ML093240521
| ML093240521 | |
| Person / Time | |
|---|---|
| Site: | Kewaunee  |
| Issue date: | 11/20/2009 |
| From: | Price J Dominion Energy Kewaunee |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 09-675, GL-08-001 | |
| Download: ML093240521 (4) | |
Text
1)Olllillion Energy Kewaunee, Inc.
(Hi; I I )omin;on Boulevard, Glen Allel1, VA,'
November 20, 2009 ATTN: Document Control Desk U, S. Nuclear Regulatory Commission Washington, DC 20555-0001 Dominion Serial No. 09-67~5 L1C/NW/R2 Docket No.: 50-:305 License No.: DPR:-43 DOMINION ENERGY KEWAUNEE, INC.
KEWAUNEE POWER STATION NOTIFICATION OF COMMITMENT CHANGE REGARDING GENERIC LETTER 2008-01. ELIMINATION OF GAS ACCUMULATIONS On January 1, 2008, the NRC issued Generic Letter (GL) 2008-01 (reference 1),
requesting that each licensee evaluate the licensing
- basis, design,
- testing, and corrective action programs for the emergency core cooling systems (ECCS), residual heat removal system (RHR),
and containment spray system to ensure that gas accumulation is maintained less than the amount that challenges operability of these systems. The GL also requested that licensees take appropriate action when conditions adverse to quality are identified as a result of the evaluations.
Dominion Energy Kewaunee, Inc. (DEK) submitted a response to GL 2008-01 on October 14, 2008 (reference 2) for Kewaunee Power Station (KPS).
In the response, DEK committed to either eliminate gas accumulations that were found during UT examinations of the subject systems prior to the end of the next refueling outage KH 30 (fall 2009), or to revise design basis documents to establish new allowable design basis limits on gas accumulation.
The purpose of this letter is to notify the NRC of a change to the above commitment.
Specifically, DEK has extended the completion date for a specific portion of the commitment regarding elimination of gas accumulations found during the 2008 UT examinations of the subject systems.
Out of the total number of locations where gas accumulations were identified in the subject systems at KPS, voids in three sections of ECCS piping have neither been eliminated nor accepted by revision to design basis documents. These piping sectilons and a short discussion of the circumstances are as follows:
- 1. Chemical and volume control system (CVCS) to RHR cross-connect piping from the RHR discharge piping:
Repairs to a valve (LD-60) were performed during the most recent refueling outage.
This valve was suspected to be leaking from the letdown system to the RHR system and causing the void. However, after returning to the at-power lineup after the most recent refueling outage, gas voiding was still found in a 2-inch
Serial No. 09-*675 Page.2 of 4 section of pipe downstream of LD-60.
It is now suspected that another valve (RHR-44, a check valve that bypasses LD-60) is leaking. RHR-44 was replace'd in KR 29 and therefore was not suspected to be leaking. A cold shutdown outagle is necessary to perform work on this valve.
- 2. Suction bypass branch to the safety injection (SI) suction piping:
A vent valve was installed in this piping during the most recent refueling outage.
After the system was refilled, it was determined that a void was present. The new void is smaller than the old void, but lar~er than the established acceptance criteria for considering the piping full (0.01 ft).
Elimination of the remaining void may require modification that can only be done during a cold shutdown outage.
A vent valve was installed during the most recent refueling outage.
A UT examination indicated the void is currently eliminated.
However, based on the operating characteristics of the system, DEK expects that voiding may reappear at this location sometime during the next operating cycle as the RHR system stands at low pressure. DEK suspects that some gas is being absorbed into the watE~r in the piping during RHR system operation and may re-appear as the system stands at low pressure. Additional corrective actions may be necessary to ensure that this piping remains free of voids.
As discussed above, efforts to eliminate the existing voids from these three locations during the previous refueling outage were not completely successful.
However, the sizes of the gas voids in these piping sections have been significantly reduced from those that existed during the previous operating cycle.
The gas voids that existed during the previous operating cycle have been determined not to impact system operability and therefore the piping remains operable with the smaller voids.
Periodic monitoring has been instituted to ensure the total accumulation of gas is controlled and does not exceed operability limits.
Elimination of the remaining voids may require additional modifications, which can only be performed with the unit in a shut down condition.
DEK has determined that extending the completion time of the remaining corrective actions to the next refueling outage is acceptable, since the remaining voids do not adversely impact system operability and monitoring and control measures have been implemented.
Therefore, the completion date to eliminate gas accumulations from the three sections of piping discussed above has been revised from the end of refueling outage KR 30 (fall 2009), to the end of refueling outage KR 31 (spring 2011).
~ ()jJg.)
No ary Public Serial No.09-675 Page 3 of 4 If you have questions or require additional information, please feel free to contact Mr.
Jack Gadzala at 920-388-8604.
Very truly yours, J.
Price Vi resident - Nuclear Engineering Dominion Energy Kewaunee, Inc.
COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by J. Alan Price, who is Vice President - Nuclear Engineering of Dominion Energy Kewaunee, Inc.
He has affirmed before me that he is duly authorized to execute and file the foregloing document in behalf of that Company, and the statements in the document are true to the best of his knowledge and belief.
Acknowledged before me this ~ay of Novt.-m bt/
,2009.
My Commission expires:
4\\00\\\\3
References:
- 1. NRC Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," dated January 11, 2008.
2.
Letter from J. Alan Price (DEK) to Document Control Desk (NRC), "Nine-Month
Response
to NRC Generic Letter 2008-01, Managing Gas Accumulation In Emergency Core Cooling, Decay Heat Removal, And Containment Spray Systems,"
dated October 14, 2008 (ADAMS Accession No. ML082880707).
Serial No. 09-*675 Page 4 of 4 Commitments made by this letter:
The completion date for a portion of the commitment to eliminate gas accumulatiions that were found during UT examinations of the subject systems is revised as follows:
DEK will take actions needed to resolve the gas accumulations at the following locations.
CVCS-RHR cross-connect piping from the RHR discharge piping Suction bypass branch to the SI suction piping RHR-to-Spent Fuel Pool interconnection branch line from the RHR discharge piping Resolution may include installation of additional vent valves, procedure modifications to ensure systems are sufficiently filled after draining for maintenance, or revision of design basis documents to establish new allowable design basis limits on gas accumulation.
These actions will be completed by the end of refueling outage KR. 31 (Spring 2011).
cc:
Regional Administrator, Region III U. S. Nuclear Regulatory Commission 2443 Warrenville Road Suite 210 Lisle, IL 60532-4352 Mr. P. S. Tam Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08-H4A 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Kewaunee Power Station