ML20062J569
| ML20062J569 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/15/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20062J566 | List: |
| References | |
| NUDOCS 8010310138 | |
| Download: ML20062J569 (4) | |
Text
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SAFET/ E'leLJATION BY THE CFFICE CF NLCLEAR REACTOR REGULAT:CN REleTED TC -eENCPENT NO. 33 TO FAC:L:T/ CPERAT:NG :CE:lSE NO. CPe-66 k'LUEE lf u:Gn? CMP ANY CH:0 ED:SCN :CPPANY
?E:eliSYL /Ali:A :C ER CC:PAa7 3EAVER VALLEY PG' ER STAT:CN, UNIT NO.1 00CKET NO. 50-324 L
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Introduction During normal plant operation at the Beaver Valley Power Station, Unit 1, outside air is drawn into the control rocm ventilation system.
Foll owing a design basis accident, the control room ventilation system is auto-matically isolated.
Battled air is released anc a separate recircula: ion system acts as the control roem's ventilation system.
Technical Scecification Table 3.3-5 states that following a containment isolation Phase 3 signal, the control room ventilation system must be isolated within 17 or 30 seconds, decending on whether offsite cower is available or unavailable, resoectively.
In a letter dated Sectemcer 30,1980 (see reference), the licensee stated tnat cue to a tycograonical error :ne stated isolation times were incorrect and that the actual isolation times should be 22 and 77 seconds respectively.
The licensee has tnerefore requested an emergency Technical Scecificatien enange so that the clant can be brougnt back to power without violating -he acceptance criteria c' the Technical Soecifications.
Evaluation During normal power plant conditions the containment builcing coerates under sucatmospneric conditions, :ne Sucalementary Leak Collection anc Exnaus: System (SLCRS) maintains a slignt vacuum (1/5" water gage) in the contiguous area surrounding the containment, anc cu:sice air is I
drawn in to serve the control roem ventilation system.
This design assures tna: only inleakage into tne containment takes place and tna:
- ne control room ventilation system uses uncontaminated air.
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Followi.1g a design basis ac:1 dent, ne Containment Isclation Pnase o signal initiates several actions.
(The pnase 3 isolation signal is ac*uated on a contairment qicn-nign ressure se coin; of 10.0 osic.)
vo'ncicent wi:n tne Phase 3 isolation signal is -he elease of the bet:lec air anc One actuation of :ne recir:ulation fans in ne control rocm.
The camoers wnien release :ne bottled air to :ne control roem are L C. solenoid ocerated oneuma ic valves :na: will move to their accident position regardless of.he availability of emergency power.
The bottled air system is comorised of five separate tanks.
Each tank is orificed so that a maximum of 100 cfm from eaca :ank enters one control room following a Phase 3 isolation signal.
The control room only requires 400 cfm for normal ventilation purposes.
The additional 100 cfm provides both a margin and the positive pressure (additional instruments have been installed for over-cressure protection) in the control room. Since the bottled air tanks are orificed, the increase in time to isolate the control room ventilation system should have a negligible effect on the adequacy of the system's inventory.
The bottled air enters the control rocm at 500 cfm and creates a positive pressure. The outside air flew from the normai control room ventilation system is temporarily reversed.
Settled air escaces the control rocm through the normal ventilation system during the time period between actuation of the Phase 3 isciation signal and isolation of the control rocm ventilation system. This occurs at either 22 or 77 seconds after tne Phase 3 isolation signal cecending on wnether offsite ocwer is available or unavailable, rescectively.
This design assures tnat only outleakage occurs from the con:rci roem during an ac:iden*
and :nat contaminated air is prevented frem entering.
In addition to the centrol recm ventilation system, the SLCRS also experiences a post-accident change of mode.
Sucsequent to the Phase A isolation signal, (Phase A is actuated by either a containment nicn pressure setooint of 1.5 psig or a safety injection signai), bypass dampers redirect the exhaust througn an emergency filter train before the air is released througn the plant stack. The emergency filters reduce the potential of radicactive gases reaching One control room ventilation intake system. The emergency fil:er trains of the SLCRS are ac uated and effective at leas 15 seconds cefore One con:rci room ventilation System is isolated - depending on ne time interval between the containment pressure rising from :ne hign cressure :o the hign-high pressure setpoints.
!n summary, ucon receipt of a Phase A isolation signal (safety injection or containment hign pressure of 1.5 psig), the SLCRS redirects the
.exhaus: :nrougn a separate emergency hign efficiency filter train.
At :nis time :ne control rocm ventilation system is still drawing in cu:sice air.
Isolation of :ne controi roem ventilation system and actuation of the bottled gas system coes net oc:ur until a :hase 3 isolation signal (containment hign-hign pressure of 10.0 psig) is reacned. The licensee has cnosen Oc isciate the con:rci rocn. on the Phase 3 signal ratner than the Phase A signal so that the bottled gas system woulc not be decleted on spuriour safe:y injection signals.
Increasing the Technical Specification limi: cn isolating the control rocm ventilation system following a Phase 3 isolation sicnal nas an insigni-ficant effect because the licensee has snown tha: curing this time interval :he only leakage will be outieakage of bottlec air from the control rocm. The licensee's procosec technical s:ecification change
' has no effect on this ascect.
We concluce :na: there are nc unac:sota:ie safety imolications associated wi:n the :nange, :ne : ange dcas nc-c:nstitute an unreviewec safety cuestien, an:, :na: :ne :nange is enerefore ac:ectacle.
Envirerrectal
- nsdoeratton We have ce:ere.ined tha: he amendment dces not authar :e a cnange in d
effluent types or total amounts nor an increase in :cwer level and will not result in any significant envirenmental incact. Having 7 ace
- nis determination, we have further concluded tha :ne amencment involves an action nnich is insignificant from One standecia: of enviremnental ie:act and, pursuant to 10 CFR j51.5(d)(4), tha: an environmental incact statement or negative declaration and environ-mental imcact acprai;al need not se prepared in connec:f on with ne issuance of :his amencment.
C:nclusion We nave concluded, based on the considerations discussed accve, that:
(1) because the snendment does nct involve a significant increase in the pr:bability or consecuences of accidents previously ::nsidered and sces not involve a significant cecrease in a safety margin, :ne amendment does not involve a significant ha:ards c:nsideration, (2) here is reasona:Te assurance that the health and safety of the :ucife will not :e endangereo by ocers:fon in the procesec manner, and (3) sucn activities will be conducted in concliance with the Ccmmission's regulations and the issuance of this amendmerm will act be inimical 10 the ::r. mon 2efense and security or to the nea!:h and safety of ne OUolic.
Date: October 15, 1990
.4.
Re ferences Letter from Ouquesne Light Comoany (C. N. Dunn) to V. S. Nuclear Regulatory Commission (Director, NRR) dated September 30, 1980.