CP-201001544, Relief Request No. C-9 for the Second 10 Year Interval from 10 CFR 50.55a Inspection Requirements Due to Hardship (Second Interval Start Date: August 13, 2000)

Relief Request No. C-9 for the Second 10 Year Interval from 10 CFR 50.55a Inspection Requirements Due to Hardship (Second Interval Start Date: August 13, 2000)

ML103560595
Person / Time
Site:	Comanche Peak
Issue date:	12/15/2010
From:	Madden F Luminant Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201001544, TXX-10156
Download: ML103560595 (8)

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 T 254 897 5550 C 817 559 0403 F 254 897 6652 CP-201001544 Ref. # 10 CFR 50.55a(a)(3)(ii)

Log # TXX-10156 December 15, 2010 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK NUCLEAR POWER PLANT DOCKET NO. 50-445 RELIEF REQUEST NO. C-9 FOR THE UNIT 1 SECOND 10 YEAR ISI INTERVAL FROM 10 CFR 50.55a INSPECTION REQUIREMENTS DUE TO HARDSHIP (SECOND INTERVAL START DATE: AUGUST 13, 2000)

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(a)(3)(ii), Luminant Generation Company, LLC (Luminant Power) is submitting Relief Request C-9 (see attachment) for Comanche Peak Unit 1 for the second ten year inservice inspection interval. Luminant Power has determined that compliance with certain inspection requirements of ASME Section XI would result in an unnecessary hardship without a sufficient compensating increase in the level of quality and safety.

The Reactor Pressure Vessel flange leak-off piping configuration precludes system pressure testing when the reactor vessel head is removed. The configuration also precludes pressurizing the line externally when the head is installed. A visual examination of the accessible areas was performed during the second interval on the unpressurized subject piping as part of the Class 2 leakage test. No evidence of leakage has been identified for the subject component. No undue risk to the public health and safety is presented by this request.

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-10156 Page 2 12/15/2010 This communication contains no new licensing basis commitments 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 By: A4~ ?227L_

Ared W. Madden Director, Oversight & Regulatory Affairs Attachments - 1. Relief Request C-9 for Alternate Pressure Testing Requirements for the Reactor Pressure Vessel Flange Leak-off Piping

2. Reactor Pressure Vessel Seal Leak-off Details c- E. E. Collins, Region IV B. K. Singal, NRR Resident Inspectors, Comanche Peak Brian Welch, ANII, Comanche Peak Anthony Jones, TDLR to TXX-10156 Page I of 3 10CFR 50.55a Request Number C-9 Proposed Alternative In Accordance with 10CFR50.55a(a)(3)(ii)

- Hardship. or Unusual Difficulty without a Compensating Increase in Level of Quality or Safety -

/

1. ASME Code Components Affected:

ASME Code Class: Code Class 2

References:

ASME Section XI, Table IWC-2500-1 and IWC-5222 Examination Category: C-H (All Pressure Retaining Components Item Number: C7.10

Description:

Alternative Pressure Testing Requirements for the RPV Flange Leak-Off Piping Component: NPS 3/4/4" RPV Flange Seal Leak-Off Piping Line Numbers: BRP-RC- 1-RB-038, BRP-RC-1-RB-039, BRP-RC- 1-RB-040, BRP-RC- 1-RB-041, MI -0250

2. Applicable Code Edition and Addenda

ASME Section XI, 1998 Edition through 2000 Addenda.

3. Applicable Code Requirement

IWC-2500, Table IWC-2500-1, Code Category C-H, Item Number C7.10 requires that all Class 2 pressure retaining components be subject to a system leakage test with a Visual, VT-2 examination each inspection period. The system leakage test is performed at the pressure obtained while the subject portion of the system is performing its normal operating function or during a comparable test.

Per IWC-5222(a), the pressure retaining boundary includes the portion of the system required to operate or support the safety function up and including the first normally closed valve.

4. Reason for Request

As discussed in 3, "Applicable Code Requirements," ASME Section XI, 1998 Edition, 2000 Addenda requires that Class 2 pressure boundary piping shall be pressure tested once each inspection period. The Reactor Pressure Vessel (RPV) head flange seal leak detection piping is separated from the reactor coolant pressure boundary by one passive membrane, which is an O-ring located on the inner vessel flange as shown in Attachment 1. A second O-ring is located on the outside of the tap in the vessel flange. Failure of the inner o-ring is to TXX-10156 Page 2 of 3 10CFR 50.55a Request Number C-9 the only condition under which this line is pressurized. Therefore, the line is not expected to be pressurized during the system pressure test following a refueling outage.

