ML17053D574
| ML17053D574 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 03/03/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17053D573 | List: |
| References | |
| NUDOCS 8303170216 | |
| Download: ML17053D574 (26) | |
Text
gal% hEOy,fp e
0
~ >+a 4
fl' I
c 0
+4*4+
l I
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON,D. C. 20555
~ ~
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION r
APPENDIX R TO 10 CFR PART 50 SECTIONS III.G.3 AND III.L NIAGARA MOHAWK POWER CORPORATION NINE MILE POINT NUCLEAR STATION UNIT NO.
1 OOCKET NO. 50-220 1.0 INTRO D
~
'n FebruaIy 17,
- 1981, the fiIe protection rule for nuclear power plants, 10 CFR 50.48 and Appendi x R to 10 CFR Part 50 became ef fective.
This rule required at L licensees of pLants licensed prior to January 1, 1979, to submit by March 19, 1981:
(1) plans and schedules for meeting the t
applicable requirements of Appendix R,
(2) a design desciip-ti on of any mod'i fi cations proposed to provide a lternati ve safe shutdown capabiLity pursuant to Section IZI.G.3 of Appendix R,
and (3) exemption requests for which the tolling provision of Section 50.48(c)(6) was to be invoked.
Section III.G of" AppeITdix R i s a retrofit item to all pr e-1979 plants regardless of previous safety evaluation positions
.,and resolutions.
- The criteria contained I'n Section ZII~ L of Appendix R are used for those cases
~here Licensees are incor-V'orating alternate or dedicated shutdown capability.
The staff.'s previous fire protection Safety Evaluation Report (SER) dated July 27'979i indicated that the licensee had committed to instalt.
remote hot shutdown panels 83031702lb 830303 PDR PDR ADOCK 05000220
l
\\
as an alternate means for safe shutdown in the event of a
fire which r esults in controL room evacuation.
An evalua-fion of this capability is provided in this Safety Evaluation CSE).
By submittals dated October 6i 'l978i January 31'979 t1arch 19r 1981'une 9r 1981r September 30'981'eptember 30'l982i October 1r 1982 and December 3i 1982r Niagara
- Nohawk, Power Corporation (Licensee) described proposed modifications to Nine Nile f'oint Unit 1r to meet the requirements of Appendix R to 10 CFR Part 50m Xtems XII.G.3 and III.L.
The licensee also responded to staff requests for additional.information transmitted to the Licensee by Letters dated February 20'981'pril 26'982 and November 3r 1982.
Additional information and clarification was obtained during a meeting held on November 15'982.
The maj capabi lity is "Appendix "R" ority of the information on the safe shutdown provi ded in the Li censee's'eport entitled/
I
- Review, Safe Shutdown Analysis""enclosed with the October 1,
1982 letter.
The Licensee has provided a 'safe shutdown ana lysis for fire events and has demonstrated that adequate systems and
'redundancy exist and/or alternative safe shutdown capability is available.
Our evaluation of this folLows.
/
1
- 2. 0 POST-FIRE SAFE SHUTDOWN CQPAJJJ 'IZY
- 2. 1 Systems Required for Safe S.hut.dms e
Shutdown of the reactor.
and reactivity contra L is provided by the contr ol rods.
Primary coolant inventory makeup is not required immediately, after scr am but is subsequentLy provided by the diesel driven fire pump and controL rod drive pump.
Reactor cooLant pressure control is maintained by the primary relief valves.
Decay heat removal is provided by the emergency condensers in hot shutdown and the shutdown cooling system~
reactor bui lding closed Loop cooling water
- system, and emergency servi ce water system in cold shutdown.
The dieseL generators are cooled by the dieseL generator I
cooling water system.
2.2 r
as Where ALterna e
tdown i.
e uire The Licensee has determined the need for alternate. safe shut-down capability in the event of a fire within the control complex (main control room, auxiliary control (relay) room and cable spreading room) as redundant safe shutdown equip-ment and cab ling cannot meet the requi rements of Appendix R
Section III.G.2.
The Licensee has provided aLternate safe shutdown capability independent of cabling and equipment in the controL comp lex.
2.3 Section III.G.2 of d'he licensee also indicated that aLL other areas of the plant not required to have an alternate safe shutdown system will be in compliance with the requirements of Section III G 2 of Appendix Rr unless an exemption request has been approved by the Commission.
The licensee requested five exemptions to certain provisions of Appendix R which are being evaluated and will be the subject of a separate licensing action.
2.4 ALternate Safe Shutdown S st The alternate safe shutdown system requir ed for the control complex uti lizes existing pLant s'ystems and equipment as iden-tified in Section 2.1 and two existing electricaLLy indepen-dent and isolated remote shutdown panels.
The panels are Located in separate areas of the plant.'ot shutdown uti Lizing the emer gency condensers is initiated and maintained in a
passive manner without the need for AC-power'or additional'upport equipment.. Ther efore~
a dieseL generator will not be provided for hot shutdown as par t of the -alternate shutdown system.
