GO2-12-171, Proposed Alternative to Utilize Code Case N-795, Alternative Requirements for BWR Class 1 System Leakage Test Pressure Following Repair/Replacement Activities, Section XI, Division 1

Proposed Alternative to Utilize Code Case N-795, Alternative Requirements for BWR Class 1 System Leakage Test Pressure Following Repair/Replacement Activities,Section XI, Division 1

ML12340A066
Person / Time
Site:	Columbia
Issue date:	11/27/2012
From:	Javorik A Energy Northwest
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GO2-12-171
Download: ML12340A066 (6)

Text

ENERGY

," * - Columbia Generating L.Station Alex Javorik P.O. Box 968, PEO4 Richland, WA 99352-0968 Ph. 509.377.8555 1F. 509.377.2354 aljavorik@ energy-northwest.com November 27, 2012 G02-12-171 10 CFR 50.55a U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001

Subject:

COLUMBIA GENERATING STATION, DOCKET NO. 50-397 PROPOSED ALTERNATIVE TO UTILIZE CODE CASE N-795, "ALTERNATIVE REQUIREMENTS FOR BWR CLASS 1 SYSTEM LEAKAGE TEST PRESSURE FOLLOWING REPAIR/REPLACEMENT ACTIVITIES, SECTION XI, DIVISION 1"

Dear Sir or Madam:

Columbia Generating Station (Columbia) is requesting approval for the use of ASME Code Case N-795, "Alternative Requirements for BWR Class 1 System Leakage Test Pressure Following Repair/Replacement Activities,Section XI, Division 1 ," as an alternative to the system leak test pressure requirement of IWB-5221 (a). Approval of Code Case N-795 for use at Columbia would reduce personnel exposure and abnormal system lineups which would otherwise be required.

There are no commitments being made to the NRC by this letter. If you have any questions or require additional information regarding this matter, please contact Zach Dunham, Licensing Supervisor, at (509) 377-4735.

Respectfully, A.L. Javorik Vice President, Engineering Enclosure (1) cc: NRC RIV Regional Administrator NRC NRR Project Manager NRC Senior Resident Inspector/988C AJ Rapacz - BPA/1 399 WA Horin - Winston & Strawn J cL "l

ENCLOSURE 1 PROPOSEDALTERNATIVE TO UTILIZE CODE CASE N-795, ALTERNATIVE REQUIREMENTS FOR BWR CLASS 1 SYSTEM LEACKAGE TEST PRESSURE FOLLOWING REPAIR/REPLACEMENT ACTIVITIES, SECTION XI, DIVISION 1

PROPOSED ALTERNATIVE TO UTILIZE CODE CASE N-795, ALTERNATIVE REQUIREMENTS FOR BWR CLASS 1 SYSTEM LEACKAGE TEST PRESSURE FOLLOWING REPAIR/REPLACEMENT ACTIVITIES, SECTION XI, DIVISION 1" Page 1 of 4 Columbia GeneratingStation Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(ii)

Relief Request Number 31S1-12 Hardship or Unusual Difficulty without Compensating Increase in Level of Quality or Safety

1. ASME Code Component(s) Affected All American Society of Mechanical Engineers (ASME)Section III Class 1 system components.

2. Applicable Code Edition and Addenda Columbia Generating Station (Columbia) is committed to the ASME Boiler and Pressure Vessel Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components, "(ASME Section XI), 2001 Edition with the 2003 Addenda (Reference 1).

3. Applicable Code Requirement

The 2001 Edition with the 2003 Addenda references IWB-5220 SYSTEM LEAKAGE TEST, IWB-5221 (a), which requires the system leakage test to be conducted at a pressure not less than the pressure corresponding to 100% rated reactor power (1020 psig for Columbia) on Class 1 components.

4. Reason for Request

Columbia requests the approval to use ASME Code Case N-795 (Reference 2) as an alternative to IWB-5221 (a) following repair/replacement activities on Class 1 items (excluding the reactor vessel). Class 1 pressure tests following repair/replacement activities on Class 1 items are required to be performed at 1,020 psig or higher at Columbia.

Performance of the VT-2 visual examinations during the IWB-5221 (a) pressure test with the plant at 100% power would result in high dose rates. High dosage rates pose personnel safety hazards that are contrary to As Low As Reasonably Achievable (ALARA) practices. Alternately, plant protective equipment could be manually altered to reach the IWB-5221 (a) test pressure at a lower power level.

However, operation of the plant at a lower power level with altered protective equipment places the plant in a state of undesirable operational risk due to reduced operating margins.

PROPOSED ALTERNATIVE TO UTILIZE CODE CASE N-795, ALTERNATIVE REQUIREMENTS FOR BWR CLASS 1 SYSTEM LEACKAGE TEST PRESSURE FOLLOWING REPAIR/REPLACEMENT ACTIVITIES, SECTION XI, DIVISION 1" Page 2 of 4 Performance of the VT-2 visual examinations during the IWB-5221 (a) pressure test while the plant is in a shutdown condition requires either re-performance of the refueling outage Table IWB-2500-1 Category B-P system leakage test (Reactor Pressure Vessel (RPV) Leakage Test) or a customized local pressurization system leakage test. Both of these alternatives require abnormal plant system alignments that result in challenges to the plant and personnel.

