ML20028G962
| ML20028G962 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 09/24/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20028G961 | List: |
| References | |
| NUDOCS 9010040307 | |
| Download: ML20028G962 (10) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 70 TO FACILITY OPERATING LICENSE NO. NPF-29 ENTERGY CPERATIONS. INC.
GRAND GULF NUCLEAR STATION, UNIT 1 DCCKET NO. 50-416 1.0 -INTRODUCTION
.By letter dated April 27, 1990, as revised July 5,1990, % gust 6,1990 August 9, 1990, August 20, 1990, and September 11, 1990, the licensee (System Energy Resources, Inc., before June 6, 1990, and Entergy Operations, Inc., on or after June 6,1990), requested an amendment to Facility Operating License No. NPF-29 for the Granc' ' M Nuclear St' tion, Unit 1.
The licensee's revised applications provid d e Mitional information regarding implementation of the proposed amendment td #J not significantly alter the action previously noticed or l'!2ct the description-of the action published in the Federal Register on July 25, 1990 (55FR30296).
The proposed amendment would revise the Grand Gui Nuclear Station, Unit 1 (GGNS-1) Technical Specifications-(TS) and' Bases by adding requirements foi the operation and use of the alternate decay heat removal system (ADHRS) during future GGNS-1 outages.- In addition, the amendment would require-automatic isolation of the reactor vessel and automt. tic injection of water into the-reactor by one of the two emergency core cooling system (ECCS) subsystems required to b? operable during Operational Condition (OC)4(coldshutdown)andOC5(refueling)tomitigateinadvertent-reactor vessel drainage.
The changes which would be effected by_ the proposed TSs, are as follows:
TS 3/4.3.2 Isolation Actuation -Instrumentation Table 3.3.2-1 is revised-to require the operability of the reactor vessel 1cw water level (Level 3) trip function to isolate RHR system isolation valves E12-F008.and E12-F009 during Operational Conditions (OCs) 4 and 5..
Note (p) -is added to. allow one trip system and/or isolation valve to be 4
inoperable for.14 days, provided the diesel generator associated with the b
operable isolation valve is operable. Also, Action 31 is added to specify the measures to be taken if the trip function or the isolation valves becore 'noperable during OCs 4 and 5.
Table 4.3.2.1 1 is revised to require sm veillance testin9 of the reactor vessel low water level
~ i.% system isolation trip function in OCs 4-and 5.
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~2-TS 3/4.4.9.2' Reactor Coolant System - Cold Shutdown
-T e L m t ng condition for Operation (LCO) of TS 3.4.9.2 is revised to h
iii specify that one of the two required RHR system shutdown-cooling mode loops shall have an operable associated diesel generator.
In addition, TS notations applicable only for RF03 are deleted.
TS3/4.5.2EmergencyCoreCoolingSystems(ECCS)-Shutdown l
The LCO of TS 3.5.2 is revised by deleting the provision which allows manual realignment for the three LPCI subsystems and adding a note ta the o
LCO which. allows only one of the two required ECCS subsystems or syst)ms to be manually realigned. Action "a." is modified to specify that 3
operations that have a potential for draining the reactor vessel be.
suspended if the automatic ECCS subsystem / system required by the LCO is L
In addition, TS notations applicable only for RF03 are deleted.'
TS 3/4.6.4 Containment Systems - Containment and Drywell Isolation Valves
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The Action of TS 3.6.4 is revised to provide remedial measures if the required automatic isolation valves, E12-F008 and E12-Fn09. become inoperable in OCs 4 and 5.
In addition TS notations aplicable only for RF03 are deleted.
TS 3/4.9.11.1 Refueling Operations - Residual Heat Reaval and Coolant Circulation, High Water Level
- The LCO and Surveillance Requirements (SR) of TS 3/4.9.11.1 are revised to recognits the.ADHRS reactor cooling mode in operation as an acceptable substitute for the.previously required RHR shutdown cooling mode train being in operation provided one RHR shutdown cooling mode train and its associated diesel generator are operable.
In addition, TS notations l_
applicable only-for RF03 are deleted.
