ML20214C360
| ML20214C360 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/12/1986 |
| From: | Williams J TOLEDO EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 1317, IEB-86-003, IEB-86-3, NUDOCS 8611210077 | |
| Download: ML20214C360 (3) | |
Text
)f))
TOLEDO
%m EDISON JOE VVILUAMS JR.
s,m,v, #.s w S o,
14191249 2300 Docket No. 50-346 L4'91243*223 License No. NPF-3 Serial No. 1317 November 12, 1986 Mr. James G. Keppler, Regional Administrator United States Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137
Dear Mr. Keppler:
This letter is submitted in response to IE Bulletin 86-03: Potential Failure of Multiple ECCS Pumps Due to Single Failure of Air-Operated Valve in Minimum Flow Recirculation Line (Log No. 1-1477). The bulletin was written as a result of a design deficiency identified in four cases which involved the minimum recirculation flow paths for pumps in the Emergency Core Cooling System (ECCS).
The specific concern involves a postulated small break LOCA which initiates an ECCS actuation signal that starts the ECCS pumps. During a small break LOCA, RCS pressure may not readily decrease below the ECCS pump shutoff head. A single failure resulting in the loss of the minimum flow path concurrent with E"CS pump actuation would cause the pumps to operate deadheaded until RCS pressure decays below the ECCS pump shutoff head. Operating the pumps deadheaded could result in pump damage and failure within a few minutes.
Toledo Edison has reviewed the ECCS pump / recirculation path design at the Davis-Besse Nuclear Power Station Unit No. 1.
The scope of the review included the high pressure injection (HPI) and low pressure injection (LPI) systems. With regard to the concerns presented in this bulletin, the review identified that:
A.
A separate minimum flow recirculation line is provided for each HPI pump. These lines route flow back to the borated water storage tank through several locked open valves.
B.
For each LPI pump, a separate minimum flow recirculation line routes flow from downstream of the coolers back to the LPI pump suction. One locked open manual valve is provided on each recirculation line.
)
g 8611210077 861112 PDR ADOCK 05000346 G
PDR (l
THE TOLEDO EDISON COMPANY E060N PLAZA 300 MAD! SON AVENUE TOLEDO. OHIO 43Gb2 I \\
)
e a
D:ckat No. 50-346 License No. NPF-3 Serial No. 1317 November 12, 1986 Page 2 Based on our review, no single failure on an ECCS minimum flow recirculation line could cause an ECCS pump to operate deadheaded. A separate minimum flow recirculation flow path is available for each pump should the RCS pressure exceed the pump shutoff head.
In addition, no common recirculation header is provided such that a single failure could impact redundant ECCS pump trains. Based on this review the safety concern identified in IE Bulletin 86-03 is not a problem at Davis-Besse Nuclear Power Station Unit No. 1.
Very truly yours,
.l(}tCtdrny
- 1' 7'
([)
JW:WD:dem cc: DB-1 NRC Resident Inspector NRC Document Control Desk
. a.
Dsckat No. 50-346 License No. NPF-3 Serial No. 1317 November 12, 1986 Page 3 ATOMIC ENERGY ACT OF 1954 SECTION 182a SUBMITTAL IN RESPONSE FOR THE DAVIS-BESSE NUCLEAR POWER STATION UNIT NO. 1 FACILITY OPERATING LICENSE NPF-3 i
This letter is submitted in conformance with Atomic Energy Act of 1954 Section 182a in response to IE Bulletin 86-03 (Log No. 1-1477). This letter addresses potential failure of multiple ECCS pumps due to a single failure of an air operated valve in a minimum flow recirculation line.
i i
By
/ --
T.J.[/LicensingDirector yfra l
Nuclea i
For J. Williams, Jr.
Senior Vice President, Nuclear t
i i.
4 i
i Sworn to and subscribed before me this 12th day of November, 1986.
i OM(
l U
N Notary Public, State of Ohio l
Mycommissibnexpires5/18/91.
.