ML20096F394
| ML20096F394 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 04/20/1992 |
| From: | Schrage J COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20096F398 | List: |
| References | |
| NUDOCS 9205210158 | |
| Download: ML20096F394 (9) | |
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- 1400 opus Place..
4 C Down:rs Grove, Illinois 60515 l
April 20,1992 Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation -
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U.S. Nuclear Regulatory Commission =
Washington, D.C. 20555 Attn: Document Control Desk
Subject:
Quad C! ties Station Units-1 and 21 Proposed Amendment to Facility Operating Licenses DPR 29-and DPR-30, Appendix A, Technical Specifications NRC Docket Nos. 50-254 and 50-265
References:
- (a) i Regulatory Guide 1.78, Revision 0, June,1974,1.-
" Assumptions for Evaluating the Habitability of a Nuclear.
Power Plant Control Room During a Postulated Hazardous Chemical Release."
(b) Regulatory Guide ~1.70,' Revision 3, November,1978 -
" Standard Format and Content of Safety Analysis. Reports.
i for Nuclear Power Plants."
(c) Report SL-7125, Revision 1, ~Aaril,1991, " Habitability of Control 3oom Following Postu ated Accidents involving L
Chlorine and Sulfur Dioxide Shipments in The Vicinity ofl
' Quad Cities Station." (copy attached)(
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Dear Dr. Murley:
Pursuant to 10 CFR 50.90l Commonwealth Edison Com
'(CECO)1 3roposes to amend Anondix A,-Technical Specifications, of Faci deledon of the.
ratlin :q Licenses DPR-29 anc )PR-30.nThe proposed amendment requ
- isolation functions and surveillance requirements for the C'ntrol Room' Ventilation:
System chlorine and sulfur lioxide analyzersBThe propoud change would reduce i unwarranted challenges to the Control Room Ventilation System due to saurious :
isolation actuation of the chlorine and sulfur' dioxide analyzers, thereby m nimizing :
U unnecessary reporting of ESF actuations.; This request is based upon an analysis which indicated that these isolation functions are not required to ensure Control Room:
Habitability following a postulated accident involving chlorine and sulfur dioxide -
shipments in the vicinity of Quad Cities Station;
. This propored amendment request is presented as follows:~-
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1.
' Attachment A provides'a summary of the proposed changes.
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- 2.
A'ttachrent B provides a description and safety analysis of thei proposed changes in_this amendment.
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Dr. Thomas E. Murley April 20,1992 3.
Attachment C provides the marked up Technical Specification pages with the requested changes indicated.
4.
Attachment D describes CECO's evaluation performed in accordance with 10 CFR 50.92 (c), which confirms that no significant hazards consideration is involved.
5.
Attachment E provides the Environmental Assessment of the proposed changes.
6.
Attachment F provides a copy of Reference (c).
This proposed amendment has been reviewed and a3 proved by CECO On Site and Off-Site Review in accordance with Commonwealt1 Edison procedures.
To the best of my knowledge and belief, the statements contained above are true and correct, in some respect these statements are not based on my personal knowledge, but obtained information furnished by other Commonwealth Edison employees, contractor sm aloyees, and consultants. Such Information has been -
reviewed in accordance w th company practice, and_1 believe it to be reliable.
Commonwealth Edison is notifying the State of lilinois of this application for amendment by transmitting a copy of this letter and its attachments to the designated state official.
Please direct any questions or comments to me at (708) 515 7283.
Sincerely,
/.4-ohn L. S rage Nuclear Licensing Adminstrator L
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Dr. Thomas E. Merley. April 20,1992 Attachments:
A.
Summary of Proposed Chan s.
B.
Description and Safety Anal is of the Proposed Changes C.
Marked-up Technical Specif ation Pages D.
Evaluation of Significant Hazards Consideration.
E.
Environmental Assessment F.
Copy of Reference (c) cc:
A.Bert Davis - Regional Administrator, Region lli L.N. Olshan - NRR Project Manager, Quad Cities T.E. Taylor - Senior Resident inspector, Quad Cities Office of Nuclear Facility Safety -IDNS Signed before me on this N day of b;
.1992, by: T
~Not(r/ 'ublic -
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sA OFFICI AL p
a H01 Agy NBUC,5h or tWH0tS SANDRA g. 6/.25194 gy COMMISS10M
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ATTACHMENT A Summary of Proposed Changes
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The following changes are being proposed for Ouad Cities Station Units 1 and 2 Technical Specifications:
1.
