ML20204J290
| ML20204J290 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/25/1986 |
| From: | Murphy W VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| FVY-86-70, NUDOCS 8608110050 | |
| Download: ML20204J290 (2) | |
Text
VERMONT YANKEE NUCLEAR POWER CORPORATION FVY 86-70 R D 5, Box 169. Ferry Road. Brattleboro, VT 05301
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ENGINEERING OFFICE 1671 WJ HCESTER ROAD FRAMINGHAV MASSACHUSETTS 01701 TFLtPHONE 617-872-8100 July 25, 1986 U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Attn:
Harold R Denton, Director Office f Nuclear Reactor Regulation
Reference:
a)
License No. DPR-28 (Docket No. 50-271)
Dear Sir:
Subject:
Primary Containment Leak Rate Testing This letter is written to provide formal notification of the results of the Type A Leak Rate Test performed in accordance with Appendix J to 10CFR50 and Vermont Yankee's corrective action plan, including our schedule for the next Type A test. The summary report of the Type A, B, and C leak rate testing will be provided under separate cover.
In June 1986, Vermont Yankee performed a Type A Integrated Leak Rate Test (ILRT) which had an as-found leakage in excess of the 0.6 wt %/ day allowed by Technical Specifications. The as-found leakage was measured to be 0.78 wt %/ day after 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> of testing.
The cause of the failure was determined to be due to leaks from the following:
1.
drywell head manway cover; 2.
2 vacuum breaker shaft seals; 3.
packing leaks on 5 valves in the atmosphere control system; 4.
2 TIP tubing fittings; and 5.
1 fitting on a torus instrument line.
The leaking penetrations were repaired and after increasing pressure to the t
test pressure, a second Type A ILRT was performed.
The measured leakage during the second test was 0.11 wt %/ day.
From the visual inspections performed, it was determined that the major contributor to the failure was leakage from the drywell head manway. This peretration had not been opened during the outage. Since the manway cover was not removed, the cover bolts were not checked for tightness.
Repair of the peretration consisted of retorcueing the cover bolts. To prevent recurrence, the procedure for installation of the drywell head is being revised to add a step to torque the bolts on the manway cover during installation of the drywell k.
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o VERMONT YANKEE NUCLEAR POWER CORPORATION U.S. Nuclear Regulatory Commission July 25, 1966 Page 2 head.
It will be noted in the procedure that this is to be done even if the cover has not been removed. Although the other leaks were not considered to be major contributors to the test failure, they were also repaired prior to the start of the second Type A ILRT.
Since this is the first Type A test failure since 1978 and since the cause was identified and corrective actions initiated to prevent recurrence, Vermont Yankee does not feel that an increased test frequency is required and will per-form the next test at the interval specified in 10CFR50 Appendix J.
Therefore, based on this requirement, the next test will be performed during the 1989 refueling outage.
Should you require additional clarification or information, please feel free to contact us.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPdRATION fM :?
Warren P.
urphy V Vice President and Manager of Operations
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