Nodifications are required to assure availability and automatic
~. initiation of the emergency condensersi and to prevent excess'ive reactor inventory loss in the event of a control complex fire and subsequent evacuation of the controL room.
These consist of changes:-
to the existing emergency condenser initiation and isoLation Logic circuits by relocating por.tions of them outside the control complex.
I'
The emergency condenser isolation valve control cir cuits power supp lies wi L L be modi vi Fd to provide isolation bq a control switch/ r clay combination in order to insur e va Lve operabi lity at the remote shutdown panels or controL room in the event of a fire at either Location.
Further~
the automatic depres-surization system Logic circuits and reactor head vent valve controL wiring will be modified to prevent spurious opening of the e lect romati c.'e lief valves and head vent valve.
In addition, the core spray system isoLation vaLve controL power wir ing wi Ll be modified to assure cor e spray isolation valve operability from outside the control complex.
Controls for one train of emergency condenser system valves a'e Located at each remote shutdown panel.
Complete safe shut-down instrumentation is also provided at each paneL.
Other'han the emergency condenser and its associated equipment, no additiionaL support components are required to initiate and maintain hot shutdown for at Least one'our and a's Long as eight hours.
Repairs are required to provide Local manua.l control. of a diesel generators control rod drive pumps shutdown cooling system pumps reactor buiLding coLsed Lo P
op cooling system pumps and emerg'0ncy service water system pump for achieving coLd shutdown-Local manual valve operation is also available throughout shutdown.
Further discussion of the remote shutdown panels and repair re" qujrements is contained in Section 3.0.of this report.
The 'existing
implant design and modifications assure availability of equipment essential for achieving safe shutdown assuming loss of off-site power in the event of a fire in the control complex.
- 3. 0 HIALUATION 3
1 The alternate shutdown system described in Section 2.4 wi Ll enable the achievement of the performance goals. out-lined in Section III.L of Appendix R as foLLows:
3.'t 1
c Safe shutdown of the reactor is performed by manuaL scram of the controL rods from the control room.
The controL rods aLso provide subsequent reactivity control during cooldown.
,3 1
2 2
The Licensee has performed an analysis to confirm that 2
r'eactor coolant makeup is not immediateLy.required upon initiation of the.aLternate shutdown system.
The anaLysis shows that the core remains covered for at Least 8
hours W
assuming maximum ai Lowable techni ca L speci fi cation leakage (25 gpm) and automatic initiation of the emergency condensers s
with corr esponding reactor vessel isolation (main steam isolation valve closure) when Low-Low water Level is reached in the r eactor vessel.
In order to assure the va t'idity of
the Latter assumption~
the licensee indicates that controL room evacuation procedures wiLL require both a
manuaL scram and manuaL reactor vesseL isolation be performed prior to Leaving the controL room.
The main steam isolation valves can also be closed by deenergizing power at the breakers outside the control complex.
Makeup-to -the reactor vesseL is avaiLable after approximate ly one hour of emergency condenser operation by utilizing the direct diesel driven fire pumps and the existing interconnection to the feedwater system.
Once the diesel generator is repaired, makeup can be provided by a control rod drive pump.
3.1.3 Reactor Coolant Pressure Contr Reactor coolant.-pressure contr ol i s provided by the r eLi ef valves and emergency condenser operation with backup pressure control and overpressure protection provided by the safety/
relief valves.-
3.1.4 or Deca Heat emo Decay'eat removal in hot shutdown is accomplished through the use of the emergency condensers.
Makeup to the secondary side of the emergency condensers is supplied automatically gt by gravity flow from the makeup water storage tanks.
~,
<<8>>
7 The Licensee stated that sufficient water is avai labLe in the P
makeup tanks for eight hours of emergency condenser operation.
Backup makeup for Long term operation of the emergency condensers is provided by the condensate surge and storage tanks via.the condensate transfer pumps.
Makeup is also avaiLable to the makeup tanks from the di rect di ese l dri ven fi re pump.
The emergency condenser operation is controlled from the remote shutdown paneLs where valve control switches are Located.
Decay heat removal jn cold shutdown is provided by the shut-down cooli'ng system, reactor building, closed loop cooling water
- system, and emergency service water system.
Util'iza-.
tion of shutdown cooling requires repair
'as discussed in Section 3.3~
manuaL vaLve operation, and remote Local pump control
~
.ss Monitor Direct indication of process variabLes including reactor vessel Level, reactor
- pressure, reactor temperature, dryweLL temperature and pressure torus temperature>
and one train'f emergency condenser leveL is provided at each remote
l.
~ I shutdown panel Makeup tank level indication is available at a
Local indicator.
Diagnostic monitoring (Local indication) avai lable incLudes emergency service
~ater system pressurei reactor building closed Loop cooling water system temperature and f low and shutdown cooling system pr essure.
3.1. 6
'Other than the station batteries, no other support functions are immediately necessary for achieving -hot shutdown.