TS 3/4.9.11.2 Refueling Operations -. Residual Heat Removal and Coolant' Circulation, Low Water Level The'LCO and SR of TS 3/4.9.11.2 are revised to recognize the ADHRS reactor cooling mode as an acceptable third shutdown cooling mode in addition to
- the two RHR shutdown cooling mode trains.. A footnote is added specifying that one of the two required shutdown cooling modes must have an operable-
-t associated diesel generator. ~ Action a. is revised to require that if the action cannot be taken, either water level must be raised to the high level,.or all' operations involving an increase in the reactor decay heat load must be suspended and action to establish Secondary Containment Integrity within one hour be initiated.
In addition, TS notations applicable only for RF03 are deleted.
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Bases 3/4.5.2 ECCS - Shutdown A paragraph is added to reflect _ changes in TS 3/4.5.2 and state that the one ECCS subsystem or system requiring manual realignment shall be capable of being realigned from the control room panels within 20 minutes.
Another paragraph is added prohibiting LPCI line "C" from simultaneous operation with ADHRS.
Bases 3/4.9.11 Residual Heat.... oval and Coolant Circulation A paragraph is added stating that an operable RHR system shutdown cooling mode train includes an operable RHR pump and an operable RHR heat exchanger.
Another paragnph :s added describing the ADHRS purpose, its acceptability as another shuMown cooling system during Refueling (OC 5), additional requirements inposed to compensate for its not being safety related and not being capat.le of being powered by a' diesel generator, and defining an l-operable ADHRS as having two operable ADHRS-pumps'and two operable ADHRS-heat exchangers.
A third paragraph is added to caution that simultaneous operation of the ADHRS reactor cooling mode an; RHR system shutdown cooling mode trains "A" and "B" are pnhibited for certain alignments in OC 5.
2.0 EVALUATION-The alternate decay heat removal system (ADHRS) was designed and built to supplement the residual heat removal (RHR) system shutdown cooling mode during Operational Condition (OC) 4. " Cold Shutdown," and OC 5,
" Refueling." During each refueling outage, one or both of the RHR shutdown cooling mode loops are removed from service to perform maintenance or-by the-NRC for one-time use during the third refueling outige (RF03)pprove surveillance on the loops or on supporting' systems. 'The ADHRS was a contingent-upon the licensee's commitment to implement administrative i
Technical Specifications (TS)y requirements of the ADHRS in lieu of controls to define operabilit o'
.. The licensee also connitted to implement
-f administrative controis in lieu of TS for the automatic isolation of 'he reactor vessel, and the automatic injection of water into the reactor p
vessel in the event of inadvertent drainage of reactor coolant from the vessel. For the ~1ong term use of the ADHRS, in subsequent outages, the-i licensee committed to propose TS changes. The submittals identified in
-Section 1.0, provide the licensee's proposed TS changes and administrative controls for use of the ADHRS, automatic isolation of the reactor vessel, and automatic injection of water into the vessel.
The NRC staff's evaluation of the ADHRS design and one-time use in RF03 was reported in its Safety Evaluation supporting Amendment No. 59 to the Facility Operating License issued on March 27, 1989. The staff's evaluation of the TS and administrative controls for equipment needed toz
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b mitigate a'draindown event were reported in its Safety Evaluation i
supporting Amendment No. 58 to the Facility Operating License issued on March 16, 1989. This evaluation determines whether the TS and-administrative controls, proposed for long term use of the ADHRS, meet the' i
comitments and, resolve staff concerns identified in the March 16, and o
b March 27, 1989 Safety Evaluations.- The. administrative controls, proposed I
for long term ADHRS use, are the same as those approved by the staff for one-time use in'RF03, except for those superseded by the proposed TS changes.
2.1 Administrative Controls The ADHRS is not a safety-related system and cannot be powered by an emergency diesel generator. The system has two pumps and two heat p^
exchangers. Decay heat transported from the reactor fuel is transferred to plant service water in the two heat exchangers. The ADHRS can take suction'from the reactor, the spent fuel pool or the suppression pool; however,theflowpathforshutdowncoolingofthefuelinthereactnr (called ADHRS reactor cooling mode in the proposed TS). takes suction -
through the RHR common suction line and discharges through the LPCI line "C."'
