ML20046B545
| ML20046B545 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/30/1993 |
| From: | Pelletier J VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BVY-93-78, IEB-93-003, IEB-93-3, NUDOCS 9308050116 | |
| Download: ML20046B545 (3) | |
Text
t YERMONT YANKEE NUCLEAR POWER CORPORATION Ferry Road, Brattleboro, VT 05301-7002 Q
ENGINEERING OFFICE N' '~'
580 MAIN STREET
- 's BOLTON MA 01740 '
(508) 779-6711 July 30,1993 BVY 93-78 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 -
References:
a)
License No. DPR-28 (Docket No. 50-271) b)
Letter, USNRC to VYNPC, NVY 93-23, dated March 30,1993 c)
NRC Bulletin 93-03, " Resolution of issues Related to Reactor Vessel Water Level instrumentation in BWRs", NVY 93-065, dated May 28,1993 d)
Letter, VYNPC to USNRC, BVY 93-57, dated June 9,1993
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Subject:
SHORT TERM COMPENSATORY ACTIONS AND - HARDWARE MODIFICATIONS REQUESTED IN NRC BULLETIN 93-03,
" RESOLUTION OF ISSUES RELATED TO REACTOR VESSEL WATER LEVEL INSTRUMENTATION IN BWRS"
Dear Sir:
Per Reference c), the NRC requested Vermont Yankee to submit a report by July 30,1993 providing the following information regarding reactor vessel water level instrumentation:
(a) the description of the short term compensatory actions taken, and (b) a description of the hardware modifications to be implemented at the next cold shutdown after July 30,1993.
With regard to (a) above, Vermont Yankee has implemented the Short Term Compensatory Actions 1(a) and 1(b) as described in Reference d).
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United States N 3ar Regulatory Commission July 30,1993 Page 2 Vermont Yankee has continued to assess the water level issue including the concerns of the NRC, as discussed in Reference c). We have stayed abreast of industry initiatives related to water level instrumentation including the activities of the BWR Owners Group. While we remain confident that the reactor vessel water level indication system as currently installed at Vermont Yankee is highly reliable and meets all design criteria, we believe it is prudent to further enhance the reliability of the water level indication system by installation of a hardware modification.
Therefore, in response to item (b), of Reference c) and Reference b), Vermont Yankee currently intends to install a reference leg backfill modification. Current plans are as follows:
1.
This modification will be installed on all four reactor vessel water level reference legs originating from two condensing chambers.
These reference legs include both safety and non-safety instruments and both trip and monitoring functions.
2.
The source of water to the reference legs is expected to be the charging i
water side of the Control Rod Drive (CRD) System. The existing 1" reference leg piping in the Reactor Building will be tapped near the l
drywell penetrations.
3.
Safety class valves will provide the class break between the non-safety CRD System and the safety class reactor vessel water level instrumentation systems. Means will be provided for leakage testing of safety class check valves.
4.
This modification will include the installation of flow metering valves and flow monitoring instrumentation. A new instrument rack and valve station will also be added.
5.
The required flow rate through the reference legs will be determined j
along with any effect on existing systems and instrumentation.
The design details of this modification are still under review. In addition, the final design still requires analysis by Vermont Yankee under the provisions of 10 CFR 50.59. These modifications are scheduled to be implemented during the 1993 i
refueling outage to begin in late A.ugust.
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voimm vun.wco.w rown, co wouuos United States Nuclear Regulatory Commission July 30,1993 Page 3 We trust that the information provided above adequately supports your requests, however, should you have any questions on this matter, please contact us.
Very truly yours, VERMONTYANKEE NUCLEAR POWER CORP.
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James P. Pelietier Vice President, Engineering cc:
USNRC Region l Administrator USNRC Resident inspector - VYNPS USNRC Project Manager - VYNPS STATE OF VERMONT
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Then personally appeared betore me, James P. Pelletier, who, being duly sworn, did state that he is vice President-Engineering, of Vermont Yankee Nuclear Power Corporation, that he is duly authorized to execute and file the foregoing document in the name and on the behalf of Vermont Yankee Nuclear Power Corporation, and that the statements therein are true to the best of his knowledge and belief.
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GTna M. Fontaine, N6tary Public Ty T
My Commission expires February 10,1995 p4
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