PNP 2014-063, Response to Request for Additional Information License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactors
| ML14169A046 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/17/2014 |
| From: | Vitale A Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PNP 2014-063 | |
| Download: ML14169A046 (21) | |
Text
- Entergy Entergy Entergy Nuclear Nuclear Operations, Operations, Inc Inc..
Palisades Palisades Nuclear Nuclear Plant Plant 27780 Blue 27780 Blue Star Star Memorial Memorial Highway Highway Covert, MI 49043-9530
~ Entergy 4:o953o Tel 269 764 2000 Anthony JJ Vitale Anthony Vitale Site Vice President Site Vice President PNP 2014-063 PNP 201 4-063 17, 2014 June 17, Nuclear Regulatory Commission U. S. Nuclear ATTN: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Response to Request for Additional Information - License Amendment Performance-Based Standard for Fire Request to Adopt NFPA 805 Performance-Based Protection for Light Water Reactors Palisades Nuclear Plant Docket 50-255 License No. DPR-20
References:
- 1. ENO letter, PNP 2012-106, "License License Amendment Request to Adopt Performance-Based Standard for Fire Protection for Light NFPA 805 Performance-Based Water Reactors,"
Reactors, dated December 12, 2012 (ADAMS Accession Number ML ML12348A455) 12348A455)
- 2. ENO letter, PNP 2013-013, Response "Response to Clarification Request-Request License Amendment Request to Adopt NFPA 805 Performance-Based Performance-Based Standard for Fire Protection for Light Water Reactors,"
Reactors, dated February 21, 2013 (ADAMS Accession Number ML13079A090)
- 3. NRC electronic mail of August 8, 2013, Palisades "Palisades - Requests for Additional Information Regarding Transition to the Fire Protection Program to NFPA Standard 805 (TAC No. MF0382) MF0382)" (ADAMS Accession Number Number ML13220B131)
- 4. ENO
- 4. ENO letter, letter, PNP PNP 2013-075, 2013-075, Response "Response to to Request Request for for Additional Additional Information Information - License License Amendment Request to Adopt NFPA NFPA 805805 Performance -Based Standard Performance-Based Standard for Fire Protection for Light Water Reactors, Reactors", dated dated September September 30, 2013 (ADAMS 30,2013 (ADAMS Accession Number Number MLI 3273A469)
- 5. ENO
- 5. ENO letter, letter, PNP PNP 2013-079, 2013-079, Response "Response to to Request Request for for Additional Information Information - License License Amendment Request Request to to Adopt Adopt NFPANFPA 805805 Performance -Based Standard Performance-Based Standard for for Fire Fire Protection Protection for for Light Light Water Water Reactors, Reactors", dated dated October October 24, 2013 (ADAMS 24,2013 (ADAMS Accession Accession Number Number ML1 3298A044)
PNP 2014-063 PNP 2014-063 Page of 33 Page 22 of
- 6. ENO
- 6. END letter, letter, PNP PNP 2013-083, 2013-083, "Response Response to to Request Request for for Additional Additional Information - License Information License Amendment Amendment Request Request to Adopt NFPA to Adopt NFPA 805805 Performance-Based Standard Performance-Based Standard for for Fire Fire Protection Protection for for Light Light Water Water Reactors, dated Reactors", dated December December 2, 2, 2013 2013 (ADAMS (ADAMS Accession Accession Number Number ML113336A649)
ML 3336A649)
NRC electronic mail of
- 7. NRC of March March 11,2014, 11, 2014, "Requests Requests for Additional Information - Palisades - NFPA Information NFPA 805 Project Project LAR LAR - MF0382"
- MF0382 (ADAMS (ADAMS Accession NumberNumber ML ML141 18A293) 14118A293)
END letter, PNP 2014-035,
- 8. ENO 20 14-035, "Revised Revised Response to Request for Additional Information - License Amendment Request to Adopt NFPA Performance-Based Standard for Fire Protection for Light Water 805 Performance-Based Reactors, Reactors", dated April 2, 2014 END letter, PNP 2014-050, "Response
- 9. ENO Response to Request for Additional Information - License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Performance-Based Reactors, dated May 7,2014 Reactors", 7, 2014
- 10. NRC electronic mail of May 21, 2014, "Requests
- - MF0382 (ADAMS Accession Number ML ML14142A114142A104) 04)
Dear Sir or Madam:
Madam:
In Reference 1, 1, Entergy Nuclear Nuclear Operations, Operations, Inc. (END) (ENO) submitted a license amendment amendment requestrequest to adopt adopt thethe NFPA NFPA 805 805 performance performance-based-based standard standard for fire protection for light light water reactors. In In Reference 2, 2, ENO ENO responded to aa clarification clarification request.
request. In In Reference Reference 3, 3, END ENO received electronic electronic mailmail Request Request for for Additional Additional Information Information (RAls).
(RAls). In In Reference Reference 4, ENO submitted 4, ENO submitted thethe 60-day 60-day RAI RAI responses.
responses. In In Reference Reference 5, 5, END ENO submitted submitted the the revised revised 90-day 90-day RAIRAI responses. In In Reference Reference 6, 6, END ENO submitted the 120-day submitted the 120-day RAI RAI responses. In Reference In Reference 7, 7, END ENO received received electronic electronic mail mail RAts RAls on on Fire Fire Modeling.
Modeling. In In Reference Reference 8, 8, END ENO submitted submitted the the revised revised response response to to RAI RAI SSA SSA 07.
- 07. InIn Reference Reference 9, 9, END END submitted submitted responses responses to to the Fire Modeling the Fire Modeling RAls. RAls. In In Reference Reference 10, 10, END ENO received received electronic electronic mailmail RAts RAls onon Fire Fire PRA.
PRA. Per Per discussion discussion with with the the
- NRC, NRC, the the RAI RAI response response schedule schedule for the RAls for the RAls in in Reference Reference 10 10 is is as as follows:
follows:
PRA PRA RAls RAls duedue inin 30 30 days days (no(no later later than than June June 20,20, 2014):
2014):
.k.01, ,
PRA PRA 01 .mm.01, PRA 01.mm.01, PRA 01 .q.01, PRA 01.q.01, PRA 01 .r.01, PRA 01.r.01, PRA 01 .y.01, PRA 01.y.01, PRA 12.01,12.01, PRA PRA 31 31
PNP 2014-063 PNP 2014-063 Page Page 33 of of 33 PRA RAls PRA RAIs duedue in in 90 90 days days (no later than (no later than August August 19,19, 2014):
2014):
- PRAO1.j.01, PRA PRAO1.LO1 01.j.01, PRA PRA 17.b.01, 01.1.01,, PRA 17.b.01, PRA PRA2O.01, PRA23.01, 20.01, PRA 23.01, PRA 23.a.01, PRA PRA 23.a.01, PRA 23.c.01, 23.c.01, PRA PRA 28.a.01, 28.a.01, PRA PRA 3030 In Attachment 1, In ENO is 1, END is providing providing 30-day 30-day responses responses to to the RAIs noted the RAls noted above.
above.
A copy of this response of this response has has been been provided provided to to the the designated representative representative of of the the State State of Michigan.
This letter contains no new commitments This commitments and no revisions to existing commitments.
commitments.
I declare under penalty of perjury that the foregoing is true and correct. Executed on June 17, 2014.
Sincerely, ajv/jpm ajv/jpm
Attachment:
- 1. Response to Request for Additional Information Regarding License Amendment 1.
Request to Adopt NFPA 805 Performance -Based Standard for Fire Protection for Performance-Based Light Water Reactors cc: Administrato Administrator, r, Region Ill, III, USNRC USNRC Project Project Manager, Manager, Palisades, Palisades, USN USNRCRC Resident Inspector, Palisades, Inspector, Palisades, USNRC USNRC State State of of Michigan Michigan
ATTACHMENT 11 ATTACHMENT RESPONSE TO RESPONSE TO REQUEST REQUEST FOR FOR ADDITIONAL ADDITIONAL INFORMATION INFORMATION REGARDING LICENSE REGARDING LICENSE AMENDMENT AMENDMENT REQUEST REQUEST TO TO ADOPT ADOPT NFPA NFPA 805805 PERFORMA NCE-BASED PERFORMANCE-BASED STANDARD STANDARD FOR FOR FIRE FIRE PROTECTION PROTECTION FOR FOR LIGHT WATER LIGHT WATER REACTORS REACTORS NRC REQUEST NRC REQUEST PRA RAI01.e.01 PRA RAI O1.e.O1 The response The response to PRA RAJ to PRA RAI 01.e, 01.e, in in the the letter letter dated December 2, dated December 2, 2013, 2013, Agencywide Agencywide Documents Access and Documents Access and Management Management System System (ADAMS)
(ADAMS) Accession Accession No. No. ML ML13336A649, 13336A649, stated that stated that the the primary primary coolant coolant pump pump (PCP)(PCP) seal seal failure failure model model usedused the the methodology methodology presented in presented in WCAP-15749-P, WCAP- 15749-P, Revision Revision 1, 1, IIGuidance Guidance for for the the Implementation Implementation of of the the Combustion Engineering Combustion Engineering Owners Owners Group Group (CEOG)
(CEOG) Model for Failure Failure of of Reactor Coolant Coolant Pump Seals Pump Seals Given Given Loss of Seal Cooling Cooling (Task 2083)':2083), December 2008. This This topical has not has not been been endorsed endorsed by by the NRC.