DPR-29 and DPR 30; Page 3.2/4.2 3
- Delete the chlorine and sulfur d(ioxide analyzers. Limiting Cond (a) 4 (b)
(DPR 30 only) Limiting Condition for Operation (LCO), Technical-Specification 3.2.F.1 - Correct a typographical error. " Streamline" should be "steamline."
2.
DPR-29; Page 3.2/4.2-11 DPR-30; Page 3.2/4.2-8 Change the Bases for Technical Specification 3.2.F.2 to reflect deletion of the isolation function for the chlorine and sulfur dioxide analyzers and correct.
a typographical error (DPR-30 only). The word "Gireamline should be-
"steamline.'
3.
DPR 29; Page 3.2/4.2 28 DPR-30; Page 3.2/4.2-17 Delete the chlorine and sulfur dioxide toxic gas analyzers from Table 4.21.
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i ATTACHMENT 0:=
osseription and safety Analysis of am Proposed Changee 8
Summary Commonwealth Edison Company proposes to amend the Technical Specifications for Quad Cities Station Unit 1 (DPR 29) and Unit 2 (DPR 30). The -
proposed amendment would delete the isolation functions and surveillance :
requirements for the Control Room Ventilation System chlorine and sulfur dioxidel snalyzers; correct a typogral)hical error; and, modify the corresponding Bases sections to reflect the deletion of the ' olation function and correction of the typogra)hical error.
s The proposed change would reduce unwarranted challenges to the Contro RoomJ _
Ventilation System due to spurious isolation actuation of the chlorine and sulfur dioxide analyzers, thereby minimizing unnecessary ESF actuations.1The deletion of the -
isolation functions for the chlorine and sulfur dioxide analyzers is based upon a recent analysis (April,1991) which indicates that these functions are not required to satisfy.
Reference (c))i This analysis and the control room habitability requirements (d as Attachment F. Commonwealth Edison will
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corresponding conclusions are provide retain the control room annunciator alarm function for the chierine and sulfur dioxide analyzers. -
Descriplian and Basse of the Cummt Flequirement Prooosed Chance 1.a. 2 and 3 ~
chlorine and sulfur dioxide as toxic substances'which should b(e considered when -R evaluating the habitability of a nuclear power slant control room durin postulated?
hazardous chemical release. The hazard to tle control room habitab due to a -
partcular toxic chemical depends upon the distance the material is sto from the control room, the quantity of the material stored on or near the site,'and the frequency,-
distance and quantity of the material transported near the site.' in addition, the
_ prevailing wind direction affects the likelihood that an accidental release will reach the control room ventilation air intakes.
The Control Room Ventilation System at Quad Cities SUtion consists of: two air handling systems, an air filtration system; a smoke detection system; and a toxici 4
gas analyzer system.oThe toxic gas analyzer system provides toxic Ga? protection to the control room emergency zone in case of either an onsite or offsite toxic chemical 4
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accident. Potential accidents, including their effect upon control room habitability have bc m analyzed in the " Control Room Habitability Study for Quad Cities Unit 1 and 2,;
r,mmonwealth Edison Company, Revision 2" dated June 114,1982.-
1 1
The Control Room Habitability Snly was developed in response to NUREG 0737, item lli.D.3.4 and submitted to the NRC in 1982.?This study included a 1981' L
- survey for soientially toxic chemicals stored or transported onsite or within a 5-mile L
- radius offs te of Quad Cities Station.;The 1981 surve provided information which was used as_ input to the Control Room Habitability Study CRH);tThe CRH Study indicated; that concentrations of chlorine, ammonia, and sulfur ioxide would exceed toxicity _
4 levels in the control room in less than two (2) minutes. '. Based upon this information, analyzers were installed in the control room air intake to detect these chemicals and ;
isolate the control room upon detection;
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The toxic g:s cn:lyz:r syst:m provides protection from tha cn:lyz:d cccid:nts through cither cutom tic or minu:11:ol: tion. Monitors cnd tutom; tic -
4 Isolation functions are provided for ammonia, chlorine, and sulfur dioxide since the control room concentrations for these chemicals reach the toxic 4y limits faster than the operator can manually isolate the system after detection of odor. Manual action to isolate the control room is rec;uired for other chemicals whose control room concentrations do not exceed the toxicity limits within 2 minutes after detection of odor.
