ML20088A929
| ML20088A929 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 04/11/1984 |
| From: | MISSISSIPPI POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20088A928 | List: |
| References | |
| NUDOCS 8404130334 | |
| Download: ML20088A929 (3) | |
Text
-._
EMERGENCY CORE COOLING SYSTEMS l
SURVEILLANCE REQUIREMENTS 4.5.1 ECCS division 1, 2 and 3 shall be demonstrated OPERABLE by:
At least once per 31 days for the LPCS, LPCI and rCS systems:
a.
1.
Verifying by venting at the high point vents that the system piping from the pump. discharge valve to the system isola 6 ion valve is filled with water.
2.
Performance of a CHANNEL FUNCTIONAL TEST of the:
a)
Discharge line " keep filled" pressure alarm instrumentation, and b)
Header delta P instrumentation.
t 3.
Verifing that each valve, manual, power operated or automatic, in the flow path that is not locked, sealed, or otharwise secured in position, is in its cor rect position.
b.
Verifing that, when tested pursuant to Specification 4.0.5, each:
1.
LPCS pump develops a flow of at least 7115 gpm with a total developed head of greater than or equal to g psid 2.
LPCI pump develops a flow of at least 7450 gpa. wit.h a total developed head of greater than or equal to 49 ps.i.d.
125 i
3.
HPCS pump develops a flow of at least 7115 gpm with a total developed head of greater than or equal to 469 psid 445 For the LPCS, LPCI and HPCS systems, at least once per lit months:
c.
1.
Performing a system functional test which includes simulated automatic actuation of the system throughout its emergency operating sequence and verifying that each automatic valve in 4
the flow path actuates to its correct position.
Actual injec-tion of coolant into the reactor vessel may be excluded from this test.
4 2.
Performing a CHANNEL CALIBRATION of the:
a)
Discharge line " keep filled" pressure alarm instrumentation and verifying the:
1)
High pressure setpoint of the:
(a)
LPCS system to be 580 + 20, - O psig.
(b) LPCI subsystems to be 480 + 20, - O psig.
0404130334 840411 oft ADOCK 05000 GRAND GULF-UNIT 1 3/4 5-4
i 3Aow and (EAA clwelepd luaA valanJa. AaA.ue$aan. LG
.c l
3/4.5 EMERGENCY CORE C0OLING SYSTEM ggg e lm #
a de.uy upa'1o wA au nu1.
t i
I j
3/4.5.1 and 3/4.5.2 ECCS - OPERATING and SHUTDOWN i
ECCS division 1 consists of the low pressure core spray system and low r
j pressure coolant injection subsystem "A" of the RHR system and the automatic l
depressurization system (ADS) as actuated by trip system "A".
ECCS division 2 j
consists of low pressure coolant injection subsystems "B" and "C" of the RHR j
system and the automatic depressurization system as actuated by trip system "B".
l
^
The low pressure core spray (LPCS) system is provided to assure that the core is adequately cooled folowing a loss-of-coolant accident and, together with the LPCI system, provides adequate core cooling capacity for all break i
sizes up tu and including the double-ended reactor recirculation line break, t
and for smaller breaks following depressurization by the ADS.
r The LPCS is a primary source of emergency core cooling after the reactor vessel is depressurized and a source for flooding of the core in case of
[
accidental draining.
j The surveillance requirements provide adeauste assurance that the LPCS system will be OPERA 8LE when required.* Although all active components are I:!
testable and full flow can be demonstrated by recirculation through a test j
loop during reactor operation, a complete functional test requires reactor shutdown.
The pump discharge piping is maintained full to prevent water hammar damage to piping and to start cooling at the earliest moment.
l The low pressure coolant injection (LPCI) mode of the RHR system is l
provided to assure that the core is adequately cooled following c loss-of-coolant accident.
The LPCI system, togett ar with the LPCS system, provide adequate core flooding for all break sizes up to and including the double-i ended reactor recirculation line break, anc for small breaks following depressurization by the ADS.
The surveillance requirements provi h ieeusto assurance that the LPCI l
system will be OPERABLE when required. FA' chcugh a'l active components are 1
testable and full flow can be demonstrated by recirculation through a test 199p auring reactor operation, a complete functional test requires reactor shutdown.
