Text

Response Update to Generic Letter 2004-02: Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors
	ML061570193
Person / Time
Site:	Callaway
Issue date:	05/30/2006
From:	Keith Young; AmerenUE
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	GL-04-002, ULNRC-05295
	Download: ML061570193 (7)
	v • d • e

AmerenUE PO Box 620 Callaway Plant Fulton, MO 65251 May 30, 2006 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 ULNRC-05295 WAmeren Ladies and Gentlemen:

UiE DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

FACILITY OPERATING LICENSE NPF-30 RESPONSE UPDATE TO GENERIC LETTER 2004-02:

"POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS"

References:

1. ULNRC-05194, dated September 1, 2005.

2. NRC letter dated March 28, 2006, from Catherine Haney, NRC, to Holders of Licenses for Pressurized-Water Reactors.

In accordance with 10 CFR 50.54(f), this letter provides an update to the Union Electric Company (AmerenUE) response to Nuclear Regulatory Commission (NRC)

Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors."

The NRC issued Generic Letter 2004-02 on September 13, 2004 to 1) request that addressees perform an evaluation of the Emergency Core Cooling System (ECCS) and Containment Spray System (CSS) recirculation functions in light of the information provided in the generic letter and, if appropriate, take additional actions to ensure system function, and 2) require addressees to provide the NRC a written response in accordance with 10 CFR 50.54(f).

Reference 2 transmitted the NRC's alternative approach for responding to the NRC request for additional information letter on Generic Letter 2004-02. The agreed alternative to the 60 day response is that for plants installing strainers after 2006, a subsidityofAmeren Cqioramion

ULNRC-05295 May 30, 2006 Page 2 information needed to fully address GL 2004-02 will be provided to the NRC within 90 days of outage completion but not later than December 31, 2007.

Reference 1 provided the available information requested by Generic Letter 2004-02 and committed to update that information by June 1, 2006. To address the generic letter and associated commitments, the activities described below have taken place thereafter. Specific commitments are addressed in Attachment 1. During the week of March 13, 2006, mock up strainer head loss testing was performed. Analysis of the results is ongoing. Activities are proceeding as described in Reference I and are outlined in Attachment 1 of this submittal. Specifically, AmerenUE plans to install new containment recirculation sump strainers at Callaway to increase the available (i.e., submerged) strainer area from less than 400 square feet currently available to an expected area of approximately 6400 square feet. Any additional information needed to fully address the generic letter will be provided to the NRC 90 days after completion of Refuel 15 (spring 2007) as established in the request for additional information (RAI) schedule provided in Reference 2.

This letter transmits changes in AmerenUE regulatory commitments contained in Reference 1. The commitment changes are being submitted in accordance with guidance provided by industry document NEI 99-04, "Guidelines for Managing NRC Commitment Changes," as endorsed in Regulatory Issues Summary 00-017, "Managing Regulatory Commitments Made by Power Reactor Licensees to the NRC Staff." Attachment 1 lists the AmerenUE commitments contained in this letter.

Commitments contained in this letter supersede those previously contained in Reference 1.

If you have any questions concerning this matter, please contact Dave Shafer at (314) 554-3104.

I declare under penalty of perjury that the foregoing is true and correct.

Sincerely, Executed on: May 30, 2006 Keith D. Young Manager - Regulatory Affairs BFI/ Updated List of Commitments

a 0£ ULNRC-05295 May 30, 2006 Page 3 CC: Mr. Bruce S. Mallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O-7D1 Washington, DC 20555-2738 Missouri Public Service Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360 Mr. Ron Reynolds Director Missouri State Emergency Management Agency P.O. Box 116 Jefferson City, MO 65102

ULNRC-05295 Page 1 of 4 LIST OF COMMITMENTS The following table identifies those actions originally committed to by AmerenUE in Reference 1. The table provides a status update and revised commitment due dates. Please direct questions regarding these commitments to Mr. David E. Shafer at (314) 554-3104.

