ML19322D209
| ML19322D209 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/29/1979 |
| From: | Fairburn G BABCOCK & WILCOX CO. |
| To: | Geoffrey Miller METROPOLITAN EDISON CO. |
| References | |
| TASK-TF, TASK-TMR TMI-79-60, NUDOCS 8002100054 | |
| Download: ML19322D209 (2) | |
Text
a C
s-n v
w
-Babcock &Wilcox
%e, cene,aon c,ou, P.O. Box 1260. Lyncheur& Vs. 24505 Telechone: (804) 384 5111 April 29, 1979 TMI-79-60 Mr. G. P. Miller Station Superintendent Metropolitan Edison Co=pany P. O. Box 480 Middletown, PA 17057
Subject:
Operating Instruction for Sy=pto=s of a Stuck-Open Power Operated Relief Valve Dear Mr. Miller 1.
Introduction Item 3 of I.E. Bulletin No. 79-05 requests utiliries with B&'J supplied NSS syste=s to review the actions required for coping with transients.
This I.E. Bulletin was pro =pted by the nuclear incident at Three Mile Island. During this incident, the Power Operated Relief Valve (PORV) on the pressurizer opened and failed to reclose.
Considerable ti=e passed before the operator determined that the PORV had failed open and took corrective action to isolate the valve. Operating and e=ergency procedut<s ould be reviewed and revised as necessary to mini =ize the potent.1
'or a si=11ar event. To support this effort, infor=ation relative a sy=pto=s of a stuck open PORV is provided below for your consideration.
2.
Design Function of the PORV Overpressure protection of the RCS is provided by two code safety valves on the pressuriter. The ASME code requires that these valves cannot be isolated. Prudent operation of these valves dictates mini = icing the nu=ber of times the code safety. valves will be opened. This is acco=-
plished by providing a PORV with a lower opening setpoint.
3.
Sv=ntons of a Stt.ek Open PORV (see Note (1) below) 1.
RC pressure below the reset pressure of the FORV and decreasing (pri=ary sy=pto=) with:
I. Pressuri:er level increasing or indicatcd high (opposite trend
=ay be possible under certain conditions.)
b.
Pri=ary coolant te=perature approaching saturation.
l 0Ofy g The Babcock l We':Os Company / Est:thshed
s s
h.
V W
Babcock & Wilc0X April 29, 1979 2.
Increase'in the RC d$ain tank' level, pressure, and/or te=perature.
3.
Sustained high (T/C) temperature do.nstream of the PORV.
N012:
(1) The PORV position indicator lights do not provide direct status of the valve position. The light indicates the position of the solenoid operator on the PORV. Therefore, the indicator lights might not indicate a stuck open PORV.
If you have any questions on this operating instruction, please advise.
Very truly yours, B. J. #X G. T. Fairburn Service Manager GTF/fch ec:
R. M. Klinga=an J. F. Hilbish L. L. Lawyer J. L. Seelinger C. R. Montgenery L. C. Rogers S. L. Smith i
a m
--