ML20028A119
| ML20028A119 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 10/27/1982 |
| From: | Conn W BURNS & ROE CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| REF-PT21-82-721-000 BRGO-RO-82-011, BRGO-RO-82-11, PT-82-721, PT21-82-721, PT21-82-721-000, NUDOCS 8211160443 | |
| Download: ML20028A119 (5) | |
Text
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Subject:
Work Order 3900-4000 V
Washington Public Power Supply System WNP-2 10CFR2? 'leportable Condition #82-11 RHR Relief Valve Vent Responds to:
NA October 27, 1982 BRGO-RO-82 011 Response Required:
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i U.S. Nuclear Regulatory Commisssion Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94956 g
Attention:
Mr. R.H. Engelken Gentlemen:
This letter is to report to you a condition we have deemed reportable under 10CFR21. This was discussed with John Elin of your staff on October 22, 1982.
The concern is that given the single failure of an iso-lation valve post-LOCA, we have a direct path for fission products to go from the wetwell to the reactor building, bypassing contain-ment. This results in a leakage rate which is unacceptably high.
Complete details are contained in the attached evaluation.
If you have any questions, please contact A.T. Luksic at (509) 943-8243.
Very truly yours, W.G. Conn Senior Group Supervisor WGC:ATL:lvs Attachment cc:
B. A. Holmberg, SS w/a T.G. Tellefs.on, SS w/a R.T. Johnson, SS w/a L.C. Floyd, SS w/a i
E. LeBlanc, Bechtelw/a R.M. Nelson, SS w/a
/f C211160443. 821027
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PDR ADOCK 05000397
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RHR Relief Valve Vent (82-11)
Description of Defect There are four (4) RHR reliuf valves which have a 2" 9 vent hole on the valve body. The valves are RHR-V-55A RHR-V-95A, RHR-V-55B and RHR-V-95B.
These valves are situated such that the failure of a single motor operated valve, RCIC-V-113, would allow an open leakage path from the wetwell (primary contain-ment) directly to the reactor building (secondary containment).
The attached sketch illustrates the situation. Containment penetration X-116 is an open path into the wetwell's gaseous volume.
In the steam condensing mode, RHR-V-55A (or B) and RHR-V-95A (or B) protect the RHR heat exchnager from over-pressurization.
In order to accommodate condensation in the line between these valves and containment, a vacuum breaker has been installed. That consists of penetrat>an X-116, RCIC-V-ll3, RHR-V-102, RHR-V-101A (or B), RHR-V-103A (or B),
and RHR-V-179A (or B).
All of these valves are normally open. Upon a containment isolation signal, the only valve to close would be RCIC-V-113.
If it failed to close, and a LOCA had occured, the wetwell would pressurize, and the wetwell atmosphere would vent down this path. Details of the RHR relief valves show that a flow path exists which would allow the wetwell atmosphere to vent directly to secondary containment.
Date and Method of Discovery The potential deficiency was noted during a review of a Request For Information (RFI-C0500-M-00740) at the WNP-2 site on 9/15/1982.
Analysis of Safety Significance 4
B&Rhasestimatedthegaseousreleasefromthesefourpathsatj.2x10 scfm during the first 450 see after a LOCA and at a rate of 4.9 x 10 scfm thereaftcr.
This can be compared to the allowable release rate for primary containment of approximately 1.7 scfm.
Corrective Action Proposed The manufacturer (Crosby Valve & Gage Co.) has indicated that the valve can be converted to incorporate a bellows seal which would alleviate this problem.
However, this may not be schedular responsive and other options are also being evaluated.
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J 26 Log Sheet N2, l
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PART 21 REPORT LOG SHEET I
1.
Subject of Report -
RHR RELIEF VALVE VENT 2.
Date Verbal Notification Received - OCTOBER 22,1982 Received By John Elin 3.
Date Infonnation Placed in Daily Report - OCTOBER 24, 1982 4.
Name and Address of Person Providing Verbal Notification a) Name -
ROGER JOHNSON b) Company and Address - BURNS & ROE. INC.
601 Williams B?vd., Richland, Washington 99352 f
c) Telephone No. - (509) 943-8200 1
(
5.
Description of Problem -
Given the single failure of an isolation valve post-LOCA, there is a direct path for fission products to go from the wetwell to the reactor building, bypassing containment.
6.
Nuclear Facilities Affected -
WNP-2 (DN 50-397)
~7 Date 5-day Written Report Due -
10/27/82 Date Received - 10/29/82 8.
Mail' Written Report to HQ's and Other Affected Regions a) Date Mailed to HQ's' (Bill Mills) -
11/02/82 b) Date ~ Mailed' to Other Regions -
Regions Mailed To -
9.
Give Written Report to Each Region V Affected Principal Inspector a) Date Given to Principal Inspector (s) -
John Elin b) Name(s) of Inspectors Given To -
10.
Additional Comments -
1