applications; technical information
(f) Additional TMI-related requirements
TMNonproprietary
© 2012 NuScale Power, LLC84
50.34(f)(2)(xv) – Containment PurgingRegulatory Requirement Summary
Provide a capability for containment purging/venting designed to minimize the purging time consistent with ALARA principles for occupational exposure.
Provide and demonstrate high assurance that the purge system will reliably isolate under accident conditions.
TMNonproprietary
© 2012 NuScale Power, LLC85
50.34(f)(2)(xv) – Containment PurgingRegulatory Purpose
• Large LWRs: containment personnel access during operations necessitates containment purging/venting
• Post-TMI concern over radiological consequences of containment purging/venting
– balance occupational and public exposure from normal purging
– risk of accident while purging system open
• Requires actions to restrict purging/venting and reliably isolate on demand
TMNonproprietary
© 2012 NuScale Power, LLC86
50.34(f)(2)(xv) – Containment PurgingNuScale Design Considerations
• No containment purging/venting system as contemplated by rule– Compact containment vessel does not allow for personnel access
during operation
– Containment only opened during cold shutdown
– NuScale containment remains sealed during operations, no direct path to the environs
TMNonproprietary
© 2012 NuScale Power, LLC87
50.34(f)(2)(xv) – Containment PurgingStatement of Regulatory Gap
NuScale design does not include a
purging/venting system
Provide purging designed to
minimize purging time, reliable
isolation
GAP?
TMNonproprietary
© 2012 NuScale Power, LLC88
50.34(f)(2)(xv) – Containment PurgingPre-Application Plan
Proposed resolution: no exemption required• Containment purging/venting requirements are not
technically relevant to NuScale design
Future interactions: DSRS development only
TMNonproprietary
© 2012 NuScale Power, LLC89
50.34(f)(2)(xv) – Containment PurgingGap Analysis Impact
• Identified in Gap Analysis Summary Report
• SRP sections that address rule
– Section 6.2.4, “Containment Isolation System”
– BTP 6-4, “Containment Purging During Normal Plant Operations”
TMNonproprietary
© 2012 NuScale Power, LLC90
50.34(f)(2)(xii) – AFW System Actuation and Flow Indication
Regulatory Requirement Summary Provide automatic and manual auxiliary feedwater (AFW) system initiation, and provide auxiliary feedwater system flow indication in the control room (TMI Action Item II.E.1.2)
TMNonproprietary
© 2012 NuScale Power, LLC91
50.34(f)(2)(xii) – AFW System Actuation and Flow Indication
Regulatory Purpose• Ensure timely initiation of the AFW system with loss of feedwater
(GDC 20)
• Provide instrumentation and controls for direct verification of AFW system performance (GDC 13)
NuScale Design Considerations• NuScale design does not include an AFW system
TMNonproprietary
© 2012 NuScale Power, LLC92
50.34(f)(2)(xii) – AFW System Actuation and Flow Indication
Statement of Regulatory Gap
NuScale design does not include an AFW system
PWR designs are required to have automatic and manual AFW
system initiation and AFW system flow indication in the control room
GAP
TMNonproprietary
© 2012 NuScale Power, LLC93
50.34(f)(2)(xii) – AFW System Actuation and Flow Indication
Pre-Application PlanProposed resolution: no exemption required• 50.34(f)(2)(xii) is not technically relevant to NuScale
designFuture interactions: DSRS development only
TMNonproprietary
© 2012 NuScale Power, LLC94
50.34(f)(2)(xii) – AFW System Actuation and Flow Indication
Gap Analysis Impact• Different approach from Gap Analysis Summary Report
– Previously proposed AFW requirement would apply to DHR
– DHR actuation and indication designed will be for NuScale-specific transients and system characteristics
• SRP sections that address rule– DSRS Section 7.2, “System Characteristics”
– Section 10.4.9, “Auxiliary Feedwater System (PWR)”
– Chapter 15, “Transient and Accident Analysis”
TMNonproprietary
© 2012 NuScale Power, LLC95
50.34(f)(1)(ii) – Auxiliary Feedwater Design Evaluation
Regulatory Requirement SummaryPerform an evaluation of the proposed auxiliary feedwater
system (AFWS), to include (applicable to PWRs only): (A) A simplified AFWS reliability analysis using event-tree
and fault-tree logic techniques. (B) A design review of AFWS.(C)An evaluation of AFWS flow design bases and criteria.
TMNonproprietary
© 2012 NuScale Power, LLC96
50.34(f)(1)(ii) – Auxiliary Feedwater Design Evaluation
Regulatory Purpose• Post-TMI requirement to ensure reliable AFW capability
for large PWRs• Reliability requirement based on CE, B&W, and
Westinghouse plant-specific design bases • Design basis functions were intended to prevent and
mitigate small-break loss-of-coolant accidents (LOCAs)
NuScale Design Considerations• NuScale design does not include an AFW system
TMNonproprietary
© 2012 NuScale Power, LLC97
50.34(f)(1)(ii) – Auxiliary Feedwater Design Evaluation
Statement of Regulatory Gap
NuScale design does not include an AFW system
Perform an evaluation of the
proposed auxiliary feedwater system
GAP?
