ML20012E847
| ML20012E847 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 03/23/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20012E844 | List: |
| References | |
| NUDOCS 9004060434 | |
| Download: ML20012E847 (6) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.158 TO FACILITY OPERATING LICENSE N0. NPF-1 t
PORTLAND GENERAL ELECTRIC COMPANY THE CITY 0F EUGENE. OREG0N PACIFIC POWER AND LIGHT COMPANY TROJAN NUCLEAR PLANT DOCKET N0. 50-344
1.0 INTRODUCTION
On Decer.ber 15, 1989, the licensee declared both chlnrine detection systems for control room ventilation inoperable when no documentation could be found to show that the response time of the detectors meet the
' design basis responste time as given in the FSAR. Following a period of testing and analysis to confirm the operability status of the detector systems, the licensee determined on or about December 22, 1989 that no basis could be found for restoring operability of the detectors other than replacement with new qualified detectors. By-letter dated December 27, 1989, the licensee confirmed their intention to replace the detectors and requested a temporary change to Technical Specification (TS) 3.5.3.6.b that would permit continued safe operation of the facility while new detectors are qualified, installed and made operable.
2.0 EVALUATION Per Action Statement 3.3.3.b. the control room emergency ventilation (CREV) must operate in the recirculation mode while one or both of the chlorine detectors are inoperable. While operating the CREV in the i
recirculation mode, carbon dioxide levels build up to unacceptable levels in the control room (CR) atmosphere so that the licensee would be forced to exit T.S. 3.3.3.6.b by opening the CR vents to outside air for brief periodsoftime(lessthanonehour). This exit from T.S. 3.3.3.6.b because of intolerable atmosphere in the CR is allowed by TS 3.0.3 which l
provides for Action to be taken when neither the LCO nor the associated j
action statement can be met.
On or about December 22, 1989, the licensee determined that the chlorine detector systems could not be restored to operability, but that acceptable chlorine detection capability could be restored by installation of new qualified chlorine detectors by March 15, 1990.
Since the purpose of the
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chlorine detectors is to ensure that CR operators are not exposed to unacceptable levels of chlorine in the CR atmosphere, the licensee has proposed specific compensatory measures that will ensure protection of CR personnel from excessive levels of chlorine in the CR atmosphere until j
qualified chlorine detectors are in place and operable. The specific compensatory measures to be taken are described below.
AsdescribedintheTrojanFinalSafetyAnalysisReport(FSAR), chlorine onsite is stored in the Chlorine Building. To minimize the probability of a release from this source, the followinq compensatory measures are taken when both chlorine detectors are inoperable and outside makeup air is being brought into the Control Room:
1.
flo chlorine shipments may be received.
2.
No evolution / activity involving the use of chlorine in the t
Chlorine Building are permitted, and 3.
Chlorine levels will be monitored in the Chlorine Building.
These measures will ensure that the probability of a chlorine release from the Chlorine Buildino will be no greater than that previously analyzed in the FSAR and that any chlorine release from the Chlorine 1
l Building will be promptly detected and reported to the Control Room.
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l Also as described in the Trojan FSAR, offsite trans)ortation of chlorine occurs on the Burlington t!orthern railroad tracks w11ch are 150 meters
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l west of the Plant, and on the railroad tracks 1800 meters cast of the Plant on the Washington side of the Columbia River. To quard against L
possible chlorine accidents from the railroad tracks west of the Plant, the following compensatory measures are taken when both chlorine detectors ere inoperable and outside makeup air is being brought into the Control Room:
1.
Connunications are established between the Control Room and a quard in observation of the railroad tracks west of i
Trojan to alert the Control Room of passing trains, and l
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Outside air makeup derpers (CB-1 and/or CB-2) will be closed I
and the associated ventilation system stopped whenever a L
train approaches and passes Trojan on the railroad tracks west of the Plant.
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To detect possible chlorine accidents on the railroad tracks east of the plant when both chlorine detectors are inoserable and outside makeup air is being brought into the Control Room eitler:
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An observer will be posted who can observe the railroad tracks east of Trojan on the llashington side of the Columbia River and report any train derailment, and l-
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Outside air makeup dampers (CB 1 and/or CB-2) will be closed and the associated ventilation system stopped whenever a i
train derails on the railroad tracks east of Trojan on the 1
l Washington side of the Columbia River.
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Comunications will be established Latween the Control Room.
and an observer posted at the Intake Structure who can alert the Control Room when the odor of chlorine is detected, and 2.
Outside air makeup dampers (CB-1 and/or CB-2) will be closed and the associated ventilation system stop)ed whenever the i
observer at the Intake Structure detects tie odor of chlorine.
The FSAR lists two locations where chlorine is stored in the vicinity of Trojan.
Both of these chlorine storage locations are in Cowlitz County, Washincten.
In the event of a chlorine release from either of these locations, the Control Room would be notified of the release by the Cowlitz County Emeroency Services and Disaster Agency which has notifi-cation procedures in place.
If both chlorine detectors are inoperable, and if outside makeup air is beinq brought into the Control Room, and if notification of an offsite chlorine accident is received, then nutside air makeup dampers (CB-1 and/or CB-2) will be closed and the associated ventilation system stopped until it is confirmed that the release is terminated and poses no hazard to Trojan.
These measures will ensure that the consequences of any chlorine release from offsite transportation or storage of chlorine will be no greater than that previously ar.alyzed'in the FSAR and that any chlorine release will be promptly detected and reported to the Control Room.