NRC.
Describe whether Describe whether the PCP seal failure is the same for both the compliant and the post-transition transition PRAPRA models such that the impact of this model on the change in risk estimates is estimates is minimal.
minimal. If the PCP seal model differs between the compliant and post-transition PRA transition PRA models, or if the model has a substantive impact on the change in risk estimates, provide estimates, provide a summary of the method and the quantitative results that are used in the PRA.
in the PRA.
ENO RESPONSE ENO RESPONSE The The primary coolant pump seal failure model is based on the topical report generated generated by the owners the owners groupgroup and endorsed by the NRC (WCAP-161 (WCAP-16175-P-A). 75-P-A).
As As part part ofof a model model update the revised topical report report WCAP-1574 WCAP-15749-P, was reviewed 9-P, was reviewed for impact impact on on the the implementat implementation ion of of the the seal seal model.
model. WCAP-1 WCAP-15749-P 5749-P provides provides guidance guidance on on implementati implementation of on of the seal model model as as developed developed per per WCAP-1 6175-P-A. The WCAP-16175-P-A. The review of of WCAP-1574 WCAP-15749-P 9-P documented documented that that no no changes changes to to the the existing existing sealseal model model were were required required and none and none werewere made.
made.
Therefore, Therefore, the the existing existing seal seal model model remains remains consistent consistent with with thethe consensus consensus model model as as endorsed by the NRC as documented endorsed by the NRC as documented in in WCAP-1617 WCAP-16175-P-A. 5-P-A.
The The seal seal model model incorporated incorporated into into the the PRAPRA model model consists consists of of two two principal principal elements.
elements.
The first element is development The first element is development and and incorporation incorporation of of seal seal failure failure probabilities probabilities into into the the PRA PRA model.
model. The The second second element element includes includes the the plant plant specific specific elements elements with with respect respect toto maintaining seal cooling, instrument maintaining seal cooling, instrument and and control control related related to to primary primary coolant coolant pump pump operation operation and and the the human human error error probability probability for for failure failure toto trip trip the the primary primary coolant coolant pumps.
pumps.
Page Page 11 of of 18 18
The seal The seal failure failure probabilities probabilities were were developed developed per per and and remain remain consistent consistent with with thethe criteria criteria ofof WCAP-16175-P-A.
WCAP-1 6175-P-A. The The probability probability of of seal seal failure failure based based on the seal model is the on the seal model is the same for same for both both thethe compliant compliant and and post-transition post-transition plant. plant. TheThe probability probability of of seal seal failure failure was was not altered not altered in in the the post post transition transition plantplant results.
results.
The probability The probability of of failure failure of of support support systems systems required required for for seal seal cooling cooling and and instrument instrument and control and control necessary necessary to trip the to trip the pumps pumps is is aa plant plant specific specific input input to the PRA model to the PRA model logic logic and is not governed and is not governed by by the the consensus consensus model. model. This This element element of of the the model model is is based based on on plant specific plant specific features features with with oneone exception.
exception. The The human human errorerror probability probability for tripping for tripping the the primary coolant primary coolant pumps pumps is is based based on on the the time time available available to to accomplish accomplish the the action action defined defined by WCAP-16175-P-A.
by WCAP-1 6175-P-A.
Modification S2-5 Modification S2-5 (Provide (Provide Alternate Alternate Method Method of of Tripping Tripping Primary Primary Coolant Coolant PumpsPumps duringduring Fire Event)
Fire Event) as as described in in Attachment STable S Table S-2 S-2 of the original original PNP PNP LAR is LAR is beingbeing implemented as part implemented part of of transition to NFPA 805. This modification modification will will provide provide an alternate capability to trip the primary coolant pumps from the control room.
alternate Implementation of the modification impacts the plant specific inputs to the seal model.
Implementation Therefore, the difference between the variant and post-transition Therefore, post-transition plant in the PRA model with with respect to primary coolant pump seals is in the instrument and control logic associated with pump operation. The variant plant represents the existing plant (no associated modification). The post transition plant model includes the altemative modification). alternative capability to trip the pumps from the control room. The post-transition the post-transition plant is compliant with respect to the requirement to ensure primary coolant pumps can be tripped from the control room the requirement following a fire. Consequently Consequently there is no difference between the 'compliant' compliant and 'post- post transition transition' plant.
The The modification reduces the risk associated with the existing pump pump control circuits which which may preclude the ability to trip the pumps due due to fire affects. Logic associated with with the proposed modification is the only difference between the variant and post- post-transition transition plant with respect to the pump pump seal seal model.
model.
A A summary summary of of the the method method and and the the quantitative quantitative results that that are are used used in in the PRA PRA are not not required because the difference required because the difference in the seal model in the seal model is: is:
- in in the the plant plant specific specific element element of of the the model, model,
- related related to to aa modification modification to to improve improve plant plant capability, capability,
- and and NOTNOT related related to to the the probability probability that that the the seal seal will will fail fail on on loss loss ofof cooling cooling REFERENC
REFERENCES:
ES:
1.1. WCAP-1 6175-P-A (Formerly WCAP-16175-P-A (Formerly CE CE NPSD NPSD 1199 1199 P, P, Revision Revision 1), 1), Model Model for for Failure Failure of of RCP Seals Given Loss of RCP Seals Given Loss of Seal Cooling in Seal Cooling in CE CE NSSS NSSS Plants, Plants, March March 2007.2007.
2.
- 2. WCAP-1 5749-P, Guidance WCAP-15749-P, Guidance for for the the Implementat Implementation ion of of the the CEOG CEOG Model Model for for Failure Failure ofof RCP Seals Given Loss of Seal Cooling RCP Seals Given Loss of Seal Cooling (Task 2083), (Task 2083), Revision Revision 1,1, December December 2008. 2008.
Page Page 22 of of 18 18
NRC REQUEST NRC REQUEST PRA RAI01.f.01 PRA RAIO1.f.O1 The response The response to PRA RAI to PRA RAI 01.f 01.f in in the the letter letter dated December 2, dated December 2, 2013, 2013, ADAMS ADAMS Accession Accession No. ML 13336A 649 indicates that the circuit No. ML13336A649 indicates that the circuit analysis of analysis identified instrumentation of identified instrumentation for for dominant operator Iidominant" operator actions actions hashas been been completed completed and and will will be incorporated into be incorporated into the the transition fire transition fire PRA PRA riskrisk results, results, which which is is to to be be provided provided in in response response to PRA RAI to PRA RAI 30.30.
- a. Discuss what what is meant by Iidominant" dominant relative to RG AG 1.200's, 1.200s, I~n An Approach For Determining The Determining The Technical Technical Adequacy Of Of Probabilistic Probabilistic Risk Assessment Results Results For Risk-Informe Risk-Informed Activities, definition d Activities", definition of aa significant basic event and and whether these these non-dominant actions are assumed to be failed in the fire PRA.
non-11dominant"
- b. If not assumed to be failed, justify this treatment by discussing the risk significance non-dominant operator actions on the transition risk results.
of the credited non-dominant
RESPONSE
ENO RESPONSE Dominant operator actions in the context of the discussion provided in the original
- a. 'Dominant' response to 01.f 01 .f was related to a set of operator actions which would be required to be maintained as detailed human error probabilities (HEPs) to offset increases in core damage frequency (CDF) (ODE) resulting from the assignment of screening or scoping HEPs to other human failure events (HFEs). (HEEs). In addition, the discussion does not mean that other (non dominant) 'dominant') actions did not already have instrumentat instrumentation ion supporting the operator action included in the model. The discussion discussion was only meant to convey that some actions in the dominant set did not have instrumentat instrumentation ion available at that time.
- b. ItIt is not the case that all non non dominant
'dominant' operator actions are are assumed to be be failed in in the fire PRA.