TMNonproprietary
© 2012 NuScale Power, LLC98
50.34(f)(1)(ii) – Auxiliary Feedwater Design Evaluation
Pre-Application PlanProposed resolution: no exemption required• 50.34(f)(1)(ii) is not technically relevant to NuScale
designFuture interactions: none anticipated
TMNonproprietary
© 2012 NuScale Power, LLC99
50.34(f)(1)(ii) – Auxiliary Feedwater Design Evaluation
Gap Analysis Impact• Different approach from Gap Analysis Summary Report
– Previously proposed AFW requirement would apply to DHR
• SRP sections that address rule– Section 10.4.9, “Auxiliary Feedwater System (PWR)”
– Chapter 15, “Transient and Accident Analysis”
TMNonproprietary
© 2012 NuScale Power, LLC100
50.34(f)(2)(iv) – Safety Parameter Display System
Regulatory Requirement SummaryProvide a plant safety parameter display console that will display to operators a minimum set of parameters defining the safety status of the plant, capable of displaying a full range of important plant parameters and data trends on demand, and capable of indicating when process limits are being approached or exceeded.
TMNonproprietary
© 2012 NuScale Power, LLC101
50.34(f)(2)(iv) – Safety Parameter Display System
Regulatory Purpose• Post-TMI requirement to ensure reliable data capability
for operators• New consoles were necessary for existing plants• Most newer plants have integrated safety parameter
display system (SPDS) capabilities into the control room design and displays
TMNonproprietary
© 2012 NuScale Power, LLC102
50.34(f)(2)(iv) – Safety Parameter Display System
NuScale Design Considerations• The NuScale SPDS will be integrated into the control
room human-system interface design• Dedicated SPDS display, but not a physically separate
SPDS console
TMNonproprietary
© 2012 NuScale Power, LLC103
50.34(f)(2)(iv) – Safety Parameter Display System
Statement of Regulatory Gap
The NuScale design does not
include a separate SPDS console
Provide a plant safety parameter
display console. . .GAP?GAP?
TMNonproprietary
© 2012 NuScale Power, LLC104
50.34(f)(2)(iv) – Safety Parameter Display System
Pre-Application PlanProposed resolution: no exemption required• Rule does not require a separate, stand-alone SPDS
console• 10 CFR 50.34(f)(2)(iv) is applicable and NuScale design
meets regulatory requirementsPrecedent: EPR (pending)
Future interactions: DSRS development only
TMNonproprietary
© 2012 NuScale Power, LLC105
50.34(f)(2)(iv) – Safety Parameter Display System
Gap Analysis Impact
• Identified in Gap Analysis Summary Report
• SRP sections that address rule– Section 7.0, “Instrumentation and Controls - Overview of Review Process”
– Section 7.5, “Information Systems Important to Safety”
– Section 13.3, “Emergency Planning”
– Section 18, “Human Factors Engineering”
TMNonproprietary
© 2012 NuScale Power, LLC106
SummaryRegulations that do not require departures• Design meets rule (9): specific approach warrants pre-application
interaction
• Not applicable (3): requirements addressing systems or features that are not present in the NuScale design
Departures from regulatory requirements• Exemptions (2): design does not literally meet regulatory requirement
• Other departures (6): GDCs or specific aspect of GDC that are not appropriate to apply to the NuScale design
– identify and justify departure in NuScale FSAR (i.e., DCD)
– consistent with introduction in 10 CFR 50, Appendix A
– no exemption required under 10 CFR 52.7 and 10 CFR 50.12
TMNonproprietary
© 2012 NuScale Power, LLC107
Summary Table
Changed from gap analysis summary reportAdded to list in gap analysis summary report submittal
Proposed resolution Future
engagement 10 CFR Subject
1 50.54(m)(2)(i) and (iii) Minimum Licensed Operator Staffing Requirements Exemption Y 2 50.62(c)(1) Reduction of Risk from ATWS Events Potential Exemption Y 3 50.44(c)(2) Combustible Gas Control Complies with rule Y 4 50, App. K ECCS Evaluation Models Complies with rule Y 5 50.34(f)(2)(vi) Reactor Coolant System Venting Complies with rule6 50.46a Reactor Coolant System Venting Complies with rule7 GDC 17 Electric power systems Departure Y 8 GDC 27 Combined reactivity control systems capability Departure9 GDC 33 Reactor coolant makeup / inventory control Departure Y 10 GDC 55 Containment isolation Departure Y 11 GDC 56 Containment isolation Departure Y 12 GDC 57 DHR / Containment isolation Departure Y 13 GDC 40 Testing of containment heat removal system Not applicable14 GDC 41 Containment atmosphere cleanup Complies with rule15 GDC 42 Inspection of containment atmosphere cleanup systems Not applicable16 GDC 43 Testing of containment atmosphere cleanup systems Not applicable17 50.34(f)(2)(xv) Containment Purging/Venting Capability and Isolation Not technically relevant18 50.34(f)(2)(xii) Auxiliary Feedwater System Actuation and Flow Indication Not technically relevant19 50.34(f)(1)(ii) Evaluation and Design Review of AFW System Not technically relevant20 50.34(f)(2)(iv) Safety Parameter Display System (SPDS) Complies with rule
TMNonproprietary
© 2012 NuScale Power, LLC108
Feedback and Next Steps• 11 regulatory gaps require no further pre-application
discussion• 9 regulatory gaps are subjects of ongoing or future pre-
application discussions• Schedule for future interactions