CP-201200097, Response to Request for Additional Information for Relief Request No. A-1

Response to Request for Additional Information for Relief Request No. A-1

ML12060A348
Person / Time
Site:	Comanche Peak
Issue date:	02/21/2012
From:	Madden F Luminant Power, Luminant Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201200097, TAC ME6827, TXX-12014
Download: ML12060A348 (4)

Text

Rafael Flores Luminant Power Senior Vice President P 0 Box 1002

& Chief Nuclear Officer 6322 North FM 56 Glen Rose, TX 76043 a

Lu itRafael.Flores@Luminant.com Luminant 2548975550 C 817 559 0403 F 254 897 6652 CP-201200097 Ref. # 10CFR50.55a Log # TXX-12014 February 21, 2012 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK NUCLEAR POWER PLANT DOCKET NO. 50-445 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR RELIEF REQUEST NO. A-1 (TAC NO. ME6827)

REFERENCES:

1. Letter logged TXX-11038 dated August 2, 2011 from Rafael Flores to the NRC submitting Relief Request No. A-1 for the Unit 1 Third Interval Inservice Inspection for Application of an Alternative to the ASME Boiler and Pressure Vessel Code Section XI Examination Requirements for Class I and 2 Piping Welds (Third Interval Start Date: August 13, 2010).

2. Email dated January 25, 2012 from Balwant Singal of the NRC to Timothy Hope of Luminant Power requesting additional information regarding Relief Request No. A TAC ME6827.

Dear Sir or Madam:

Per reference 1, Luminant Generation Company LLC (Luminant Power) previously submitted a request for relief for application of an alternative to the American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code Section XI examination requirements for Class 1 and 2 piping welds.

Per reference 2, the NRC provided a request for additional information regarding the subject relief request.

Luminant Power has provided the information requested per reference 2 in the attachment to this letter.

This communication contains no new commitment regarding Comanche Peak Unit 1.

Should you have any questions, please contact Mr. Jack Hicks at (254) 897-6725.

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-12014 Page 2 of 2 Sincerely, Luminant Generation Company LLC Rafael Flores By: &A7,.*.L, Director, Oversight & Regulatory Affairs Attachment Response to Request for Additional Information for Relief Request A-1 c- E. E. Collins, Region IV Luis Ponce B. K. Singal, NRR Environmental & Consumer Safety Section Resident Inspectors, Comanche Peak Texas Department of State Health Services Jack Ballard, ANII, Comanche Peak 1100 West 49th Street Austin, Texas 78756-3189

Attachment to TXX-12014 Page 1 of 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR RELIEF REQUEST NUMBER A-1 FOR THE UNIT 1 THIRD 10 YEAR ISI INTERVAL (THIRD INTERVAL START DATE: AUGUST 13, 2010) (TAC NO. ME6827)

The following questions were provided to Luminant Power in the email dated January 25, 2012, from Balwant Singal of the NRC to Timothy Hope of Luminant Power (reference 2) requesting additional information regarding Relief Request Nos. A-i:

NRC Question 1:

The Luminant Generation Company LLC (Luminant, the licensee) used Electric Power Research Institute (EPRI) Topical Report (TR) 1018427 to address those supporting requirements significant to the PRA for risk-informed inservice inspections (RI-ISI). The NRC has endorsed TR 1021467 through a NRC safety evaluation (ADAMS Accession No. ML11262A206) for determining the technical adequacy of the PRA for RI-ISI. Please review your analysis and address any outstanding supporting requirements for this application by using guidance found in the safety evaluation that references EPRI TR 1021467.

Luminant Power's Response to Question 1:

Electric Power Research Institute (EPRI) Topical Report (TR) 1021467.was issued around the time of this submittal. An earlier document, TR 1018427 was used in preparation of the submittal to address supporting requirements. A comparison was performed of these two documents with.regards to Capability Category guidance (EPRI Traditional RI-ISI - Table 2.1 and 2.2 of each document). The only difference that was identified between the two documents was the removal of Internal Flooding (IF),

supporting requirements from the later EPRI document - TR 1021467.

The NRC staff has reviewed EPRI TR 1021467 and concludes that the TR, as modified by the conditions and limitations and applicant/licensee action items summarized in Section 4.0 of this Safety Evaluation (SE), provides reasonable assurance that the PRA has sufficient quality to support the development of 'an, RI-ISI program. These conditions and limitations can be placed into two groupings, the first was a .

revised justification for a lower capability category (CCI or "not-met" assignment) and the second was an increase in two SR's capability categories (CCII from CCI). A review of the NRC Safety Evaluation Report (SE for TR 1021467 dated 9-30-11 ML11262A206) attachment 1, table I identified SR AS-A9 and SC-B2 as those whose category had changed (increased). The CPNPP PRA model self assessment of these supporting requirements indicates that they met or exceed capability category II; no gap identified. The revised justification discussed in the SE and table 1 for the remainder of the SRs did not impact the capability category of those SRs.

Therefore, there are no additional outstanding supporting requirements for this application in the reference EPRI TR 1021467 as modified by the NRC's safety evaluation.

Attachment to TXX-12014 Page 2 of 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR RELIEF REQUEST NUMBER A-1 FOR THE UNIT 1 THIRD 10 YEAR ISI INTERVAL (THIRD INTERVAL START DATE: AUGUST 13, 2010) (TAC NO. ME6827)

NRC Question 2:

The licensee noted that two supporting requirements (SY-A22 and DA-C15) of the American Society of Mechanical Engineers (ASME) standard (ASME RA-Sb-2005) as provided by PRA technical adequacy guidance in EPRI TR 1018427 are related to the use of hardware fault recovery. DA-C15 and SY-A22 are not related in this standard. In ASME RA-Sb-2005, DA-C15 pertains to data on recovery of plant-specific initiating events while SY-A22 addresses repair of hardware faults. Please provide additional justification that disposition DA-C15 for this application.

Luminant Power's Response to Question 2:

We agree that the two supporting requirements (SR) are not related. The gap identified in the submittal relates to SY-A22 and should not have been tied to SR DA-C15. The ASME standard ties SR DA-C14 to SY-A22 and the table in the submittal should have reflected that relationship. Both of these SRs, SY-A22 and DA-C14, relate to modeling of repair of hardware faults and its justification. The CPNPP assessment identified these SRs as "not-met". Recovery of failures other than offsite power is not generally accepted or supported by data. Further it identified that CPNPP had not collected and analyzed plant specific data associated with the recovery of hardware faults. 'The sensitivity study provided inthe submittal for SY- .

A22 (Appendix 1, table item #1) anddits~conclusion provide the justification for use of the PRA model for this.application; (with respect to SRs SY-A22 and.DA-C14)_and no additional information is required.

DA-C15 supporting requirement should have read:as found to be met; no, gap identified (spans all'three capability categories). The basis for meeting the SR is that plant specific recovery data was used,in developing. the probability of -the mean time to repair (MTTR). factor applied to the.CCW, CH, ahd,SW,,'. i SSIE models. The. MTTR was;calculated based on~repair time, information for components in the three system initiator trees based on a review of maintenance rule-data. This recovery was used to account for - .!

• the probability that a failed component in one train could be repaired before a component in the other:.

train of the samesystem failed. . .