PRA. The group of of non-domina non-'dominant' nt operator operator actions includes two subsets comprised comprised of of HFEs HFEs assigned either either scoping scoping or or screening values. HFEs HFEs assigned assigned aa screening value (1.0), (1.0), are are assumed failed in in the the fire PRA.
PRA. Events Events assigned assigned scoping scoping values values are are analyzed analyzed in in the the same same manner manner as the dominant as the 'dominant' HFEs HFEs to to the the extent extent that that instrumentat instrumentation ion isis included included in in the the model, model, fire induced induced impacts impacts areare considered; access access to to the the area area where where the the action action is is to be completed to be completed is is required, required, operator operator ability ability to to complete complete the the action action is is required required and and instrumentat instrumentation ion availability availability impacts impacts areare considered.
considered. Scoping Scoping HFEs HFEs without without supporting supporting instrumentat instrumentation ion included included in in the the model or those model or those for for which which thethe fire fire fails fails the the instrumentat instrumentation ion would would be failed in be failed in the the fire fire PRA.
PRA. Revised Revised risk risk results results reflecting reflecting thethe implementati implementation on ofof the the above above process process for for incorporation incorporation of of operator operator actions actions will will be be provided provided in in response response to to RAI RAI 30.
30.
Page Page 33 ofof 18 18
NRC REQUEST NRC REQUEST PRA RAI01.h.01 PRA RAI O1.h.O1 In the In the letter letter dated dated December December2, 2, 2013, 2013, ADAMS ADAMS Accession Accession No. No. MLML13336A649, 13336A649, the the response response to PRA RAI to PRA RAIO1.h, subsection 3) 01.h, subsection Justifications for
- 3) 'ljustifications forAssumptio Assumptions Identified as ns Identified as Non-Conseivative in Non-Conservative in the the licensee's licensees analysis" analysis describes describes that that the the treatment treatment of location in of location in the dependency the dependency analysis analysis differs differs fromfrom the the guidance guidance in in NUREG-1921, NUREG-1921, "EPRIINRC-RES EPRI/NRC-RES Fire Human Fire Human Reliability Reliability Analysis Analysis Guidelines, Guidelines, Draft Draft Report Report for for Comment".
Comment NUREG-1921 NUREG-1921 guidance does not guidance does not "negate the negate the possibility possibility of of success success of of all subsequent actions" all subsequent actions after after failure of failure of an action in an action in the main control the main control room room as as stated stated inin the the RAI RAI response response but but does does state that state that there there would would be be high high dependence dependence between between all all actions.
actions. Simply Simply stating stating that that the the approach is approach not realistic is not realistic is not sufficient is not sufficient justification justification to to deviate deviate from from the the NUREG.
NUREG. ItIt also also appears that appears that the the timing decision branch decision branch of of Figure 6-1 of of NUREG-1921 NUREG-1921 is is not utilized by the dependency the dependency analysis for for sequential actions due due to to this deviation.
Provide a time and distance justification for each set of control room actions considered Provide to be in different locations or conform to the accepted method. Identify the final approach used in the response to PRA RAI 30.
approach ENO RESPONSE ENO RESPONSE Palisades Nuclear Plant (PNP) will follow the NUREG-1921 Palisades NUREG-1 921 guidance and treat all actions actions taken in the control room as taking place within a single (same) location. The impact of these changes will be reflected in the quantificatio quantification n results documented in response response to PRA RAI 30.
NRC NRC REQUEST PRA PRA RAI O1.h.02 RAI01.h.02 The The dependency dependency analysis analysis described in in response to to PRA PRA RAI RAI 01.h 01.h does does notnot indicate that that aa minimum value was minimum value was utilized utilized forfor the the joint joint probability probability of of multiple multiple human human failure events events (HFE)
(HFE) and and thethe response. The The statement, statement, e.g.,"e.g., for zero zero dependence, dependence, the the conditional conditional human human errorerror probabilities probabilities (HEP) (HEP) is is equal equal to to the the independent independent HEP HEP" implies implies thatthatjoint joint HEPs HEPs may may take take on on any any value.
value. Section Section 6.2 6.2 of of NUREG NUREG 1921 1921 addresses addresses the the need need to to consider a minimum (floor) consider a minimum ("f1oor'? value for value for the the joint joint probability probability of of multiple multiple HFEs.
HFEs. Each Each value value less less than than the the floor floor value value should should be be individually individuallyjustified.
justified.
Considering Considering this this guidance, guidance, describe describe and andjustify thatjoint justify that joint HEP HEP values values that that appear appear in in fire fire PRA PRA cutsets cutsets including including any any values values less less than than thethe floor value. IfIfaa HEP floor value, HEP floor floor for for cutsets cutsets was was notnot used used consistent consistent with with NUREG-NUREG-1921 1921 (i.e.,
(i.e., 11E-5 E-5 with withjustifications justifications for for lower lower values),
values), provide provide updated updated risk risk results results as as part part of of the the aggregate aggregate change-in-ris change-in-risk analysis k analysis requested requested in in PRA PRA RAI RA130,30, which which isis consistent consistent with with NUREG-192 NUREG-1921 1 guidance.
guidance.
Page Page 44 of of 18 18
ENO RESPONSE ENO RESPONSE PNP will PNP will follow follow the the guidance guidance of of NUREG-1921 NUREG-1 921 and and utilize utilize aa floor floor value value ofof 11 E-5 E-5 for for all all conditional joint HE Ps. The impact of these conditional joint HEPs. The impact of these changes will changes will be be reflected reflected inin the the quantification results quantification results documented documented in in response response to PRA RAI to PRA RAI 30.30.
NRC REQUEST NRC REQUEST PRA RAI01.k.01 PRA RAIOLk.O1 The response to PRA RAI 01.k, in the letter dated December 2,2013, 2, 2013, ADAMS Accession No. ML13336A649, Accession 13336A649, indicates that main control room (MeR) (MCR) abandonment abandonment is only postulated for those fires resulting in a loss of MeR MCR habitability; however, the response to PRA RAI 03, in the letter mentioned above, states that lithe response the RAI Response Fire PRA Model will include additional scenarios that model MeR Fire MCR abandonment due to abandonment equipment equipment damage, with control being transferred to other locations, such as the alternate shutdown panel". panel If the the intent is to credit MeR abandonment due to loss of control, provide aa description MCR abandonment of the of the method and its technical justification. Include an explanation of the supporting analysis, work performed, and process followed in the technical justification.
ENO RESPONSE The response to PRA RAI 01 .k was intended to indicate that control room abandonmen 01.k abandonmentt due to loss of control or function is not explicitly explicitly modeled in the Fire PRA. That is, specific identification of those fire events events which lead lead to loss loss of control or function is not part of the fire scenario scenario development development and initial quantificatio quantification n process.
process. Only Only scenarios that that result in in control room abandonmen abandonmentt due due to loss of habitability habitability are are explicitly identified identified as as control room abandonmen abandonmentt scenarios.
scenarios.
- However, However, the the Fire Fire PRA PRA model model does does include include credit credit for for operator operator deployment deployment for local local actions actions (including (including local local actions actions atat the the alternate alternate shutdown panel) panel) as as potential potential success success paths paths in in the the accident accident sequence sequence development development.. Use Use of of these these alternate alternate success success pathspaths is is not limited not limited to to control control room abandonmen abandonmentt scenarios scenarios due due to to loss loss ofof habitability.
habitability.
The The response response to to PRA PRA RAI 03 for RAI 03 for FSS-B1-01 FSS-B1-01 was was intended intended to to indicate indicate that that additional additional control control roomroom scenarios scenarios are are being being added added to to the the RAI RAI Response Response Fire Fire PRA PRA model.
model. TheseThese additional additional scenarios scenarios alsoalso credit credit operator operator deployment deployment for for local local actions actions including including locallocal actions actions at at the the alternate alternate shutdown shutdown panel.
panel. TheThe intent intent isis not not to to explicitly explicitly identify identify and and credit credit control control roomroom abandonmen abandonment t due due toto loss loss ofof control.
control.
Page Page 55 of of 18 18
NRC REQUEST NRC REQUEST PRA RAI01.mm.01 PRA RAIO1.mm.O1 The response The response toto PRA PRA RAI RAI 01.mm, 01.mm, inin the letter dated the letter December 2, dated December 2, 2013, 2013, ADAMS ADAMS Accession No.
Accession No. ML ML13336A649, 13336A649, indicates indicates that that key key assumptions assumptions andand sources sources ofof uncertainty were identified. Provide uncertainty were identified. Provide aa table table that that describes describes these these key key assumptions assumptions and and sources of sources of uncertainty uncertainty that that assesses assesses their their impact impact onon the the NFPA NFPA 805805 application.
application.