The staff hes evaluated the licensee's proposed course of action for contirued safe operation of the plant until new qualified chlorine l
detectors are installed and made operable by approximately March 15, 1990, and finds the proposed course of action to be acceptable, i
3.0 EMERGENCY CIRCUMSTANCES On December 15, 1089, after discovery that the chlorine detector response time could be longer than assumed in the toxic qas analysis, both trains of chlorine detectors were declared inoperable per Trojan Nuclear Speci-i fication TS 3.3.3.6, " Chlorine Detection Systems", and the Control Room Emergency Ventilation System (CB-1B) was placed in the recirculation mode of operation as required by the appropriate action statement. This caused a conflict with TS 3.7.6.1, " Control Room Emergency Ventilation System" which reouires the Control Room Emergency Ventilation System (CB-1) to be available for automatic initiation upon receipt of a safety injection (SI) signal. With one train of CB-1 in recirculation, it was no lonoer in the automatic initiation lineup and the ACTION statement of f
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TS3.7.6.1 applies (i.e.,thetrainofCB-1inrecirculationmustbe L,
resbred to operable status within seven days). This seven day period began on December 12, 1989.
With'the Control Room isolated, carbon dioxide (C0 ) tends to build to p
unhealthy levels for habitation.
Indiscussionsw$ththeNRCon 3
De* ember 15, 1989, the NRC acknowledged PGE's need to enter into TS 3.0.3 in order to ventilate the control room to maintain habitability per Occupational Health and Safety Administration (OSHA) requirements.
Before entry into TS 3.0.3 is made, PGE takes appropriate compensatory measures to protect the control room operators in the event a toxic gas accideat occurs during the ventilation process.
Based on current data it appears that such vent 11ations need to be performed approximately every 24 to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.
The problem with the potentially excessive response time of the chlorine detectors was only recently discovered, and all available resources were a> plied to correct this problem: test equipment was obtained to determine tie actual detector response times; a reanalysis of toxic gas effects on Control Room personnel was performed to determine the actual response time necessary; and efforts were made to locate replacement detectors.
The need for this emergency change could not be foreseen or avoided.
Ilew detectors were ordered as soon as the need for them became apparent; meanwhile, plant operation will continue using the compensatory measures already described.
4.0 FillAL NO SIGNIFICANT HAZARDS CONSIDERATION DETERil1NAT10N The Commission's requistions in 10 CFR 50.92 state that the Connission
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may make a final determination that a license amendment involves no significant hazards considerations if operation of the facility in accordance with the amendment would not:
(1) Involve a significant increase in the probability or consequences of any accident previously evaluated; or (2) Create the possibility of a new or different kind of l
accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin or safety.
This amendment has been evaluated against the standards in 10 CFR 50.92.
A discussion of these standards as they relate to the amendment request l
follows.
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1 Standard 1 - Involve a significant increase in the probability or l'
consequences of an accident previously evaluated.
This change does not involve a significert increase in the probability or consequences of an accident previously evaluated.
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i The probability of.a chlorine release which could affect Trojan is unaffected by this change as the proposed change concerns mitigation of 1
a chlorine accident.
Chlorine release detection and subsequent mitiga-tion of the consequences of a chlorine accident would normally be provided by the chlorine detectors. Compensatory measures were then designed to detect and protect from chlorine releases earlier than would norn. ally be provided by the chlorine detectors.
Standard 2 - Create the possibility of a new or different kind of acc1 cent from any accident previously evaluated.
This change does not create the possibility of a new or different kind ofaccidentastheTTS4.7.6.1.bsurve'.11anceisnotchanged(CB-1 1
makeup dampers for outside air opened). Allowing for the surveillance l
to be performed with ino for a toxic gas release.perable chlorine detectors is of concern only Because of compensatory measures the Control Room can still be operated within the assumptions of the toxic gas analysis and thus does not create a new or different accident.
i Standard 3 - Involve a si nificant reduction in a margin of safety.
D This change does not involve a significant reduction in a margin of safety as compensatory measures provide for detection and notification of the Control Room in the event of a chlorine gas accident.
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The staff, therefore, has determined that operation of the facility in accordance with the proposed change does not involve a significant hazards consideration. Accordingly, the Commission has determined that this amendment involves no significant hazards considerations.
5.0 CONTACT WITH STATE OFFICIAL l
The NRC staff has notified the Oregon Department of Energy of the proposed issuance of this amendment along with the proposed determination of no significant hazards consideration. No comments were received.
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6.0 ENVIRONMENTAL CONSIDERATION
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l This amendment involves a change in a requirement with respect to in-I stellation or use of a facility component located within the restricted L
area as defined in 10 CFR Part 20. The staff has determined that the L
amendment involves no significant increase in the amounts, and no signi-ficant change in the types l
of any effluents that may be released offsite, andthatthereisnosignificantincreaseinindividualorcumulative occupational radiation exposure. The Staff has determined that the proposed amendment does not involve a significant hazards consideration.
Accordingly, the amendment meets the eligibility criteria for categorical exclusionsetforthin10CFR51.22(c)(9).
Pursuantto10CFR51.22(b),
no environmental impact statement or environmental assessrient need be prepared in connection with the issuance of the amendment.
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7.0 CONCLUSION
i We have concluded based on the considerations discussed above, that (1) j thereisreasonableassurancethatthehealthandsafetyofthepublic i
will not be endangered by operation in the proposed renner, ion's regu-
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(2)such activities will be conducted in compliance with the Commiss 1ations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
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PRINCIPAL CONTRIBUTOR:
Roby Bevan Dated: March 23, 1990 i
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