CP-201300002, Response to Request for Additional Information for Unit 1 Relief Request No. C-2

Response to Request for Additional Information for Unit 1 Relief Request No. C-2

ML13025A260
Person / Time
Site:	Comanche Peak
Issue date:	01/09/2013
From:	Madden F Luminant Power, Luminant Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201300002, TAC ME9409, TXX-13003
Download: ML13025A260 (4)

Text

Rafael Flores Luminant Power Senior Vice President P 0 Box 1002

& Chief Nuclear Officer 6322 North FM 56 Rafael.Flores@Luminant.com Glen Rose, TX 76043 Luminant 2548975550 C 817 559 0403 F 254 897 6652 CP-201300002 Ref. # 10CFR50.55a Log # TXX-13003 January 9, 2013 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 UNIT 1 RELIEF REQUEST NO. C-2 (TAC NO. ME9409)

REFERENCES:

1. Letter logged TXX-12129 dated August 23, 2012 from Rafael Flores to the NRC submitting Relief Request No. C-2 for the Unit 1 Reactor Pressure Vessel Leak-Off Flange (Third Interval Start Date: August 13, 2010).

2. Email dated December 10, 2012 from Balwant Singal of the NRC to Timothy Hope of Luminant Power requesting additional information regarding Relief Request No. C TAC ME9409.

Dear Sir or Madam:

Per reference 1, Luminant Generation Company LLC (Luminant Power) previously submitted a request for relief for inspection of the Unit 1 reactor pressure vessel leak-off flange. Per reference 2, the NRC provided a request for additional information regarding the subject relief request.

Attached is the Luminant Power response to the request for additional information.

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.

Sincerely, Luminant Generation Company LLC Rafael Flores _J By: /& ~2K2'/L

/ Fred W. MDadden" Director, Oversight & Regulatory Affairs A member of the STARS Alliance Callaway

• Comanche Peak - Diablo Canyon

• Palo Verde - San Onofre - South Texas Project

• Wolf Creek 10E q ý

U. S. Nuclear Regulatory Commission TXX-13003 Page 2 of 2

Attachment:

Response to Request for Additional Information for Relief Request C-2

Enclosure:

Drawings for Response toRAI Question 2 c- E. E. Collins, Region IV Luis Ponce B. K. Singal, NRR Texas Department of Licensing and Regulation Resident Inspectors, Comanche Peak P. 0. Box 12157 Jack Ballard, ANII, Comanche Peak Austin, Texas 78711-2332

Attachment to TXX-13003 Page 1 of 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR RELIEF REQUEST NUMBER C-2 FOR THE UNIT 1 THIRD 10 YEAR ISI INTERVAL (THIRD INTERVAL START DATE: AUGUST 13, 2010) (TAC NO. ME9409)

NRC Question 1 from Reference 2 Please state what is the CPNPP, Unit 1 third 10-year inservice inspection interval scheduled end date?

Luminant Power's Response to Question 1 August 12, 2020 is the end date for the third Unit 1 10-year inservice inspection interval.

NRC Question 2 from Reference 2 Please provide a piping and instrumentation diagram (P&ID) and a piping isometric drawing showing the subject flange leak-off line.

Luminant Power's Response to Question 2 The leak-off line numbers are:

• 3%-RC-1-080-2501R-2

• %-RC-1-081-2501R-2

• 3/4-RC-1-082-2501R-2

• 3/8-2505-2 (Tubing)

The flow diagram for these lines is ISI-Ml-0250-2.

The isometric drawings for these lines are: BRP-RC-1-RB-038, 39, 40, and 41.

These five drawings are provided in the enclosure to TXX-13003.

NRC Question 3 from Reference 2 Please state the material of construction of the leak-off line.

Luminant Power's Response to Question 3 The material of construction of the leak-off line is SA376 Type 304 or 316 Stainless Steel.

NRC Question 4 from Reference 2 Please describe the CPNPP, Units 1 and 2 experience with degradation (corrosion, stress corrosion cracking, fatigue, etc.) of these lines.

Luminant Power's Response to Question 4 There has been no known evidence of corrosion, stress corrosion cracking, fatigue, etc. in the subject flange leak-off piping at Comanche Peak. Also, a word search for the lines in question in the Comanche Peak Condition Report database returned no known historical instances of degradation.

Attachment to TXX-13003 Page 2 of 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FOR RELIEF REQUEST NUMBER C-2 FOR THE UNIT 1 THIRD 10 YEAR ISI INTERVAL (THIRD INTERVAL START DATE: AUGUST 13, 2010) (TAC NO. MP-9409)

NRC Question 5 from Reference 2 The proposed alternative would utilize the fluid head of the refueling water to pressurize the leak-off line prior to a VT-2 examination.

a. Please state the fluid head pressure that exists in the line when the refueling cavity has been filled to its normal refueling water level?

b. In order for a leak to be observed, sufficient time must have elapsed between the time that the line was pressurized and the time that the examination is performed. Please specify the minimum time between the time that the refueling cavity has been filled to its normal refueling water level and the VT-2 examination is performed.

Luminant Power's Response to Question 5.a The elevation of the Reactor Vessel flange is 834'-0 11/2". The elevation of the water level when the cavity is flooded is 858'-6". Therefore, the minimum pressure at the opening of the flange leak off line when the exam is performed is 24'-5 11/2" of static pressure head or 10.6 psi.

Luminant Power's Response to Ouestion 5.b Per 10CFR50.55a(b)(2)(xx)(A) when performing system leakage tests in accordance with IWA-5213(a) the licensee shall maintain a 10-minute hold time after test pressure has been reached for Class 2 components that are not in use during normal operating conditions. The subject lines are also not insulated.

NRC Ouestion 6 from Reference 2 Please discuss whether the line could be pressurized and inspected at the beginning of an outage before removing the head.

Luminant Power's Response to Question 6 As stated in Section 4 of Relief Request C-2, pressurizing the leak-off lines with an external source with the head installed would cause the inner o-ring to be put in a condition opposite of design likely causing damage and o-ring failure. This inner o-ring failure would prevent pressure build-up by allowing water to pass by and enter the reactor vessel. To ensure that it was in fact'an o-ring failure and not a leak in the leak-off line piping, the portion of piping in the reactor vessel nozzle inspection areas ("sandboxes")

would have to be inspected. The conditions inside the "sandboxes" at the beginning of the outage prior to removing the head would be considered unsafe with extremely high temperatures and dose rates ranging from 150 to 250 mRem/hr. The leak-off piping travels through three of the eight "sandboxes". It is felt that performing the examination in this manner would result in an unnecessary hardship without a sufficient compensating increase in the level of quality and safety.