ENO RESPONSE ENO RESPONSE In the In development of the development each Fire of each Fire PRA PRA report, report, aa section section was was included included that that identified identified assumptions related related to each each ofof the associated Fire Fire PRA PRA tasks included included inin that that specific specific notebook. For notebook. For each each of the identified assumptions, assumptions, a qualitative qualitative assessment assessment was documented regarding the potential quantitative impact as itit applies to the base fire documented PRA model which serves as part of the characterization characterization of the assumptions. In the PNP Quantification and Summary Notebook [1], these assumptions were reviewed Fire PRA Quantification to develop a table that identified sources of uncertainty by each NUREG/CR-6850NUREG/CR-6850 task and assessed the sensitivity of their impact on the NFPA 805 application. A modified and version of this table is provided below.
version below, It has been updated to account for the status of the RAI Response Fire PRA model and updated to specifically identify the potential key the assumptions associated with the sources of uncertainty.
assumptions Page Page 66 ofof 18 18
FPRA UNCERTAINTY FPRA UNCERTAINTY AND AND SENSITIVITY SENSITIVITY MATRIX MATRIX POTENTIAL KEY POTENTIAL KEY SENSITIVITY SENSITIVITY OF OF THETHE TASK TASK TASK TASK ASSUMPTIONS ASSUMPTIONS RESUL RESULTS TS TO TO THE THE TASK TITLE TASK TITLE NO.
NO. DESCRIPTION DESCRIPTION AND SOURCES AND SOURCES OF OF SOURCE(S)
SOURCE(S) OF OF UNCERTAINTY UNCERTAINTY UNCERTAINTY UNCERTAINTY 1 Plant The fire The fire PRA PRA analysis analysis This task This task posed posed aa limited limited During scenario During scenario development, development, Plant Boundary Boundary boundary was boundary was opportunity for opportunity for the the the the zone zone of of influence influence waswas not not D e ml ion and Definition an d determined, and and the plant the plant identification of determined, identification of potentially potentially limited to limited to the the physical physical analysis analysis Partitioning Partitioning was partitioned was partitioned into into key assumptions key assumptions and and related related unit boundary unit boundary for for most most discrete physical discrete physical analysis analysis sources of sources of uncertainty uncertainty compartment scenarios.
compartment scenarios. IfIf the the units (PAUs) units (PAUs) based based onon beyond the beyond credit taken the credit taken for for zone zone ofof influence influence included included the physical the physical the physical the physical presence presence of of targets in targets in adjacent adjacent fire fire characteristics of characteristics of the boundaries and boundaries and partitions.
partitions. areas/zones, these targets were were various areas.
various areas. also included, also included, regardless regardless of of their their fire area/zone location.
fire location. In In addition, a multi-compartment multi-compartment analysis further reduced analysis uncertainty by uncertainty by addressing the potential impact of of failure of partition elements on quantification.
quantification.
22 Fire PRA Fire PRA The fire PRA components This task posed perhaps the The potential for uncertainty was were selected by highest potential for error if reduced as a result of multiple C omponen Component reviewing the not uncertainty. The overlapping tasks including the over1apping Selection components in the FPIE mapping of basic events to MSO expert panel process PRA model and the components required not combined with reviews of equipment included in the only the consideration of screening initiating events, deterministic Nuclear Nuclear failure modes (active versus screened containment Safety Capability passive) but an penetrations, and screened Assessment (NSCA) understandin understanding g of the ISLOCA scenarios. Additional ISLOCA Additional analysis.
analYSis. The data were were Appendix RJNSCA R1NSCA functions internal reviews and the change analyzed with respect to not not previously considered evaluation process provided the their suitability suitability to to be be risk significant in in the FPIE opportunity to further reduce reduce included included in in the fire PRA model. uncertainty uncertainty in this this task.
model. Additional Additional consideration considerations, s, including including the potential potential effects effects of of Multiple Spurious Spurious Operations Operations (MSO5),
(MSOs), were were used used to to evaluate evaluate thethe need need to include additional to include additional corn ponents.
components.
Page Page 77 of of 18 18
FPRA UNCERTAINTY FPRA UNCERTAINTY AND AND SENSITIVITY SENSITIVITY MATRIX MATRIX POTENTIAL POTENTIAL KEY KEY SENSITIVITY SENSITIVITY OF OF THE THE TASK TASK TASK TASK ASSUMPTIONS ASSUMPTIONS RESULTS RESULTS TO TO THE THE TAS K TITLE TASK TI TIE NO.
NO. DESCRIPTION DESCRIPTION AND AND SOURCES SOURCES OF OF SOURCE(S)
SOURCE(S) OF OF UNCERTAINTY UNCERTAINTY UNCERTAINTY UNCERTAINTY 3 Fire Cable PRA Cable Cables were Cables were assigned assigned to to NoNo treatment treatment of of uncertainty uncertainty isis The The cable cable selection selection approach approach Fire PRA the components components based S e I ec IOfl the based typically required typically required for forthis this task task was was based based on on the the failure failure fault fault Selection on existing existing Fire Fire Safe Safe beyond the the understanding consequences consequences identified on beyond understanding of of identified for for each each Shutdown cable Shutdown cable the cable the cable selection selection approach approach cable cable relative relative to to the the operation operation of of evaluations and evaluations and for the for the various various iterations iterations of of the the associated associated component.
component.
additional cable additional cable cable identification cable identification tasks. tasks. These These faultfault consequences consequences were were identification.... Tasks identification Tasks 22 Additionally, PRA Additionally, PRA credited credited identified identified in in the the original original Appendix Appendix and 33 were and were performed performed components for components for which which cable cable RR data.
data. AA seperate seperate effort effort was was iteratively with iteratively with the the Plant Plant routing information routing information was was notnot performed performed to to review review this this data data in in Fire Induced Fire Induced Risk Risk Model Model provided (credit provided (credit by by exclusion) exclusion) light light ofof current current practices practices to to (Task 5).
(Task 5). represents aa potential represents potential key key assure assure its its fidelity.
fidelity. SinceSince assumption and assumption and source source of of Palisades Palisades has has undergone undergone an an uncertainty. Recognizing uncertainty. Recognizing extensive extensive effort effort to to identify identify cables cables that the that the potential potential exists exists to to for for components components beyond beyond those those improperly credit improperly credit these these addressed addressed in Appendix R, in Appendix R, components where components where theirtheir uncertainty uncertainty associated associated with with cables are cables are located located (non-(non- unknown unknown cable locations locations (UNL (UNL conservative), itit can be conservative), components) components) has has beenbeen greatly greatly assumed that these reduced. In In order to to eliminate eliminate components are failed excessive conservatism, conservatism, UNL UNL (conservative),
unnecessarily (conservative). components were credited credited by by exclusion - either explicitly explicitly oror based on assumed cable cable routing.
routing.
In any event, the assumed assumed cable cable routing is identified as as a potential a potential key source of of uncertainty.
4 Qualitative A small small number number of of plant Structures from the the global global No structure with credited No credited PRA PRA Qualitative areas SScreening creening areas met met all all of the analysis analysis boundary, boundary, and and components was excluded.
components excluded. This This criteria necessary necessary for ignition ignition sources sources deemed deemed to to exclusion criterion exclusion criterion is is not not subject subject qualitative qualitative screening.
screening. have have no no impact impact on on the the FPRA, FPRA, to uncertainty.
to uncertainty. In In the the event event that that were excluded were excluded from from the the aa structure structure whichwhich couldcould lead lead toto aa quantificatio quantification n based based on on plant trip plant trip was was excluded excluded qualitative qualitative screening screening criteria.
criteria. incorrectly, its incorrectly, its contribution contribution to to The only assumptions The only assumptions CDF would CDF would be be small small (with(with aa subject subject to to uncertainty uncertainty are are the the CCDP commensura CCDP commensurate with base te with base judgments judgments regardingregarding the the risk) and risk) and would would likelylikely be be more more potential potential for for plant plant trip trip used used than offset than offset by by inclusion inclusion of of the the as as part part of of thethe screening screening additional ignition additional ignition sources sources and and process.
process. the subsequent the subsequent reduction reduction of of other scenario other scenario frequencies.
frequencies. AA similar argument similar argument can can be be made made for ignition for ignition sources sources for for which which scenario refinement scenario refinement was was deemed deemed unnecessary.
unnecessary.