The dieseL generators, diesel generator cooling water
- system, reactor'uiLding cLosed Loop cooling water system shutdown cooling systems and emergency service water system will be available to provide necessary support functions for the al-ternate shutdown system following repair.
- 3. 2 72-Hour Re The Licensee has achieve cold shut indi cated that the capabi lity exi'sts to down within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after a fire event
'ssuming no offsite power is available.
3.3 Repai t s A number of repai shutd'own fo L Lowin 3
with Appendix R
c rs are required in order to achieve cold g
a control complex fire in accordance riteria.
These include. the foLLowing:
3.3. 1 DieseL Generator In order to provide the capability to start and operate a
diesel generator at the existing Local contro l pa'nel, a
new DC feeder cable must be pulled and various wires disconnected.
Fuses must be pulled in order to provide the capability to Load the eLectricaL power bus.
The above repair must be completed within eight hours as dictated by the alternative shutdown system design.capabiLity.
3.3.2 Control Rod Drive Pu In order to provide the capabiLity to LocaLly start:a controL rod drive pump for vesseL
- makeup, pump control wirin'g must be disconnected and a fuse pulled.
In addition, a
hand wheel is avaitable for manual operation of the pump dis-charge flow controL valve.
3.3.3 Decay Heat Remova L System for Cold Shutdown In order to provide the means for initiating cold:shutdown, control wiring must be disconnected and fuses puLLed for a
shutdown cooling pump, reactor bui Lding closed Loop co'oling pump and emergency-service water pump.
Jumper installation i s a Lso requi red.
In addi ti on~ manual hand wheels are avai lab le for manual operation of valves in the above systems.
3 ~ 3 ~ 4 ~i
. I,a~
',p g gJ The Licensee will develop detailed procedures for ~ the above repairs based on a worst case fire damage condition.
The
~'
procedures wiLL*include necessary guidance on onsite repair equipment Location and time estimates for accomplishing repairs.
Sufficient manpower is available for assess'.ng fire damage~
maintaining hot shutdown~ fire fighting, and performing prescribed."repairs.
Nq qpecial material is required to accomPlish the cold shutdown rePairs ALL necessary material is dedicated and stored onsite during normaL operations'.
3.4 Associated Circuits an I
I
.The licensee conducted a review of the present elect'rical systems to determine the plant'.s capabi lity to meet the L
associ'ated circuit criteria as stated 'in Appendix R relating to safe shutdown and concluded that the existing electricaL insta llation with some addi tiona L equi pment modi fi cations wouLd satisfy these cr'iteria.
Nodifications as discussed in Section 2.4 are necessary to the circuitry for the emergency condenser valves in order to assur e their.operabi l-ity in case of fire.
The Licensee addressed associated circuits of concern as discussed below.
3..4.1 ommon Power S
u The licensee stated that all instr umentati'on and power cir-cuits are protected or wi Ll be provided with coordinated p'o-tection by either circuit breikers or fuses.
4
- 3. 4. 2 Common E
3.4.3 As in the common power s.ource
- case, the Licensee stated that associated circuits that share a
common enclosure with those required for safe shutdown are provided with isolation devi ces (breakers, fuses, etc.).
uri ous Si na Ls
.The Licensee stated that fires in the controL complex can cause spurious signa ls which could impact safe shutdown.
Therefore, the electricaLly isolated remote shutdown panels and other circuit modifications as discussed in Section 2.4 are r'equired.
Modifications to provide eLectrical isoLation wiLL be made Co the emergency condenser isolation Logic circuitry to assure.against spurious-isolation of the'mer-gency condenser
.on high steam f Low/break anZ high radiation signals.
Modi fi cati ons to provide electri ca l isolation wi L L be made to the automatic depressurization system initiation circuitry and reactor vessel head vent controL wiring in order to prevent spurious opening of the electromatic relief valves and head vent va lve.
Various other power op'crated
'alves including the shutdown cooLing system high/Low pres" sure interface isolation'valve wiLL have their power supply deenergized during normal and power operation to prevent their spurious operation.
E.
~
~
~ ~ ~
- 3. 5 Saf e. Shu.tdowz Pwocedu,res a.n.d Haa~~r The Li censee wi L L revi se'xi st ing saf e shutdown procedures to incorporate the above described alternate shutdown method.
The Licensee further states that the revisions wiLL be made to assure that the necessary shutdown functions'an be performed at aLL times by manpower available.
- 4. 0 CONCLUSION We have reviewed the Licensee's proposed alternate
.shutdown capabiLity for Nine MiLe Point Unit. 1.in'ccordance with Appendix R criteria.
Based on that review, we conclude that.the performance goals for accomplishing safe shutdown in the event of-a fi re, i. e.,
r cacti vity control, inventory
- controL, decay heat
- removal, pressure contro l, process monitoring and support functions are met by the proposed alternate.
Therefore, we conclude that the requirements of Appendix R, Sections III.G.3 and TXI.L are satisfied for fire areas within the control complex
~
Dated:
March 3, 1983 Principal Contributor:
J.
Wermiel
~
~
A