ML18347A545
| ML18347A545 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 11/05/1976 |
| From: | Bixel D Consumers Power Co |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18347A545 (2) | |
Text
-
General Offices: zt2 West Michigan Avenue, Jackson, Michigan 49201
- Area Code 517 788-0550 November 5, l976 Director of Nuclear Reactor Regulation Att:
Mr Albert Schwencer, Chief Operating Reactor Branch No l US Nuclear Regulatory Commission Washington, DC 20555 DOCKET ij~J LICENSE DPR PALISADES PLANT -
REACTOR VESSEL OVERPRESSURIZATION
. ~
~ J [i.;.
. i U
.: _ _/
L!
In our letter dated October 7, l976, responding to your concern regarding.instances of reactor vessel overpressurization, we indicated that we eX:pected to be able to submit short-term solutions for our Palisades Plant about November 1, 1976-This letter presents the short-term measures that have been implemented to minllri.ze po-tential reactor vessel overpressurizations.
- 1.
The operating procedures.have been changed to require that at least one primary coolant pump (PCP) be in operation during plant cooldown until equilibrium (That and Tcold are essentially equal and steam generator secondary pressure is essentially at atmospheric pressure) exists between the steam gen-erators and the remainder of the primary coolant system.
This type of cool down has been *the general op er;.;. ti::; practice at our Palisades Plant.
Formalizing it as a procedural requirement will insure that inadvertent PCP starts cannot lead to overpressurization prob=:_err:s caused by a hot steam.
generator.
- 2.
The operating. procedures have been changed to reg_1 :ire that the high-pressure safety injection pumps (HPSI) be disabled and retu:ned to service at the same time as the safety injection tanks.
This change in procedure will significantly reduce the probability of an.
inadvertent HPSI pump start during the time when the primary system is in the water solid condition.
- 3.
The shutdown cooling system (SCS) was revieweci.
This review showed that the pressure interlock for this system is a permissive type interlock (does not cause automatic valve operation).
This arrange!rrent will insure that during the time when the SCS is in service the primar.r system pressure would be limited to about 3l0 psi, the relief point of the system relief valve. This relief valve has _sufficient capacity ( 142 gpm) to handle the transient tha~a*
could occur through the inadvertent closure of the letdown control,,...,val ire."'\\\\~
- )o~5S *'.
(11 ) ' I '* l ~ :1 [' /**;
(~-. :
~u
j
- ,-:e conclude -01
.-he s_ 1_ ~-rt-changes will significantly reduce the potential for
'" reactor vc;_;:_ _1
_, -*,_,_,_ c.:.~ _ urization.
We are continuing to study this problem with other CE
-:n,~1.-r - ;::..nd 1rill pursue long-term solutions expeditiously.
David A Bixel (Sj,:;ned)
David A Bixel Assistant Nuclear Licensing Administrator CC:
JGKeppler, USN~C
/