Page Page 88ofof 18 18
FPRA UNCERTAINTY FPRA UNCERTAINTY AND AND SENSITIVITY SENSITIVITY MATRIX MATRIX POTENTIAL KEY POTENTIAL KEY SENSITIVITY SENSITIVITY OF OF THE THE TASK TASK TASK TASK ASSUMPTIONS ASSUMPTIONS RESUL RESULTS TS TO TO THE THE TASK TITLE TASK TITLE NO.
NO. DESCRIPTION DESCRIPTION AND SOURCES AND SOURCES OF OF SOURCE(S)
SOURCE(S) OF OF UNCERTAINTY UNCERTAINTY UNCERTAINTY UNCERTAINTY 55 Plant Fire Plant Fire The PNP The PNP fire fire PRA PRA model model The construction The construction of of the the FPIE and FPIE and FPRA FPRA peer peer reviews reviews was developed was developed using using FPRA plant FPRA plant response response model model (including the (including the F&O F&0 resolution resolution Induced Risk Induced Risk applicable portions portions of of the the itself isis aa source source of applicable itself of process and process and thethe subsequent subsequent RAI RAI Model Model FPIE model.
FPIE model. The The model model uncertainty. The uncertainty. The same same resolution process),
resolution process), intemal internal was expanded was expanded as as sources of sources of assessments, and assessments, and the the change change necessary to necessary to include include uncertainty/sensitivity that uncertainty/sensitivity that evaluation process evaluation process are are useful useful in in additional sequences additional sequences are applicable are applicable to to the the base base exercising the exercising the model model andand associated with associated with fire fire model are model are applicable applicable to the to the identifying weaknesses. In identifying In events. Cables events. Cables werewere FPRA. However, FPRA. However, these these are are addition, the addition, FPRA model the FPRA model linked with linked with basic events basic events judged to to be minor in be minor in the the changes are changes are incorporated incorporated into into in the model and context of the context the overall Fire Fire the FPIE mode/.
the FPIE model. This assures assures associated to plant associated PRA model PRA model development development sequences are that these sequences are locations allowing locations process in process in the context of the context the of the exercised and reviewedreviewed evaluation of fire-induced NFPA 805 application. continually - not not just for fire PRAPRA circuit failures on a per applications.
scenario basis. Some 9,000+ failure modes (random and fire) are The potential for managing this included in the FPRA plant amount of data was addressed response mode/. model. This by employing different industry includes a highly detailed codes that were used to validate representation of potential the quantified results. By failures (e.g., down to the employing different codes, contact pair level) and fully problems with input are better developed common cause captured as each code provides failure modeling. Several different reports, different thousand cables are mapped diagnostic capabilities, etc.
to the associated basic events. The detailed modeling employed in the Palisades analyses The bookkeeping challenge ensures better rigor, insights, of managing this amount of and reduces errors, and and reduces and reduces data introduces potential data potential the epistemic uncertainty.
uncertainty.
error.
Moreover, such such detailed detailed modeling results results in in conservative numerical numerical results results as as failures areare double double counted; however,however, thisthis increases thethe aleatory aleatory uncertainty.
uncertainty. ItIt is is considered considered that that the importance the importance of of reducing reducing the the epistemic epistemic uncertainty uncertainty at at the the expense expense of of increasing increasing thethe aleatory aleatory uncertainty uncertainty greatly greatly benefits benefits the the development development of of additional risk insights.
additional risk insights.
Page Page 99 of of 18 18
FPRA UNCERTAINTY FPRA UNCERTAINTY AND AND SENSITIVITY SENSITIVITY MATRIX MATRIX POTENTIAL KEY POTENTIAL KEY SENSITIVITY SENSITIVITY OF OF THE THE TASK TASK TASK TASK ASSUMPTIONS ASSUMPTIONS RESUL RESULTS TS TO TO THE THE TASK TITLE TASK TITLE NO.
NO. DESCRIPTION DESCRIPTION AND SOURCES AND SOURCES OF OF SOURCE(S)
SOURCE(S) OF OF UNCERTAINTY UNCERTAINTY UNCERTAINTY UNCERTAINTY 66 Fire Ignition Fire Ignition A fire ignition A fire ignition frequency frequency The frequency The frequency values values from from A Bayesian A Bayesian updateupdate process process for for was estimated was estimated for for each each NUREG/CR-6850 and NUREG/CR-6850 EPRI and EPRI PNP events PNP events after after 2000 2000 was was Frequency Frequency plant compartment compartment based based Report 1016735 1016735 include include plant Report applied to applied to the the generic generic on fixed sources on fixed sources and and uncertainty to uncertainty account for to account for frequencies taken frequencies taken from from transient factors.
transient factors. The The variability among variability among plants plants NUREG/CR-6850 and NUREG/CR-6850 and thethe EPRI EPRI frequencies were frequencies were along with along with some some significant significant 1016735 data.
1016735 data.
ultimately applied ultimately applied on on aa conservatism in conservatism in defining defining thethe scenario basis.
scenario basis. The The frequencies, and and their their The applicablilty The applicabilIty of of the the ignition ignition approtionment of approtionment of the fire fire associated heat associated heat release release frequency data frequency data is identified identified as as aa frequency was was donedone inin rates, based rates, based on on limited potential key source potential source of of accordance with detailed data. uncertainty.
NUREG/CR-6850 NUREG/CR-6850 guidance and and associated associated potential key A potential key assumption is is FAQ5.
FAQs. that the that the fire ignition frequency data is applicable and provides an* an accepted estimate of the fire frequency for PNP.
7 Quantitative An initial quantification of Other than the conservative Quantitative screening was Quantitative the fire PRA model was treatment asscoiated with limited to refraining from further Screening performed to identify the retaining all scenarios, there scenario refinement of those relative risk contribution is no uncertainty from this scenarios with a resulting CDF /
of each physical analysis task on the FPRA results. LERF below the screening unit (PAU). No actual threshold. All of the results were screening was performed retained in the cumulative CDF /
as all PAUs were as all LERF.
retained in the quantification. This step was was usedused to to identify compartment compartments s where where detailed detailed analyses analyses would be appropriate.
be appropriate.
88 Scoping Scoping Scoping fire fire modeling modeling is is aa This This task task by by itself itself does does not Scoping Fire Fire not The The employment employment of of generic generic fire fire coarse coarse approach approach used used to to contribute contribute to to uncertainty, uncertainty. modeling modeling solutions solutions did did not not Modeling Modeling bound bound the the fire effects effects ofof However, However, the the approach approach taken taken introduce introduce any any significant significant certain certain ignition ignition sources.
sources. for for this task included:
this task included: 1) 1) conservatism conservatism.. DetailedDetailed fire fire AA more more refined refined approach, approach, generic generic firefire modeling modeling modeling modeling was was performed performed on on generic generic modeling, modeling, was was treatments treatments used used in in lieu lieu of of those those scenarios scenarios whichwhich otherwise otherwise employed employed at at PNP.
PNP. A A conservative conservative scoping scoping would would havehave been been notable notable risk risk detailed detailed analysis analysis was was analysis analysis techniques techniques and and 2)
- 2) contributorsa contributorsand applied where nd applied where performed performed for for typical typical limited limited detailed detailed fire fire modeling modeling the the reduction reduction in in conservatism conservatism ignition ignition sources sources based based on on performed performed to to refine refine the the was likely was to have likely to have aa measurable measurable their their physical physical properties properties scenarios scenarios developed developed using using impact.
impact.
and and prescribed prescribed heat heat the the generic generic fire fire modeling modeling release release rates.
rates. This This solutions.
solutions. The The primary primary The NUREG/CR The NUREG/CR-6850 -6850 heatheat analysis analYSis yielded yielded aa conservatism conservatism introduced introduced by by release rates introduce release rates introduce guideline guideline for for the the this this task task isis associated associated with with significant Significant conservatism conservatism given given evaluation evaluation of of fire fire damage damage the heat the heat release release rates rates the the limited limited fire fire test test data data available available effects effects for the various for the various specified specified inin NUREG/CR-NUREGlCR- to define to the heat define the heat release release rates rates ignition ignition sources.
sources. This This 6850.
6850. and and the the associated associated fire fire enabled enabled the the development development development development timeline.
timeline. However, However, of aa basic of basic scenario scenario for for alternative alternative treatments treatments are are not not many manysources sources that that could could currently currently accepted.
accepted.
be be treated treated as as bounding.
bounding.
Page Page 10 10 of of 18 18
FPRA UNCERTAINTY FPRA UNCERTAINTY AND AND SENSITIVITY SENSITIVITY MATRIX MATRIX POTENTIAL KEY POTENTIAL KEY SENSITIVITY SENSITIVITY OF OF THE THE TASK TASK TASK TASK ASSUMPTIONS ASSUMPTIONS RESUL RESULTS TS TO TO THE THE TASK TITLE TASK TITLE NO.
