ML20213G766
| ML20213G766 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 11/13/1986 |
| From: | Lempges T NIAGARA MOHAWK POWER CORP. |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| IEB-86-003, IEB-86-3, NMP-21374, NUDOCS 8611180318 | |
| Download: ML20213G766 (1) | |
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NMP-21374 NlAGARA MOH AWK POWER CORPORATION NIAGARA MOHAWK 300 ERIC BOULEVARD WEST STRAcuSE N Y.13202 vce see maroe November 13, 1986 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555
SUBJECT:
IE Compliance Bulletin 86-03/ Docket 50-220 Gentlemen:
Bulletin 86-03 requested an evaluation as to whether a single failure of minimum i
flow recirculation lines containing air-operated isolation valves could result in a common-cause failure of all emergency core cooling system (ECCS) pumps in a system.
We have reviewed the design and concluded that the design of the minimum recirculation flow valves at Nine Mile Point Unit 1 precludes this type of event.
The Core Spray and Containment Spray Systems are employed at Nine Mile Point Unit 1 to transfer heat from the reactor core and containment following a loss of reactor cool-ant. The minimum flow valves on the core spray system are spring - actuated relief valves, which open when the core spray pump discharge pressure exceeds the spring force.
Each of the two core spray loops has its own minimum flow valve. Therefore, the single i
failure of one relief valve would not render both core spray loops inoperative. The containment spray system does not utilize minimum flow recirculation lines.
- Instead, the system flow path is normally aligned with all manual and remotely-operated valves open so as to initiate flow as soon as the pumps start.
l Therefore, we conclude that Nine Mile Point Unit 1 is not vulnerabic to the type of event described in Bulletin 86-03.
Sincerely, M$
f W
Thomas E. Lempges Vice President Nuclear Generation TEL/amw cc:
Dr. Thomas E. Muricy Regional Administrator d
h f
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