ML19220B600
| ML19220B600 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/14/1978 |
| From: | Herbein J Metropolitan Edison Co |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| GQL-0404, GQL-404, NUDOCS 7904270079 | |
| Download: ML19220B600 (5) | |
Text
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J/ pm W IO #CA #*CGef32 METROPOLI FAN EDISON COMPANY POST CFFICE BOX 542 READING, PENNSYLVANI A 196C3 TELEPHONE 215 - 929-;6c1
.%_,,, w.h, s-, q GQL Ch0h Director of :Iuclear Reactor Regulation Attn:
Mr. Steven A. Varga, Chief Light '4ater Reactors 3 ranch :Ic. k U. S. :Tuclear Regulatory Cc==issica
'4ashington, D.C.
20555
Dear Sir:
Tnree Mile Island :Iuclear Statien Unit 2 (CC-2)
Cperating License !!c. DPR-73 Docket :Ic. 50-320 Isolation of the Makeup "'ank After a LCCA Attachment i to our letter (CQL Clkk), dated January 26, 1978, described the cperation of the Ep!/ Makeup System at CC-2.
As a result of additicnal staff questions, we have revised the descriptien to ccnfer: to Ocndition C.5 cf Attachment II cf the Unit 's Cperating License.
Inclosed is the revised Attachment i to replace that submitted with our previous letter.
- cerely, a
k J. G. Herbein Vice President-3eneration JGH:JES:c's
Enclosure:
Attachment 1 80 281 x@ o \\
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79042700M
the discharge flow fro: the =rteup pu=ps As reactor coolant pressure decreases,When the reactor pressure has decreased to approxi=r.tely increase.
i d in-the decay heat re= oval pu=ps are capable of providing the re i E U f I
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O ATTACHMENT 1 A.
Sequence of Events Associated with HPI Operation Following a loss of coolant accident (LOCA), the safety features equipment will be automatically actuated by a signal from the Safety Features Actuation System (SFAS). The building isolation valves MU-V2A/3, MU-V376, MU-Vl3, MU-V25 and SC-V377 close, halting all normal system flow out of the reactor building, and nor=al flow into the pressurizer. Normal seal return flow out of the reactor building is stopped while flow into the RC pump seals is continued at a reduced rate. The outlet path is through the seals into the RC system.
The supply of hydrogen to the makeup tank is stopped i==ediately by ES actuated, redundant, safety grade solenoid valves in the hydrogen charging line.
The high preosure injectio, valves MU-V16A/B/C and D in the =ake p lines to the four reactor coolant pump discharge lines open, as do the suction valves DH-V5A/3 in the lines from the Borated Water Storage (SWST) to the =aheup pumps.
An SFAS signal will ensure that only two pumps are operating - one for drawir; suction from the makeup tank (=akeup header) and one from the BUST (EWST header).
One pump is always aligned to the SWST and this pucp will automatically receive an SFAS signal. The system logic assures that there is one (and only one) pump running on the =akeup header in the following manner after an SFAS:
a) If only one pump is running in the =akeup header, that pu=p will continue to run upon receipt of an SEAS signal, b)
If an SFAS signal occurs while two pu=ps (lA 513 or 13 & IC) are running, the 13 pump will be tripped i==ediately.
A time delayed trip signal is supplied to the other running pump in the event that the 13 pumps fails to trip.
c) For either case a) or b) the non-operating pump on the =akeup heaci will re=ain as a standby pu=p and cannot be started while ne other pump is operating. This leckout is acco=plished by a breaker con-tact frc= the non-running pump which is closed in the running pump control circuit thus preventing a false trip of the running pump.
d) Should either MU-P-1A or 1C be taken cut of service, MU-P-13 would be manually valved to the same section of the co==on suction and discharge headers and manually transferred to the same power supply as the out-of-service pump.
Both pumps would be started by an SFAS signal.
In no instance would a single failure prevent either minimum ECCS capability, or allow more than two pumps to run for core than five seconds (one on the makeup header, and one on the 3NST header). During nor=al operation, provision is cade to allow the running of two makeup pumps (lA & 1B or 13 & 1C) on the same bus
.hile drawing suction from the makeup tank.
This operating mode is required for ouma switching te maintain continuous flow to the RC pump seals, and for periodic Lcsting cf the CCCS and makeup pumps themselves. After DH-VSA/S have opened c =-
p'etely, MC-V12 will be closed manually, terminating suction from the makeup tank.80-285