The ADHRS is designed to be used only during cold shutdown (OC 4) and u
refueling (0C5).
Heat removal capability is designed to maintain average reactor coolant temperature less than the DC 4.TS limit (200"F) at one day
-after shutdown and less than the OC 5 TS liinit-(140"F) at seven days after b.
shutdown. The ADHRS can be operated from the control room. System flow can be varied from 1000 gpm to 3600 gpm.
Reactor coolant temperature is monitored at the inlet and outlet of the heat exchangers. A radiation monitor. in the plant service water line is included in.the present TS.
The licensee'has incorporated the ADHRS in the Updated Final Safety Analysis Report as another system designed for shutdown cooling. In addition,theRHRSystemOperatingInstruction(501)andtheOff-Normal Event Procedure (ONEP) 05-1-01-III-1 have been revised to incorporate-the as loss of decay heat-removal)g procedures, off normal procedures (such i
use of ADHRS into its.operatin L
.-and restrictions and administrative controls. These procedures prohibit the use of ADHRS in OC 1 " Power Operation," OC 2 "Startup," and OC 3 " Hot Shutdown."
In addition, these procedures require tnat the valves which isolate the ADHRS from connected b
plant-systems during these Operational Conditioas be either locked closed 0
or deenergized. The procedures require the ADHRS to be stopped and:
manually isolated if loss of shutdown cooling occurs during 00 4 when the reactor. vessel head is on to prevent over pressurization of the ADHRS.
Potentially adverse effects due to simultaneous operation of the ADHRS and certain alignments' of. the RHR System shutdown cooling mode trains "A" and."B," and simultaneous operation of the ADHRS and LPCI subsystem "C" are prohibited. Manually-aligned ECCS subsystems must be capable of being properly aligned with pumps running and injecting water into the reactor i:
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x vessel within 20 minutes to be considered operable. Some of these u
administrative controls are included in the proposed TS Bases.. The staff concludes-that adm111strative controls for pot 4ntially adverse system interactions have baen adequately addressed by dhe licensee.-
One staff concern W be resolved for long-term ADHRS use, identified in its previous Safety Evaluations dated March 16 and March 27, 1989, was
. resolved by the l'.censee's submittals. The jockey pumps which keep the discharge lines of LPCI lines "A," "B," and "C" full of water must be L
turned off when the ADHRS is in operation. Turning the jockey pumps off L
is necessary when operating ADHRS because a valve upstream of the suction I
to the jockey pumps must be' closed.
In its submittals, the licensee stated L
that during RF03 operation of'the ADHRS, the keep-fill line pressure alarms did not actuate for LPCI "A" or "B", discharge lines.
However, if.
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LPCI "A" or "B" did become inoperable for this reason during ADHRS l_
operation, the Operations Annunciator Res)onse Instruction adequately addresses actions to be taken. Turning tie LPCI "C" jockey pump off was a concern because it is designed to. keep the reference leg filled with water for one division of suppression pool water level instrumentation.
s Based e t review of the design and operational characteristics of the n
ADHRS, the licensee has determined that the ADHRS, while operating, r
produces sufficient pressure to keep the reference _ leg of the water level instrumentation filled with water. The licensee concluded, and the staff agrees, that'this concern has been resolved.