.COMMITMENT Current Status Due Date/Event

1. Containment walkdown to provide current assessment Completed during Refuel Outage 14 (Fall 2005).

of Callaway's containment coatings and latent debris.

2 The following corrective action activities will be Within 90 days of completed: Refuel 15

a. Replacement sump strainer structural analysis. The structural analysis of the replacement strainers is in completion (spring progress and will be completed prior to Refuel 15 (Spring 2007) 2007).

b. Downstream effects evaluation. Initial downstream evaluations have been performed; however, refinements are being pursued using test data and input from PWROG/NRC discussions concerning nuclear fuel.

c. Upstream effects evaluation. Upstream evaluations have been performed and will be included in the Westinghouse team analysis summary report, item 4.f. of this table.

d. Resolution of debris generation calculation Zone of influence testing has been performed and a draft unverified assumption of 5D ZOI for qualified report was issued in May 2006.

coatings (via coatings testing).

e Replacement sump screen head loss testing. Strainer performance testing, including provisions for chemical effects, was performed during the week of March 13, 2006.

ULNRC-05295 )

Page 2 of 4

3. Provide an update of the information contained in The analyses are proceeding and refinements are being December 31, 2007 section 2(c) regarding analysis methodology, pursued. The update of information contained in section 2(c) of Reference 1 will be provided after completion of Item 4.f. of this table.

4. The following evaluations and testing will be Within 90 days of completed: Refuel 15

a. Industry chemical effects testing. Industry chemical effects tests have been completed. completion (spring 2007)

b. NEI 04-07 debris generation calculation. The debris generation calculation has been performed and will be included in the Westinghouse team analysis summary report, item 4.f. of this table.

c. NEI 04-07 debris transport calculation. The debris transport calculation has been performed and will be included in the Westinghouse team analysis summary report, item 4.f. of this table.

d. Evaluation of chemical effects impact on sump- WCAP 16530-NP guidance was used as part of the strainer strainer head loss. performance testing performed during the week of March 13, 2006.

e. Confirmation that the replacement sump strainer The strainer performance test report is in progress and will design provides for available NPSH to be in excess be used in the determination of adequate NPSH.

of required NPSH.

f. Completion of the final site acceptance review of Several of the items contained in the final report have been the Westinghouse team analysis summary report. completed but the final report will not be issued until all items are completed.

ULNRC-05295 Page 3 of 4

- F

5. Callaway will complete the following items during Prior to restart from Refuel 15: Refuel Outage 15

a. Replacement of containment recirculation sump Activities are proceeding to install the new strainers during (Spring 2007) strainers. Refuel 15 (Spring 2007).

b. Modification of containment debris barriers and Debris barriers are currently planned for installation during interceptors as required. Refueling Outage 15. Use of debris interceptors is dependant on the refinements mentioned in Item 2.b. of this table.

c Evaluation and implementation of potential Implementation of potential modification to the safety modification to the safety injection system to injection system is dependant on the refinements address downstream effects. mentioned in Item 2.b. of this table.

6. Callaway will complete removal of containment spray Removal of containment spray system (CSS) pump December 31, 2007 system (CSS) pump cyclone separators, if required cyclone separators is dependent on the results of the based on the results of the downstream effects downstream effects evaluation, Item 2.b. of this table.

evaluation.

7. The following programs and controls will be Evaluations of changes required to programs and controls December 31, 2007 implemented at Callaway to control debris sources. have not been completed.

a. Changes to design change process procedures to ensure that necessary engineering evaluations will be performed for plant design that either directly or indirectly affects containment, ECCS, or CSS.

b. Changes to containment entry and material control procedure requirements for control of materials during work activities conducted in the containment.

c. Changes to programs and procedures that have the potential to add tags and labels inside containment.

ULNRC-05295 Page 4 of 4

7. (continued)

d. Implementation of a containment coatings assessment program

e. Implementation of a containment latent debris assessment program f Implementation of changes to the inspection processes for the installed sump strainers

8. A final response will be submitted to the NRC to December 31, 2007 provide a final status of actions requested by Generic Letter 2004-02.