Compliance with the IWB-5221 (a) pressure test requirements results in additional plant challenges and delays without benefit as compared to pressure tests performed at slightly reduced pressures with extended hold times. Performing the system leakage tests following repair/replacement activities at the IWB-5221 (a) required test pressure is not commensurate with the added dose benefit of allowing pressure testing and VT-2 visual examination at a low power level during normal plant startup procedures.

Use of ASME Code Case N-795 would allow Columbia to use normal plant procedures and system alignments at low power to meet the system leakage test requirements and minimize plant risk and personnel exposure.

5. Proposed Alternative and Basis for Use Columbia is requesting approval for the use of ASME Code Case N-795, approved by ASME on September 17, 2010, as an alternative to the system leak pressure test requirement of IWB-5221 (a). Code Case N-795 is provided below in its entirety:

Case N-795 Alternative Requirements for BWR Class 1 System Leakage Test Pressure Following Repair/Replacement Activities Section Xl, Division 1 Inquiry: What alternative to the pressure corresponding to 100% rated reactor power, of IWB-5221(a), may be used during a BWR Class 1 system leakage test following repair/replacement activities?

Reply: It is the opinion of the Committee that as an alternative to the pressure corresponding to 100% rated reactor pressure required by IWB-5221(a), the following requirements shall be met for a BWR Class 1 system leakage test, following repair/replacement activities.

(a) A system leakage test (IWB-5220) shall be conducted at a test pressure of at least 87% of the pressure required by IWB-5221 (a).

(b) The system shall be maintained at this pressure during the required hold time and the performance of the VT-2 visual examination, except as provided by IWA-5245.

PROPOSED ALTERNATIVE TO UTILIZE CODE CASE N-795, ALTERNATIVE REQUIREMENTS FOR BWR CLASS 1 SYSTEM LEACKAGE TEST PRESSURE FOLLOWING REPAIR/REPLACEMENT ACTIVITIES, SECTION XI, DIVISION 1" Page 3 of 4 (c) This alternative test pressure may not be used to satisfy the requirements of Table IWB-2500-1, Category B-P.

(d) This alternative test pressure may not be used to satisfy pressure test requirements following repair/replacement activities on the reactor vessel.

(e) A test condition holding time, after pressurization to test conditions, before the visual examinations commence, shall be as follows:

(1) 15 min holding time for noninsulated components (2)6 hr holding time for insulated components Code Case N-795 allows a reduction of 13% in the test pressure required by IWB-5221(a) with a required hold time 50% longer than that required by IWB-5000. The longer hold time at the lower permitted test pressure allows additional time for leakage to accumulate and be identified during the VT-2 examination.

The use of Code Case N-795 at Columbia would allow execution of system leakage tests and VT-2 visual examinations during normal plant startup conditions at low reactor power levels for some Class 1 repair/replacement activities located in containment. Existing plant procedures require containment entry with an accompanying drywell inspection which would allow performance of VT-2 visual examination during this drywell inspection at low power. This would result in reduced personnel exposure and avoid abnormal system lineups.

Based on the above discussion, Columbia has concluded that the use of Code Case N-795 as an alternate to the requirements of IWB-5221 (a) provides an acceptable level of quality and safety. Columbia therefore requests the approval for the use of Code Case N-795 as an alternate to the requirements of IWB-5221 (a) for the Class 1 system leakage test following repair/replacement activities. All other ASME Section Xl requirements for which relief is not being specifically requested, if authorized by NRC staff, will remain applicable including third party review by the Authorized Inspection Agency.

6. Duration of Proposed Relief Alternative Relief is requested for the Third Inspection Interval, from the date of relief approval through the end of the Third Inspection Interval on December 12, 2015.

7. Precedents A similar 10 CFR 50.55a relief request (Reference 3) was approved for Monticello Nuclear Power Plant during the Fourth 10-Year Inservice Inspection Interval as a one-time relief by NRC letter "Monticello Nuclear Generating Plant - One Time Inservice Inspection Program Plan Relief Request No. 8 for Leak Testing the "B" and "G" Main Steam Safety Relief Valves (TAC No. MB9538)", dated June 13, 2003.

PROPOSED ALTERNATIVE TO UTILIZE CODE CASE N-795, ALTERNATIVE REQUIREMENTS FOR BWR CLASS 1 SYSTEM LEACKAGE TEST PRESSURE FOLLOWING REPAIR/REPLACEMENT ACTIVITIES, SECTION XI, DIVISION 1" Page 4 of 4

8. References

1. Columbia Generating Station Inservice Inspection (ISI) Plan, Revision 5, Third Ten-Year Inspection Interval, beginning December 13, 2005 through December 12, 2015.

2. ASME Section XI Code Case N-795, "Alternative Requirements for BWR Class 1 System Leakage Test Pressure Following Repair/Replacement Activities,Section XI, Division 1."

3. NRC Safety Evaluation, NRC letter to NMC "Monticello Nuclear Generating Plant - One Time Inservice Inspection Program Plan Relief Request No. 8 for Leak Testing the "B" and "G" Main Steam Safety Relief Valves (TAC No. MB96380)", dated June 13,2003. (ADAMS Accession No. ML031640464).