The licensee has committed to include calculated thermal performance of the ADHRS as a function of time after reactor shutdown ir administrative procedures that control the use of ADHRS.to assure that its use will be within design heat removal capability. The ADHRS will not be used unless o
prior performance calculations indicate the TS limitation e average reactor water temperature will be met.. In addition, when the ADHRS is used for new conditions, the performance will be demonstrated by recording u
relevant thermal and hydraulic parameters. -
The ADHRS-heat cxchangers l
l-should be included in the-periodic performance testing rec'Aunended in Generic-Letter 89-13 " Service Water System Problems Affe', ting Safety-Related Equipment." For long-term usage, plant service water may cause fouling-of the tubes and tubes may need to be plugged if they leak.:
2.2 RHR' System Shutdown Cooling Mode Train
-In its submittals, tLe licensee stated that "RHR system shutdown cooling 1
' mode train" as used in TS 3.4.9.2, TS 3.9.11.1 and TS 3.9.11'.2 identifies -
4 two flow-paths for return of reacto: coolant to the reactor vessel;
= (1) through the feedwater spargers ' or (2) through the LPCI lines. This Y,_
is a charge in the normal flow path used for shutdown cooling and would:
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allow greater flexibility in' scheduling maintenance work during the outage. The Updated Final Safety Analysis Report (UFSAR) was revised in
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1989 based on a 10 CFR 50.59 safety analysis to reflect this changed i
definition of RHR' system shutdown cooling rade train.. The staff has reviewed the bases for this change in the coolant return flow path and the q
licensee's analyses to justify it.
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'The licensee's 10 CFR 50.59 analysis addressed the mechanical. design of.the
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LPCI nozzles, flow deflectors, and thermal shields for limited usage of the
'LPCI injection line for shutdown cooling. A total of 60 cycles of 15-minutes duration in OC4 and 60 cycles of 14 days duration in 005 was analyzed and found to have usage factors below design allowables and j
-stresses below ASME Code limits. Other submittals state that admin-istrative controls are required in 005 to prevent removal of fuel assemblies near the injection outlet 50 as to prevent mechanical damage to incore instrumentation and control rods. However, reactor coo; ant circula'. ion and mixing were not addressed.
The lir.ensee was requested to provide an evaluation of the.adequag of returning reactor coolant via the LPCI injection line versus retura flow via=the feedwater sparger, with respect to effective coolant circulation and temperature monitoring. The licensee provided an evaluation by letter dated August 9, 1.?0. The evaluation demonstrated that the return.
of coolant via' the LPCI injection line by either RHR or by ADHRS during Ji OCs 4 and 5 is acceptable for maintainirg coolant circulation, mixing, heat removal, and temperature monitoring and control. The staff' agrees with this conclusion.
L The staff concludes that_ coolant return paths through LPCI injection lines are acceptable when using the RHR for shutdown cooling ir DC 4 or OC5. As provided'in the licensee's administrative controls, ussge of these L
flow paths is limited to that analyzed in the 10 CFR 50.59 analysis, and these flow paths are not used during re:novk1 of fuel assemblies near injection line outlets.
'2.3' Changes to Technical Specifications The. licensee has proposed changes to the TS and Bases to implement 7
limiting conditions for operation and surveillance requirements for: (1) i long-term tse of; thel ADHRS and RHR system in shutdown cooling,- and (2) ~
automatic isolation of the reactor and injection of water using. an ECCS pump in an inadvertent draindown of reactor water. These changes are addressed. separately below, m
2.3.1 ShutdownCoolingRequirements(TS 3/4.4.9.2, 15 3/4.9.11.1, TS 3/4.9.11.2 and TS Bases 3/4.9.11) 4 IThe-ADHRS can only be powered by offsite. power and uses plant service l water. Thus, the ADHRS is more vulnerable to loss of heat removal l
capability than an-RHR shutdown cooling mode loop.
In addition, the present TS do not require on-site emergency. diesel generator power for an operable RHR shutdown cooling mode loop or train.
For one-time usage of-s
'ADHRS in RF03, the licensee proposed administrative requirements, which
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the staff approved. The approved requirements were:
1.
For T5 3.4.9.2 which is applicable to the cold shutdown reactor condition"(OC4)and-TS3.9.11'.2whichisapplicable'totherefueling condition?(OC5witha~lowwaterlevel),twoshutdowncoolingsystems were required - one operable and one operating. Additional requirements were:
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a.
One of the two required systems shall be capable of being
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powered by an onsii.e diesel generator.
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b.
To provide for loss of the operating system, the operable system shall be capable et being placed in service in accordance with rel'vant TS Action Statements, c.