The configuration of this piping precludes system pressure testing while the vessel head is removed because the time required by personnel for the installation and removal of a threaded plug in the flange face to act as a pressure boundary for the test would incur significant dose (estimated 20 - 40mR/min), which would be an ALARA concern. This activity would also present a Foreign Material Exclusion issue for the 1/8" plug that would required to be installed to complete a leakage test at pressure.

The configuration also precludes pressurizing the line externally with the head installed.

The top head of the vessel contains two grooves that hold the o-rings. The o-rings are held in place by a series of retainer clips that are housed in recessed cavities in the flange face.

If a pressure test were to be performed with the head on, the inner o-ring would be pressurized in a direction opposite to its design function. This test pressure would result in a net inward force on the inner o-ring that would tend to push it into the recessed cavity that houses the retainer clips. The thin o-ring material would likely be damaged by the inward force.

Purposely failing or not installing the inner o-ring in order to perform a pressure test would require purchasing a new o-ring set and the time and radiation exposure associated with removing and reinstalling the RPV head to replace the o-rings would be an undue hardship.

Therefore, compliance with the IWC-5222(b) system pressure test requirements results in an unnecessary hardship without a sufficient compensating increase in the level of quality and safety.

5. Proposed Alternative and Basis for Use:

In lieu of the requirements of IWC-5222(b), a VT-2 visual examination of the accessible areas will be performed each period on the piping subjected to the static pressure head when the reactor cavity is filled. This test will be part of the reactor coolant Class 2 leakage test.

If the inner o-ring should leak during the operating cycle it will be identified by an increase in temperature of the leak-off line above ambient temperature. This high temperature would actuate an alarm in the Control Room, which would be closely monitored by procedurally controlled operator actions allowing identification of any further compensatory actions required. This leakage would be collected in the Reactor Coolant Drain Tank.

Additionally, the flange seal leak-off line is essentially a leakage collection/detection system and the line would only function as a Class 2 pressure boundary if the inner o-ring fails, thereby pressurizing the line. If any significant leakage does occur in the leak-off line piping itself during this time of pressurization then it would clearly exhibit boric acid to TXX-10156 Page 3 of 3 10CFR50.55a Request Number C-9 accumulation and be discernable during the proposed VT-2 visual examination that will be performed unpressurized as proposed in this request.

6. Duration of Proposed Alternative:

This relief is requested for the duration of the Second Inservice Inspection Interval, which began on August 13 2000, and ended on Aug 12, 2010.

7. Precedents:

LaSalle County Station Third Inspection Interval Relief Request 13R-08.

"Pressure Testing of the Reactor Vessel Head Flange Leak Detection System", as approved by the NCR in a letter dated January 30, 2008, Ref. ML073610587.

Susquehanna Steam Electric Station Third 10-Year Inservice Inspection (ISI) Interval Program Plan Request for Relief 3RR-07 "Exemption for Pressure Testing Reactor Pressure Vessel Head Flange Seal Leak Detection System", approved by the NRC in a letter dated September 24, 2004, Ref ML042680078 The following precedents were for same lines that were designated Class 1.

Millstone Power Station Unit 3 Relief Request IR 11, "Alternative Pressure Testing Requirements for the RPV Flange Leak-Off Piping", approved by the NRC Letter dated April 29, 2010, ADAMS Accession No. ML101040042.

North Anna Unit 1 Relief Request SPT-013, "Examination Category B-P Pressure Retaining Components in the Reactor Coolant System," approved by NRC letter dated February 9, 2006, ADAMS Accession No. ML060450517 Limerick Second Interval Relief Request RR-33, "Pressure Testing of the Reactor Vessel Head Flange Leak Detection System (Unit 1 only))", (ADAMS Accession Nos.

ML080370257, ML082550270 and ML090060218), as approved by the NRC in a letter dated January 27, 2009.

Limerick Third Interval Relief Request 13R-08, "Reactor Pressure Vessel (RPV) Head Flange Seal Leak Detection System Pressure Testing", (ADAMS Accession No. ML080500584) as approved by the NRC in a letter dated March 11, 2008.

to TXX- 10156 Page 1 of3 Reactor Pressure Vessel Seal Leak-Off Details Luminant Comanche Peak to TXX-10156 Page 2 of 3 Figure 1:

REACTOR PRESSURE VESSEL HEAD FLANGE LEAK-OFF LINE CONFIGURATION to TXX-10 156 Page 3 of 3 Figure 2 Reactor Pressure Vessel Head Flange Leak-Off Line Details