The pump discharge piping is maintained full to prevent water hammer damage to piping and to start cooling at the earl-iest moment.
ECCS division 3 consists of the high pressure core spray system.
The high pressure core spray (HPCS) system is provided to assure that the reactor o
core is adequately cooled to limit fuel clad temperature in the event of a j
small break in the reactor coolant system and loss of coolant which does not j
result in rapid depressurization of the reactor vessel.
The HPCS system permits the reactor to be shut down while maintaining sufficient reactor j
vessel water level inventory until the vessel is depressurized.
The NPCS l
system operates over a range of 1160 psid, differential pressure between reactor vessel and HPCS suction source, to 0 psid.
The capacity of the system is selected to provide the required core cooling.
The HPCS pump is designed to deliver greater than or equal to 1440/5010 gpa at differential pressures of 1160/200 psi.
Initially, water from the condensate j
storage tank is used instead of injecting water from the suppression pool i
i GRAND GULF-UNIT 1.
t 3/4 5-1
l....
ne Ma A4 u I
ValurA.ft. msyckca. br l
3/4.5 EMERGENCY CORE COOLING SYSTEM MM#
^ l*' b A#
i
^
cluip Anysttst**A ML ARe$.
l l
ECC5-0PERATING and SHUTDOWN (Continued) l into the reactor, but no credit is taken in the safety analyses for the condensate, storage tank water.
With the HPCS system inoperable, adequate core cooling is assured by the I
OPERASILITY of the redundant and diversified automatic depressurization system and both the LPCS and LPCI systems.
In addition, the reactor core isolation cooling (RCIC) rystem, a system for which no credit is taken in the safety analysis, will automatically provide makeup at reactor operating pressures on a reactor low water level condition.
The NPCS out-of-service period of i
14 days is based on the demonstrated OPERASILITY of redundant and diversified low pressure core cooling systems.
The surveillance requirements provide adequato assurance that the NPCs system will be OPE.uSLE when required, t Although a' I active components are l
testable and full flow can be demonstrated by recirculation through a test loop during reactor operation, a complete functional test with reactor vessel injection requires reactor shutdown.
The pump discharge piping is maintained l
full to prevent wa;er hammer damage and to provide cooling at the earliest soment.
Upon failure of the HPCS system to function properly after a small break loss of-coolant accident, the automatic depressurization system (A05) auto-l matica11y causes solected safety-relief valves to open, depressurizing the i
reactor so that flow from the low pressure core cooling systems can enter the core in time to limit fuel cladding temperature to less than 2200*F.
A05 is j
i conservatively required to be OPERA 8LE whenever reactor vessel pressure exceeds i
135 psig even though low pressure core cooling systems provide adequate core cooling up to 350 psig.
ADS automatically controls-seven. selected safety-relief valves although
%lg r-the safety analysia only takes credit for alves.
It is therefore appro-HP' l
priate to permit one valve to be out-of-servi for up to 14 days without i
materially reducing system reliability.
Q,,, y p,
3/4.5.3 50PPRE5510N P0OL The supression pool is required to be OPERA 8LE as part of the ECC5 to ensure that a sufficient supply of water is available to the NPCs, LPC5 and LPCI systems in the event of a LOCA.
This. limit en suppression pool minimum water volume ensures that sufficient water is available to permit recirculation cooling flow to the core.
The OPERA 51LITY of the suppression pool in OPERATIONAL CONDITIONS 1, 2 or 3 is required by specification 3.8.3.1.
Repair work might require making the suppression pool inoperable.
This specification will permit those repa< rs to be made and at the same time give assurance that the irradiated fuel has an adequate cooling water supply when the suppression pool must be made inoperable, including draining, in OMRATIONAL CONDITION 4.er 5.-
In OPERATIONAL CONDITION 4 and 5 the suppression chamber _ minimum required t
water volume is reduced because the reactor coolant is maintained at er below 200*F.
Since pressure suppression is not required below 212*F, the minimum required water volume is based on NP5H, recirculation volume, and vertaa preven-l tion plus a l'2" safety margin for conservatism.
i GRAND GULF-UNIT 1 8 3/4 5-2
_ _. _, _. _ _ _ _ _. _ _ _ _ _ _ _ _ _ _ _