ML20198D061
| ML20198D061 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 10/28/1985 |
| From: | Edelman M CLEVELAND ELECTRIC ILLUMINATING CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| (RDC-141(85)), PY-CEI-OIE-0128, PY-CEI-OIE-128, RDC-141(85), NUDOCS 8511120255 | |
| Download: ML20198D061 (2) | |
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h /n 8 THE CLEVELAND ELECTRIC ILLUMIN ATING COMP ANY P O. BOX 5000 - CLEVELAND, OHIO 44101 - TELEPHONE (216) 622-9800 - lLLUMINATING BLDG.
- 55 PUBLICSQUARE Serving The Best Location in the Nation MURRAY R. EDELMAN VICE PRESIDENT NUCU A R October 28, 1985 PY-CEI/OIE 0128 L Mr. James G. Keppler Regional Administrator, Region III Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 RE:
Perry Nuclear Power Plant Docket Nos. 50-440; 50-441 Drywell Vacuum Relief Isolation Valves
[RDC 141(85)]
Dear Mr. Keppler:
This letter is the final report pursuant to 10CFR50.55(e) concern-ing a significant deficiency with the operation of the drywell vacuum relief isolation valves.
This deficiency was reported to Mr. R. Knop of your office by telephone on June 25, 1985, by Mr. B. Walrath of The Cleveland Electric Illuminating Company.
An interim report was sent July 25, 1985, and a progress report was sent August 20, 1985.
This item was evaluated per Deviation Analysis Report 245.
Description of Deficiency FSAR Section 6.2.1.1.3.3.2.5 states that the drywell vacuum relief isolation valves will open following the post-blowdown period after a LOCA when the drywell pressure falls below the containment pressure.
However, the design only allows the vacuum relief isolation valves to open after drywell pressure falls low enough to clear the LOCA signal.
A difference in presture greater than analyzed may develop between the drywell and the containment before the LOCA signal clears or before vacuum relief isolation is manually overridden.
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3 Mr. Jcmes G. Koppler Octobor 28, 1985 PY-CEI/OIE 0128 L Analysis of Safety Implication A difference in pressure between Containment and the Drywell can cause a backflow of water through the suppression pool vents into the drywell.
Since the analysis had assumed an earlier vacuum relief than the design allowed, the post-LOCA backflow velocity and impingement drag loads could be higher than those originally analyzed.
The functional integrity of components affected by the backflow may not be assured.
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j Corrective Action To ensure that' conditions stay within the bounds of the accident analysis described in the FSAR, the control logic to the Drywell Vacuum Relief Valves (IM16-F010A/B) was revised.
An Engineering Change Notice was issued to provide automatic opening of the valves when the Drywell Pressure falls below Containment Pressure following the post-blowdown period after a LOCA.
This deficiency will be resolved for Unit I when the design change is implemented.
Modifications required for Unit 2 will be implemented consistent with the Unit 2 construction schedule.
f Please call if there are any questions.
Sincerely, h
3 Murray R. Edelman Vice President Nuclear Group MRE:sab cc:
Mr. J. A. Grobe USNRC, Site Office (SBB50)
Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
29555 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 29555 Records Center, SEE-IN Institute of Nuclear Power Operations 1190 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339
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