NO. DESCRIPTION DESCRIPTION AND SOURCES AND SOURCES OF OF SOURCE(S)
SOURCE(S) OF OF UNCERTAINTY UNCERTAINTY UNCERTAINTY UNCERTAINTY 9 Detailed Circuit Circuit failures Circuit failures were were Uncertainty considerations Uncertainty considerations Circuit analysis Circuit analysis waswas performed performed Detailed Circuit evaluated on evaluated on aa failure failure are limited to are limited to errors errors in in circuit circuit part of as part as of the Fire Safe the Fire Safe Failure Analysis Failure Analysis mode basis using the basis using the failure analysis analysis where mode failure where aa Shutdown // NSCA Shutdown NSCA analysis analysis and and data provided data provided in in the the cable was cable was deemed deemed incapable incapable supplemental circuit supplemental circuit selection selection original Appendix original Appendix R R of causing of causing lossloss of of aa particular particular efforts. Refinements efforts. Refinements in in the the analysis and analYSis and additional additional function credited function credited in the in the application of application the circuit of the circuit analysis analysis cable data cable data selection selection FPRA. Similar FPRA. Similar to to Task Task 22 results to results to the fire PRA the fire PRA were were efforts. In efforts. many cases In many cases (with the (with exception of the exception of the the performed on performed on aa case case byby case case additional circuit additional circuit reviews reviews MSO process),
MSO process), this task has has basis where the basis the scenario scenario risk risk necessary to were necessary no associated uncertainty no associated uncertainty ifif quantification was quantification was large large enough enough determine the determine the specific specific performed correctly.
performed to warrant further analysis.
failure consequences consequences of cables on cables individual on individual equipment.
10 Circuit Failure Circuit Circuit failures based off The uncertainty associated Circuit failure mode likelihood the failure mode were with the applied conditional analysis was generally limited to M 0 d e Likelihood Mode Li,e ih I 00 d evaluated in Task 9. In failure probabilities posed those components where Analysis Analysis some cases, additional considerations.
competing considerations. spurious operation could not be circuit failure likelihood On the one hand, a failure caused by the generation of a analysis was needed. If probability for spurious spurious signal. This approach applicable, failure operation could be applied limited the introduction of non-probabilities were applied based solely on cable scope conservative uncertainties.
uncertainties.
to specific cable failure without consideration of less Additional refinement to this modes. direct fire effects (e.g., a approach was performed on risk failure likelihood likelihood applied to significant scenarios.
scenarios. Given this the spurious operation of of an an treatment, the application application of MOV MOV without consideration of circuit circuit failure probabilities is is not not the fire-induced fire-induced generation generation of of considered considered to to be a potential keykey spurious spurious signal to to close close or or source source ofof uncertainty.
uncertainty.
open the MOV).MOV). On On thethe other other hand, hand, a failure probability probability forfor spurious spurious operation operation could be be applied applied despite despite the absence absence of of cables cables capable capable ofof causing causing spurious spurious operation operation in in that that location.
location.
Page Page 1111 of of 18 18
FPRA UNCERTAINTY FPRA UNCERTAINTY AND AND SENSITIVITY SENSITIVITY MATRIX MATRIX POTENTIAL KEY POTENTIAL KEY SENSITIVITY SENSITIVITY OF OF THE THE TASK TASK TASK TASK ASSUMPTIONS ASSUMPTIONS RESUL RESULTS TS TO TO THE THE TASK TITLE TASK TITLE NO.
NO. DESCRIPTION DESCRIPTION AND SOURCES AND SOURCES OF OF SOURCE(S)
SOURCE(S) OF OF UNCERTAINTY UNCERTAINTY UNCERTAINTY UNCERTAINTY Detailed Fire Detailed Fire 11 11 Modeling Modeling The application of The application of Utlimately, the Utlimately, the treatment treatment of of Detailed fire Detailed fire modeling modeling was was detailed fire detailed modeling fire modeling these issues these issues has has evolved evolved performed only performed only onon those those was limited was limited to to the the Main Main through the through the various various RAlsRAIs and and scenarios which scenarios which otherwise otherwise would would Control Room Control Room (MCR) (MCR) subsequent model subsequent model have been have notable risk been notable risk abandonment scenario, abandonment scenario, refinements to refinements reduce the to reduce the contributors and contributors and only only where where and aa few risk and risk significant significant number of number potential key of potential key removal of removal of conservatism conservatism in in the the areas (e.g.,
areas (e.g., inin the the 1C1 C and and assumptions.
assumptions. generic fire generic fire modeling modeling solution solution 11 D swithcgear rooms).
D swithcgear rooms). likely to was likely was provide benefit to provide benefit The majority The majority of of the other The analysis The analysis methodology methodology either via aa smaller smaller zone zone of scenarios were scenarios were analyzed analyzed conservatism is primarily is primarily influence or or toto credit credit automatic automatic using the using the generic fire associated with conservatism associated conservatism suppression.
suppression.
modeling treatments.
modeling treatments, in the heat in heat release rates rates specified in in NUREGlCR-NUREG/CR- Additional refinement of the fire This task alsoalso includes includes 6850.
6850. scenarios was pursued pursued using using the devleopment of a multi-point analysis of the heat multi-compartment multi-compartment The primary potential key release rates as opposed to the analysis and structural assumption and related use of a bounding fire for most steel analysis. source of uncertainty in this scenarios. Additional fire task is in the area of the time modeling was pursued in areas delay associated with cable of high risk, notably the damage that resulted in switchgear rooms.
several different related RAIs.
RAls. The time delay associated with cable damage that was incorporated into the fire modeling is identified as a potential key source of uncertainty.
Post-Fire Human 12 12 Reliability Reliability The post-fire HRA HRA was was Human Human error probabilities Detailed fire HEP HEP values have have Analysis (HRA) performed performed by by developing developing represent a potentially large not not been developed in in all cases, cases, a post-fire post-fire human human error uncertainty uncertainty for the FPRA and and screening or scoping seoping HEP HEP probability (HEP)
(HEP) for each each given the importance given the importance of values values have have beenbeen applied applied to to credited credited action.
action. For For human human actions actions in in the the base base some some of of the the less less risk risk significant significant cases cases where where detailed detailed model.
model. A A potential potential key key HEPs.
HEPs. This This approach approach shouldshould post-fire post-fire HEPs HEPs were were notnot assumption assumption is that the is that the HRA HRA help help reduce reduce the the impacts impacts of of developed, developed, screening screening or or methods methods utilized utilized forfor PNP PNP uncertainty uncertainty associated associated with with this this scoping scoping values values were were provide provide representativ representative e HEP HEP issue.
issue.
used used consistent consistent with with the the values values in in the the analysis analysis guidance guidance provided provided in in commensura commensurate with their te with their In any event, In any event, thethe human human error error NUREG-1 NUREG-1921. 921. importance.
importance. probabilities probabilities usedused in in the the Fire Fire PRA PRA model model are are identifed identifed asas aa potential potential key key source source of of uncertainty.
uncertainty.
Seismic Seismic Fire Fire 13 13 Interactions Interactions AA qualitative qualitative seismic-fire seismic-fire Since Since this this isis aa qualitative qualitative Seismic-fire Seismic-fire interaction interaction has has nono review review waswas performed performed evaluation, evaluation, therethere is is no no impact impact onon fire fire risk risk quantification.
quantification.
and documented.
and documented. quantitative quantitative impact impact withwith respect respect to to the the uncertainty uncertainty of of this this task.
task.
Page Page 12 12 of of 1818
FPRA UNCERTAINTY FPRA UNCERTAINTY AND AND SENSITIVITY SENSITIVITY MATRIX MATRIX POTENTIAL KEY POTENTIAL KEY SENSITIVITY SENSITIVITY OF OF THE THE TASK TASK TASK TASK ASSUMPTIONS ASSUMPTIONS RESULTS RESULTS TO TO THE THE TASK TITLE TASK T IT LE NO.
