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{{Adams
#REDIRECT [[CP-201101565, Response to Request for Additional Information, Risk Informed Justification for the Relocation of Specific Surveillance Frequency Requirements to Licensee Controlled Program - Tacs ME6789 and ME6790]]
| number = ML11321A221
| issue date = 11/09/2011
| title = Response to Request for Additional Information, Risk Informed Justification for the Relocation of Specific Surveillance Frequency Requirements to Licensee Controlled Program - Tacs ME6789 and ME6790
| author name = Madden F W
| author affiliation = Luminant Generation Co, LLC, Luminant Power
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000445, 05000446
| license number =
| contact person =
| case reference number = CP-201101565, TAC ME6789, TAC ME6790, TXX-11136
| document type = Letter
| page count = 4
| project = TAC:ME6789, TAC:ME6790
| stage = Response to RAI
}}
 
=Text=
{{#Wiki_filter:a Luminant Rafael Flores Senior Vice President& Chief Nuclear Officer Rafael.Flores@Luminant.com Luminant Power P 0 Box 1002 6322 North FM 56 Glen Rose, TX 76043 T 254 897 5550 C 817 559 0403 F 254 897 6652 CP-201101565 Log # TXX-11136 Ref. # 10CFR50.90 November 9, 2011 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
 
==SUBJECT:==
COMANCHE PEAK NUCLEAR POWER PLANT (CPNPP)DOCKET NOS. 50-445 AND 50-446 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION, RISK INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO LICENSEE CONTROLLED PROGRAM -TACS ME6789 AND ME6790
 
==REFERENCES:==
: 1. Letter logged TXX-11093 dated August 1, 2011 from Rafael Flores to the NRC submitting License Amendment Request (LAR) 11-001, Application For Technical Specification Change Regarding Risk-Informed Justification For The Relocation Of Specific Surveillance Frequency Requirements To A Licensee Controlled Program.2. Letter logged TXX-11100 dated August 15, 2011 from Rafael Flores to the NRC submitting Supplement To License Amendment Request (LAR) 11-001, "Application For Technical Specification Change Regarding Risk-Informed Justification For The Relocation Of Specific Surveillance Frequency Requirements To A Licensee Controlled Program".3. Email dated October 26, 2011 from Balwant Singal of the NRC to Timothy Hope of Luminant Power requesting additional information regarding License Amendment Request (LAR) 11-001.
 
==Dear Sir or Madam:==
Per references 1 and 2, Luminant Generation Company LLC (Luminant Power) previously submitted License Amendment Request (LAR) 11-001 requesting changes to the Comanche Peak Nuclear Power Plant (CPNPP) Technical Specifications (TSs) for adoption of the Nuclear Regulatory Commission (NRC) approved Technical Specification Task Force (TSTF) -425, Revision 3, "Relocate Surveillance Frequencies to Licensee Control -RITSTF [Risk-Informed TSTF] Initiative 5b." Per reference 3, the NRC provided a request for additional information regarding the subject license amendment request.Luminant Power has provided the information requested per reference 3 in the Attachment to this letter.This communication contains no new commitments regarding Comanche Peak Units 1 and 2.Should you have any questions, please contact Mr. Rob Slough at (254) 897-5727.A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
* Comanche Peak
* Diablo Canyon -Palo Verde
* San Onofre
* South Texas Project -Wolf Creek U. S. Nuclear Regulatory Commission TXX-11136 Page 2 of 2 Sincerely, Luminant Generation Company LLC Rafael Flores By: K Mirer WMaddeh Director, Oversight
& Regulatory Affairs RAS
 
==Attachment:==
 
Response To Request For Additional Information
-Risk Informed Justification For The Relocation Of Specific Surveillance Frequency Requirements To Licensee Controlled Program -TACs ME6789 and ME6790 c -E. E. Collins, Region IV B. K. Singal, NRR Resident Inspectors, Comanche Peak Ms. Alice Rogers Environmental
& Consumer Safety Section Texas Department of State Health Services 1100 West 49th Street Austin, Texas 78756-3189 Attachment to TXX-11136 Page 1 of 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION
-RISK INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO LICENSEE CONTROLLED PROGRAM -TACS ME6789 AND ME6790 The following questions were provided to Luminant Power in the email dated October 26, 2011 from Balwant Singal of the NRC to Timothy Hope of Luminant Power (Reference
: 3) requesting additional information regarding LAR 11-001: 1. The summary of finding and observation (F&O) 2-13 for supporting requirement (SR) AS-A7 identifies that the documentation of assumptions and key sources of uncertainty for accident sequence modeling is incomplete, and two examples are provided by the peer reviewer.
The disposition of this F&O was to specifically address these two examples, but there is no discussion of any review to identify other sources of uncertainty not documented.
Since the peer review identifies the two specific items as examples, the U. S. Nuclear Regulatory Commission's (NRC)staff would not expect the licensee to close out this F&O until a more thorough review was conducted to assure all sources of uncertainty and assumptions are identified and discussed in the documentation.
Please discuss how this F&O was reviewed to determine the extent of condition for missing assumptions and key sources of uncertainty related to accident sequence modeling.2. The summary of F&O 4-31 for SR QU-F4 states that the effect of sources of uncertainty on the Probabilistic Risk Assessment (PRA) model is not clear. The resolution states that the documentation identifies the application of an industry guidance document to the evaluation of uncertainties.
This does not seem to address the underlying issue that the documentation should characterize sources of uncertainty and assumptions underlying the PRA model.Please clarify how this F&O was addressed to assure characterization of sources of uncertainty and assumptions on the effects on the PRA model is described in the documentation.
Luminant Power's Response to Question 1: F&O 2-13 included two proposed resolutions from the Peer Review team. The first proposed resolution dealt with the possible uncertainty from not including further development of offsite power recovery sequences.
The second proposed resolution dealt with potential uncertainties resulting from deviations in the incorporation of the WCAP-15831 ATWS model. The LAR submittal described the incorporation of these proposed resolutions into the CPNPP PRA model and/or model documentation.
Both of these items were added to the list of potential uncertainties in the respective PRA notebooks.
The proposed resolutions were limited to the two specific examples, and the performance of the uncertainty analysis (see RAI response #2) did not identify any additional sources of uncertainty that would impact Accident Sequence development.
Luminant Power's Response to Question 2: The proposed resolution to this F&O by the peer team was the following:
Consider using the approach recommended in the EPRI report 1016737, "Treatment of Parameter and Model Uncertainty for Probabilistic Risk Assessments," December 2008.The EPRI document identifies all sources of model uncertainty that are pertinent to a general PRA model in meeting the SRs: QU-E1, QU-E2, QU-E4, QU-F4, and LE-F3. Table A-1 from that document generically characterizes these sources. Per the peer review suggestion, the CPNPP PRA "Sensitivity and Uncertainty" notebook was updated to include this table (A-1) with the 4 Attachment to TXX-11136 Page 2 of 2 identification of the plant-specific approach used for each case and where each source of uncertainty can impact the model. The notebook (with its Level 2 reference) documents over 50 sensitivity cases performed on the model involving the full range of the uncertainties identified in the table. The revised "Sensitivity and Uncertainty" notebook documents the characterization of the sources of uncertainty and assumptions underlying the PRA model and resolves the Peer Review F&O.}}

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