ML19305B286
| ML19305B286 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 03/05/1980 |
| From: | Kalivianakis N COMMONWEALTH EDISON CO. |
| To: | Case E Office of Nuclear Reactor Regulation |
| References | |
| NJK-80-85, NUDOCS 8003190457 | |
| Download: ML19305B286 (3) | |
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Commonw:alth Edison
. af Quad Citiss Nuclear Power Station -
- ((
22710 206 Avenue North e:
Corcova, Illinois 61242 Telephone 309/654-2241 NJK-80-55 March 5, 1980 Mr.-Edson G. Case, Deputy Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission
. Washington, D.C.
20555
Dear Mr. Case:
Enclosed please find a listing of those changes, tests, and experimer.ts completed during the month of February 1980, for quad-Cities Station Units I and 2, DPR-29 and DPR-30. A summary of the safety evaluation is being reported in compliance with 10 CFR 50 59 Thirty-nine copies are provided for your use.
Very truly yours, COMMONWEALTH EDISON COMPANY
. QUAD-CITIES NUCLEAR POWER STATION N. J. Kalivianakis
-Station Superintendent 3
NJK/BB/ san Enclosure cc:
R. F. Janecek 80031s0($]
r
n.
D H-4-1 s 2-78-37 Pressure Suppression Chamber-Ring Girder Drain Slot Enlargement Description of Modification These modifications enlarged the drain slots on the botton of the pressure suppression chamber ring girders.
The larger drain holes are intended to increase complete draining capabilitics of the suppression chamber by eliminating the blockege which occurs when using the small drain slots.
Summary of Safety Evaluation The increased drain hold size does not reduce the stiffener section properties below the minimum design requirements, therefore the probability of an occurrence or consequence of an accident previously evaluated in the FSAR has not been increased. And since the suppression chamber stiffeners are passive structural components, the possibility for an accident of a different type than previously evaluated in the FSAR is not created.
M-4-1-77-36 Drywell Mechaalcal Snubber Description of Modification This modification involved replacement of the hydraulic snubbers in the drywell with mechanical type. The mechanical snubbers were obtained from Pacific Scientific and are of the same rating at the nydraull-units they replaced. This modification was installed because the n.achanical snubbers are more reliable than the hydraulle type due to the elimination of relatively radiation-sensitive components such as hydraulic fluids and seals ani the non-leaking character of the mechanical type.
i Summary of Safety Evaluation The design function of the af fected systems will not be altered.
The performance characteristics of the snubbers will not be altered since the mechanical and hydraulic snubbers are of the same ratings.
- However, the mechanical snubbers will provide greater reliability because the consideration of hydraulic fluid degradation and leakage does not exist.
No design basis margin of safety as defined in the Technical Specifications
.is affected by this modification.
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,a it-4-2-78-12 Recirculation Pump Suction Valves Description of Modification This modification removed the LPCI loop selection closure of the recirculation system suction valves (M0 2-202-4A & B).
Both valves will now remain in the open position in case of a line break between the recirculation suction and discharge valves thus allowing the reactor to depressurize.
This modification was installed to prevent a situation where inventory in the vessel is decreased while system pressure remains high during a recirculation line break.
Summary of Safety Evaluation The probability of sn occurrence or the consequence of an accident as previously evaluated in the FSAR is not increased because maintaining both recirculation suction valves in the open position decreases chances of vessel pressure buildup in case of a water line break.
flo new accident or malfunction is created.
The modified valves will be surveillance tested as before and the margin of safety is unaffected.
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