NO. DESCRIPTION DESCRIPTION AND SOURCES AND SOURCES OF OF SOURCE(S)
SOURCE(S) OF OF UNCERTAINTY UNCERTAINTY UNCERTAINTY UNCERTAINTY Fire Risk Fire Risk 14 14 Quantification Quantification The fire The fire PRA PRA was was As the culmination As the culmination of of other other Since the Since the fire fire PRA PRA solves solves for for quantified using quantified using the the tasks, most tasks, most of of the uncertainty the uncertainty CCDP (prior CCDP (prior to the application to the application of of FRANC analysis FRANC analysis tool.
tool. associated with associated with quantification quantification frequency) at frequency) at aa truncation truncation limit limit of of The quantitative The quantitative results results has already been has already been addressed.
addressed. 1 .OE-09 for 1.0E-09 for CDF CDF and and 1.0E-1 1 .OE-1O0 for for are summarized are summarized in in the the One source One source of of uncertainty uncertainty isis LERF, there LERF, there should should not not be be aa Fire PRA Fire PRA Quantification Quantification the selection of the selection of the the truncation truncation significant truncation significant truncation and Summary and Summary Notebook.
Notebook. limit, limit. contribution. These contribution. These truncation truncation limits are limits are several several orders of of magnitude below magnitude below the the typical typical values calculated.
values calculated. Additionally, Additionally, the final truncation the final truncation valuesvalues utilized the integrated in the integrated one-top model are compared to are to the the PRA PRA standard requirement of less than 5% change per decade of truncation and further discussed in the Fire PRA Quantification and Summary Notebook. As such, the truncation values utilized are not identified as a potential key source of uncertainty.
Uncertainty and 15 15 Sensitivity Sensitivity Uncertainty and This task does not introduce N/A Analysis Analysis Sensitivity are discussed any new uncertainties but is in the Fire PRA intended to address how Quantification and uncertainties may impact the Summary Notebook.
Notebook, fire risk.
Fire PRA PRA 16 16 Documentati Documentation on The The FPRA is is documented documented This This task does does not not introduce introduce The documentation documentation task task in in a series of reports. any new any new uncertainties to the the compiles the the results of of the other other fire risk. Uncertainty Uncertainty tasks. See See specific specific technical technical considerations should should be be tasks above tasks above for a discussion discussion of of documented documented in in aa manner manner that their their associated associated uncertainty and and facilitates facilitates FPRA FPRA applications, applications, sensitivity.
sensitiVity.
upgrades, upgrades, andand peer peer review.
review.
Based Based on on the the uncertainty uncertainty and and sensitivity sensitivity review summarized summarized above, above, potential potential key "key" assumptions (i.e.,(Le., those those that that could impact impact the the NFPA NFPA 805 805 application) application) were identified identified to to include:
include: non-suppress non-suppression ion probabilities associatedassociated with with thethe cable cable damage damage time, time, human human error error probabilities probabilities,, fire fire ignition ignition binbin frequencies frequencies (in (in addition addition to to the the sensitivity sensitivity analysis analysis required required by by the use of the use of NUREG/CR NUREG/CR-6850 -6850 Supplement Supplement 11 (EPRI) (EPRI) ignition ignition frequencies frequencies for for all bins), and assumed cable all bins), and assumed cable routings. routings.
Sensitivity Sensitivity analysis analysis are are performed performed for for each each of the potential of the potential key key sources sources of of uncertainty uncertainty identified identified above, above, and and these these sensitivity sensitivity casescases will will be be re-performed re-performed with with the the base base PAl RAI Response Fire PRA Model. The results Response Fire PRA Model. The results of these sensitivity of these sensitivity cases cases willwill be be included included in in the the updated updated revision to the revision to the Fire Fire PRA PRA Fire Fire Risk Risk Quantificatio Quantification n andand Summary Summary Notebook Notebook for for the RAI the RAI Response Response Fire Fire PRA PRA Model.
Model.
Page Page 13 13 of of 18 18
REFERENCES:
REFERENCES:
1.1. Palisades Palisades Nuclear Nuclear Plant Plant Fire Fire Probabilistic Probabilistic RiskRisk Assessment Assessment Fire Fire Risk Risk Quantification Quantification and Summary, and Summary, ERIN ERIN Report Report 0247-07-0005.01, 0247-07-0005.01, Revision Revision 1, 1, November November 2012. 2012.
NRC REQUEST NRC REQUEST PRA RAI PRA RAIO1.q.O1 01.q.01 The response The response to to PRA PRA RAIRAI 01.q, 01.q, inin the the letter letter dated December 2, dated December 2, 2013, 2013, ADAMS ADAMS Accession No. ML 13336A649, Accession No. ML13336A649, states that the states that the "time time delay delay method" method will will replace replace the the damage accrual "damage accrual method" method originally originally employed employed by by the the fire fire PRA.
PRA. NoteNote that that in in Section Section H. 1.5.2 of H.1.S.2 of NUREGICR-68S0, NUREG/CR-6850, the the failure failure times times reported reported in in Table Table H-8H-8 assume assume steady-steady-state fire exposure conditions and state fire exposure conditions and are therefore, therefore, not not applicable for for use use in calculating calculating exposure conditions exposure conditions that that evolve evolve over over time. Provide a technical time. Provide technical justification for for how thethe Wme delay method "time delay method" accounts accounts for pre-heating of targets targets that occurs at heat heat fluxes fluxes prior to reaching to reaching the the peak peak heat flux for the fire being analyzed including those below the target damage target damage threshold, and those not already taken into account by Table H-8.
Provide updated Provide updated risk results as part of the aggregate change-in-risk change-in-risk analysis requested in PRA RAI in PRA RAI 30 30 that appropriately account for pre-heating or that conservatively conseivatively do not credit the credit the time time delay delay associated with the pre-heating period.
ENO RESPONSE ENO RESPONSE Consistent Consistent with industry precedent (References 1, 1, 2), PNP will revise the Fire PRA RAI
Response
Response Model Model to use the damage
'damage accrual accrual' method using elements of of the Arrhenius methodology methodology (Reference (Reference 3, 4). As such, 3,4). such, technical justification justification of of the time
'time delay delay' method is not method is not provided.
provided. The The updated updated risk results will will be be included included in in the response to to RAI RAI 30.
30.
Due Due to to the the revised revised approach approach of of using using the the damage
'damage accrual accrual' method, method, reference reference to to the the time
'time delay delay' method method in in the the previously previously submitted submitted responses responses for for RAI RAI FMFM 0101.p and RAI
.p and RAI FM FM 02.b is superseded.
02.b is superseded.
REFERENC
REFERENCES:
ES:
1.
- 2. Turkey Turkey PointPoint - NFPA NFPA 805 805 LAR LAR RAls RAls 5-27-14 5-27-14 ML14132A0 ML14132A081 81 3.
- 3. User User Need Need Request Request on on the the Acceptability Acceptability of of the the Arrhenius Arrhenius Methodology Methodology for for Environment al Qualification Environmental Qualification (EQ) (EQ) for for LOCA LOCA and and POST-LOCA POST-LOCA Environment Environments, s, ML00370198 ML003701987, 7, February February 24, 24, 2000 2000 Page Page 14 14of of 18 18
- 4. PLP-RPT-00057, Attachment
- 4. PLP-RPT-00057, Attachment PRA-RAI-01.q.01 PRA-RAI-Ol .q.01 NRC REQUEST NRC REQUEST PRA RAI01.r.01 PRA RAI O1.r.O1 The response The response to to PRA PRA RAIRAI 01 Olr, in the r, in the letter letter dated December 2, dated December 2, 2013, 2013, ADAMS ADAMS Accession Accession No. ML No. ML13336A649, states that a one-minute time 13336A649, states that a one-minute time delay delay will will be be applied applied forfor credited credited automatic detection automatic detection systems.
systems.
- a. How
- a. How is is the the probability probability ofof failure failure of automatic detection of automatic detection included included in in the the PRA?
PRA?
- b. If
- b. If the the automatic automatic detection detection fails, fails, is manual manual detection detection thenthen credited?
credited?
When manual
- c. When manual detection is credited credited after automatic detection fails, is the 15 15 minute delay used?
delay used?
- d. If
- d. logical scenario of detection failure, manual detection with 15 minute delay, and If a logical attempted attempted manual suppression is not included in the PRA. Evaluate the impact on the results the results ofof not including this scenario or add it to the PRA.
- a. The fire PRA model is being updated to include the failure probability of automatic a.
detection systems credited in the calculation of manual non-suppression detection non-suppression probabilities (NSPs). As stated in the response to PRA RAI 01 01.r,
.r, no automatic detection systems were credited in support of the activation of automatic suppression systems as the automatic suppression systems are all wet-pipe systems. In In order to account for the failure probability of automatic detection detection systems credited in support of manual suppression, two sets of manual non- non-suppression suppression probabilities are being calculated for each each applicable applicable set set of of fire scenarios.;
scenarios. ;
1)
- 1) The The first first set set is is calculated assuming assuming the the automatic automatic detection detection system system fails fails and and the correspondin the corresponding g manual manual detection detection time time isis used used (e.g.