To provide for loss-of the o>erating system and loss of offsite
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power, an ECCS system shall ae operable and capable of being powered by en onsite diesel generator.
2.
For TS 3.9.11.1, which is applicable to the refueling condition (0C5
-with a high water level), one 9perating shutdown cooling system is required. To provide for loss of offsite power, if the required system is not capable of being powered by an onsite diesel generator (e.g.,theADHRS),anRHRsystemanditsassociatedonsitediesel 7,
generator shall be operable..
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The proposed TS changes meet these requirements. The limiting conditions foroperation(LCOs)ofTS3/4.4.9.E.TS3/4.9.11.1,andTS3/4.9.11.2 L
would be modified to require at least one~RHR system shutdown cooling mode-L triin and its associated diesel generator to be operable.
In addition,
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l t'ie LCOs, TS 3/4.9.11.1, and TS 3/4.9.11.2 would be changed to include the ADHRS-as an acceptable system for shutdown cooling. An operable ADHRS would'be defir.ad in the Bases to h Bases 3/4.9.11 as having tvo pumps and two heat exchangers, taking suction from tire reactor coolant.
"B" recirculation' loop and discharging through the LPCI "C" line to the reactor.
'A new requirement would be added to Action "a." of TS 3/4.9.11.2(0C.5 with low water level).to require raising the water level to the high water level of-TS 3/4.9.11.1 if the Action requirements cannot be met.
This would result in placing the plant in a safer configuration because only one shutdown cooling system is required with a high water level-versus two required with a. low water level.
The. Surveillance Reouirement (SR) 4.9.11'.1 and SR 4.9.11.2 would be changed to include the ADHRS. This surveillance requires verification at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />'that the. shutdown cooling system required'to be operating is circulating reactor coolant.
In addition, the notes to the LCO ':ound be changed to include the ADHRS. The notes permit.the removal of the' shutdown cooling pump from operation for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per an-8 hour period.-
3 The staff concludes th'at with the proposed TS changes and administrative.
l controls described in Sections 2.1 and 2.2, the use of the ADHRS for j
1 shutdown cooling meets or exceeds. administrative requirementsiproposed by i
t the licer.see, and. approved by the staff in its Safety Evaluation dated March 27, 1989. The staff further concludes that the proposed TS meet or exceed the % vel of safety in current TS for shutdown cooling.
Accordingly,Lthe proposed changes for TS 3/4.4.9.2 TS 3/4.9.11.1,
-TS 3/4.9.11.2 and TS Ptses 3/4.9.11, are acceptable.
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u 8-2.2.2 Draindrown Event Requirements (TS 3/4.3.2. TS 3/4.5.2, TS 3/4.6.4 and
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T5 Bases 3/4.5.2)
The pres nt TS for ECCS in OC 4 and for reactor vessel isolation in OC 4=
oual actuation of ECCS and manual reactor vessel isola-and OC 5 tion fc-uon of a.draindown event.
For one-time usage of an exception to TS 3.0.4 in RF03 to allow draindown
- of the water level during refueling (OC 5) while using the ADHRS for shutdown cooling, the licensee proposed, and the staff approved, administrative controls for automatic ECCS initiation and water injection.
In addition, the licensee proposed, and the staff approved, administrative controls for requiring operable isolation valves in the J
RHR common mode suction level (E12-F008 and E12-F009), and operable i
isolation actuation instrumentation (RHR system isolation on reactor-vessellowwaterlevel-Level 3). The approved requirements were:
1.
For TS; 3.5.2, which is applicable to cold shutdown (OC 4), at least one ECCS subsystem or system was required to be capable of automatic i
l initiation and water injection.
2.
For TS 3.3.? and T: 3.6.'4, et least one of the isolation-valves and associated isolation actuation instrumentation was required to be operable during OC 4.and OC 5.
1 The proposed changes to TS 3.5.2 meet or exceed these requirements. The.
LCO of TS 3.5.2 would be revised to delete the provision for manual alignment of the three LPCI subsystems, and to allow manual alignment of only one.of the two required ECCS subsystems or systems.