(e.g. 1515 minutes).
minutes).
2)
- 2) The The second second set is calculated set is calculated assuming assuming the the automatic automatic detection detection is is successful successful and and the the correspondin corresponding g time time toto detection detection is is used used (e.g.
(e.g. 11 minute).
minute).
These These two two sets sets of of NSPs NSPs areare pro-rated pro-rated by by the the automatic automatic detection detection system system success/failu success/failure re rates.
rates. The The first first set set of of NSPs NSPs areare multiplied multiplied by by the the automatic automatic detection detection system system failure failure probability probability (e.g.
(e.g. 0.05) 0.05) and and the the second second set set of of NSPs NSPs are are multiplied multiplied byby the the complement complement of of the the failure failure probability probability (e.g.
(e.g. 0.95).
0.95). TheThe pro-rated pro-rated NSPs NSPs from from each each set set areare summed summed and and applied applied to to the the appropriate appropriate fire fire scenarios.
scenarios.
Page Page 15 15 of of 18 18
- b. Yes,
- b. Yes, manual manual detection detection isis credited credited ifif automatic automatic detection detection fails fails as as discussed discussed inin the the response response to partto part a) above.
a) above.
- c. Yes,
- c. Yes, as discussed in as discussed in the the response response to to PRA PRA RAI RAI 01.r, 01 .r, the the application application of of aa 15 15 minute minute manual detection manual detection timetime isis applied applied whenwhen appropriate.
appropriate, IfIf manual manual detection detection isis notnot considered credible, considered credible, manual manual suppression suppression will will not not be be credited credited when when thethe automatic automatic detection system detection system isis assumed assumed to fail or to fail or isis nonexistent.
nonexistent.
- d. As
- d. discussed in As discussed in the the response response to to part part a) a) above, above, thethe fire fire PRA PRA model model isis being being updated updated so that so that the the NSPs NSPs applied applied to to fire fire scenarios scenarios crediting crediting automatic automatic detection detection also take also take into account into account the failure probabilities the failure probabilities of of these these automatic automatic detection detection systems, systems, and and the the resulting impact resulting impact on on thethe detection detection times.
times. An evaluation evaluation of of the the impact impact of not including of not including these scenarios these scenarios is is therefore therefore not not required.
required.
NRC REQUEST NRC REQUEST PRA RAJ PRA O1.yOl RAI 01.y.01 The response to PRA RAI 01.y, The O1.y, in the letter dated December 2, 2013, ADAMS Accession No. ML13336A649,13336A 649, appears to indicate that the barrier failure probability is defined by '1he defined the most limiting barrier (e.g., non-rated barrier, door, damper, or wall)" wall) and not the sum of the types of barriers present.
Demonstrate that the impact on the results is not significant or provide updated risk Demonstrate results as part of the aggregate change-in-ris change-in-risk k analysis requested in PRA RAI 30, summing summing the barrier failure probabilities for each type of barrier present per NUREG/CR NUREG/CR-6850. -6850.
ENO ENO RESPONSE
RESPONSE
In In response to this RAI, the multi-compa multi-compartment rtment barrier failure probability is being being updated updated to to sum the barrier sum the barrier failure probabilities probabilities for for each each type type ofof barrier barrier present present per per NUREG/CR NUREG/CR-6850. -6850. The risk risk results provided provided with with the the response to PRA PRA RAIRAI 30 30 will will reflect reflect this this change.
change.
NRC NRC REQUEST REQUEST PRA PRA RAI RAJ 12.01 12.01 The The ASME ASME PRA PRA standard standard calls for aa focused calls for focused scopescope peer peer review review for for PRA PRA upgrades, upgrades, where PRA upgrade is where PRA upgrade is defined in thedefined in the standard standard as: as:
The
'The incorporation incorporation into into aa PRA PRA model model of ofaa new new methodology methodology or orsignificant significant changes changes in scope or capability that impacts in scope or capability that impacts the significant the significant accident accident sequences sequences or or the the significant significant accident accidentprogression progression sequences.
sequences. "
Page Page 16 16 of of 18 18
The response The response to RAI 12 to RAI 12 states, states, "the the detailed detailed HEP HEP methodology methodology was was reviewed reviewedby by the the peer review peer review and and has has not not been been changed.
changed. As As such, such, aa focused focused scope scope review review of of the the HEP HEP analysis isis also analysis also not warranted. The not warranted." The response response to RA123.e states, to RA123.e states, 'Yhe use of the use ofNUREG-NUREG 1921 methods for screening, 1921 methods for screening, scoping scoping and and detailed detailed HEP HEP values values constitutes constitutes data data and and methods not methods not included included in in the the fire fire PRA PRA peer peer review.
review. However, However, these these data data and methods and methods are considered are considered acceptable acceptable for for use.
use."
a.a. Clarify Clarify these these conflicting conflicting statements statements considering considering thatthat using using data data and and methods methods acceptable for acceptable for use use isis unrelated unrelated to to the the need need for for aa peer peer review.
review.
- b. Describe the
- b. Describe the method method thatthat will will be be used used toto ensure ensure thatthat any any PRA PRA upgrade upgrade will will be be peer peer reviewed.
reviewed.
- a. The
the detailed HEP
the HEP methodology was reviewed by the peer review and has not been changed. As such, a focused scope review of the detailed HEP been methodology is also not warranted."
methodology warranted.
The response The response to PRA RAI 23.e should be clarified as:
the use
the use of NUREG-1921 NUREG-1921 methods for scoping HEP values constitutes a method not included in the fire PRA peer review. Therefore, the new method methods are considered to require a focused scope peer review."
methods review.
A A focused focused scope scope peer review on the use of NUREG-192 NUREG-1921 1 scoping methods will be performed consistent performed consistent with ASME/ANS ASMEIANS RA-Sa-2009 RA-Sa-2009.. Any findings and their resolution will will be be described described in in the response to PRA PRA RAI RA130.30.
b.
- b. ENOEND PRAPRA configuration configuration control procedure EN-DC-151 EN-OC-151 ensures ensures that that any PRA PRA upgrades upgrades receive appropriate appropriate peer peer reviews.
REFERENC
REFERENCES:
ES:
1.
- 1. NUREG-1 NUREG-1921, 921, Fire "Fire Human Human Reliability Reliability Analysis Analysis Guidelines, Guidelines", Final Final Report, Report, EPRI EPRI 1023001, 1023001, EPRI/NRC-R EPRI/NRC-RES, ES, July2012.
July 2012.
2.
- 2. ASME/ANS ASME/ANS RA-Sa200 RA-Sa-2009, 9, Standard "Standard for for Level 1/Large Early Level1/Large Early Release Release Frequency Frequency Probabilistic Probabilistic RiskRisk Assessment Assessment for for Nuclear Nuclear Power Power PlantPlant Applications Applications", ASME/ANS
, ASME/ANS RA-S RA-S Committee Committee and and ASME, ASME, February February 2009.2009.
3.
- 3. EN-DC-151, EN-OC-151, Revision Revision 5, 5, PSA "PSA Maintenance Maintenance and and Update, Update", Nuclear Nuclear Management Management Manual, Manual, November November 2013. 2013.
Page Page 1717 of of 18 18
NRC REQUEST NRC REQUEST PRA RAI31 PRA RAI31 The responses The responses toto several several PRA PRA RAls RAIs (e.g.,
(e.g., 01.g, 01.g, 01.cc, 01.cc, and and 03)
- 03) are contingent on are contingent on the the development of development ofaa new new '~II-inclusive" all-inclusive fire fire response response procedure.
procedure. Describe Describe ifif there is an there is an Implementation Item Implementation Item in in table table 5-3 S-3 that that addresses addresses thethe development development and and implementation implementation of this procedure.
of this procedure. IfIf not, not, describe describe thethe method method that that will will be be used used to to ensure ensure development development of of the procedure.
the procedure.
ENO RESPONSE ENO RESPONSE The completion The completion of of aa new new 'all-inclusive' all-inclusive procedure procedure is is an an implementation implementation action.
action.
Implementat ion item Implementation item 1, in 1, in Table S-3 5-3 ofof the PNP NFPA PNP NFPA 805 805 LAR, LAR, Attachment 5, S, addresses the development and addresses and implementation implementation of the new new "all-inclusive" all-inclusive fire response response procedure. Completion procedure. Completion of this implementation implementation itemitem isis controlled via the PNP PNP Commitment Tracking Process, specifically under LO-LAR-2013-00052.
Commitment LO-LAR-201 3-00052.
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