In addition,-the LCO would require one of the two required ECCS subsystems or f.ystems to p
have:an operable associated diesel generator. Action "a." of TS 3.5.2
- would be revised to require suspension of. operations'having a potential to drain the; reactor vessel in the event the autom tic ECCS subsystem or j
system.is inoperable. The Bases for TS 3.5.2 would be revised to state-that an'operaole manually-aligned ECCS subsystem or system must be capable cf being aligned within 20 minutes. This time-interval.is based on.the. licensee's analysis of a draindown event. The Bases for TS 3.5.2 would also prohibit LPCI "C" ECCS subsystem from simultaneous operation with the ADHR,...
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The proposed changes to.TS 3/4.3.2 and TS 3/4.6~.4 meet or exceed the l-previously approved requirements. Operability and surveillance of both L.
- RHR' system isolation valves and both trip systems of the RHR system i
isolation instrumentation-(Level 3 of the' Reactor vessel: water level-instrumentation),wouldberequiredinOC4andOC'5.~Anaddednotewould ml'
- allow one valve and/or trip system to be inoperable for 14 days provided the diesel generator' associated with the operable isolation valve is
. operable. An added Action statement for an inoperabic instrumentation channel would require the. isolation valve to be closed, if,the lin? !s-l t
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not' needed for shutdown cooling, or to establish secondary containment integrity. A footnote would be added to the Action statement of TS 3.6.4 to require use of the Action statement of TS 3.3.2 if one of the isolation valves becomes inoperable.
The staff concludes that with the administrative controls described in Sections 2.1 and 2.2, the proposed changes for TS 3/4.3.2, TS 3/4.5.2, e~~
TS 3/4.6.4, and TS Bases 3/4.5.2 meet or exceed the administrative requirements proposed by the licensee, and approved by the staff-in its Safety Evaluations dated March 16 and March 27, 1989.. The staff further concludes that the proposed TS meet or exceed the level of safety in current TS for an inadvertent draindown event. Accordingly, the proposed changes to these TS and TS. Bases are acceptable.
~2.4 Summary The staff concludes that the proposed TS-changes meet or exceed the administrative requirements implemented by the licensee for one-time use o
of the ADHRS during the third refueling outage and approved by the staff l'
in its Safety Evaluations dated March-16 and March 27, 1989. The staff t
further concluc'es that technical concerns raised in the previous review-regarding the design and use of the ADHRS have aeen resolved by the L
submittals. The licensee bss committed to incorporate administrative-i controls into procedures to assure the use of ADHRS will be within design
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heat removal. capability..
3.0- ENVIRONMENTAL CONSIDERATION This amendment-involves a change in a requirement with respect to the installation or use of a facility component located within the restricted area as defined-in 10 CFR Part 20 and changes the surveillance
. requirements. The staff has determined that the amendment involves no significant increase in the amounts,-and n_o significant change in-the.
4 types, of:any effluents that may be released off site. and that there is_
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no significant increase in individual or cumulative occupational radiation exposure. The Commission has-previously issued a proposed finding that this amendment involves no significant hazards consideration, and there has been no public comment on such finding.. Accordingly, this' amendment meets the eligibility criteria for categorical exclusion ~ set forth in 10CFR51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection'with the issuance of this amendment.
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4.0 CONCLUSION
The Comission made a propoced determination that this amendment-involves no significant hazards consi,1eration, which was published in the Federal-Register on July 25, 1990 (55 F2 30296), and consulted with-the State of Mississippi', No public comments or. requests for hearing were received,-
and the State of Mississppi did not have any comments.
The staff has concluded, based on the considerations discu. sed above,f the-that:
? ) there is reasonable assurance that the health and safety o public will not be endangered by operation in the proposed manner, and
-(2) such activities will be cc,nducted in compliance with the Connission's-regulations, and the issuance of this amendment will not be inimical to the common defense and the security, or to the health and safety of the public.-
Date: September 24, 1990 Principal Contributors:
T. Collins A. Almond L.'Kintner l'
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