The chemicals requiring operator action are hydrochloric acid, hydrofluoric acid, nitric acid and benzene.
The toxic gas analyzers continuously monitor the outdoor air intake of the operating air handling system. Upon detection of either ammonia, chlorine, or sulfur dioxide, the analyzers provide a signal which isolates the control room HVAC system outside air intakes, and annunciates in the control room. Trip setpoints and surveillances for the toxic gas analyzers are described in Sections 3.2.F and 4.2.F of the Quad Cities Station Technical Specifications (Appendix A of Facility Operating Licenses DPR 29 and DPR 30. Technical Specificat!on (TS) 3.2.F.1 defines the type of signal which will cause an is)olation of the Control Room HVAC system. This includes high toxic gas concentration. TS 3.2.F.2 defines the toxic gas detection instrumentation, including trip setpoints. Suiveillance requirements for the toxic gas analyzers are defined in TS 4.2.F.1, and described in Table 4.2-1.
Er000SaiChanga 1.b and 2 (DEfMQAnly)
The change of " streamline" to "steamline" is the correction of a typographical error, and as such is an administrative change.
Desciiption of the Neod for the Proposed Change This amendment to the Technical Specifications is being requested to reduce unwarranted challenges to the Control Room Ventilation System due to spurious isolation actuation of the toxic gas analyzers, thereby minimizing unnecessary ESF actuations.
The immediate Notification and Licensee Event Report (LER) ruids defined in 10 CFR 50.72 and 10 CFR 50.73 require reporting of "any event or condition that results in a manual or automatic actuation of the Gngineered Safety Feature (ESF)" (10 CFR 50.72 (B)(2) (ii) and 10 CFR 50.73 (A) (2) (iv). Therefore, either automatic or manual isolation of the Control Room Ventilation S)ystem is reportable within fou hours by telephone (ENS Notification) and within 30 days as an LER.
From October 1986 through February 1992, Quad Cities Station experienced nine (9) ENS notifications and corresponding LERs directly related to an automatic ESF these LERs can be attributed to equipment malfunctions. The other LER was(8) actuation caused by the chlorine and sulfur dioxide detection monitors. Eight attributed to personnel error. Considering the low realistic probability of accident occurrence shown by the analysis, the spurious isolation actuation of the chlorine and sulfur dioxide detection monitors (thus causing an ESF actuation) presents an unnecessary challenge to a plant safety system. Therefore, removal of the isolation functions provides a net improvement in plant safety.
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Bates forthe Proposed Change Proposed Chanoe 1.a 2 and 3 l
The original 1981' survey for aotentially toxic chemicals stored or transported onsite or within a 5-mile radius of Quac' Cities Station (as discussed above) and Control Room Habitability Study indicated that chlorine and sulfur dioxide monitors and iso:stion functions were necessary in order to ensure control room habitability. -
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- A'second survey was conducted between February and April 1988 in order to supplement the 1981 survev..The purpose of the second survey was to gather L
additional data needed to perform quantitative analyses of the Quad Cities Station
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Control Room habitability and exposure risk due to accidental releases of chlorine and -
sulfur. dioxide. Two distinct types of analyses were pe: formed. The first analysis
-looked at the dispersion of the vapor released from a postulated accident to the station
- and subsec uent infiltration into the control room. The results of this analysis indicated -
L that the tox city limits of chlorine and sulfur dioxide would be exceeded in the control room within two minutes of detection.
T Since the dispersion analysis showed that the calculated chlorine and sulfur -
I dioxide concentrations exceeded the toxicity limits, a probability analysis was o L
periormed in accordance with the Standard Review Plan (SRP) (NUREG-0800) Section L
2.2.3 and Regulatory Guide 1.70 (Referenced (b)). The SRP references RegJ Guide L
1.70 for identification of design basis events resulting from the presence of hazardous--
materials or activities in the vicinity of the plant.T Acceptable identification of the des!gn.
basis events includes each postulated. type of accident for which the exsected rate of:
occurrence'of potential exposures in excess of the 10 CFR Part 100 delines is.
estimated to exceed the N RC staff objective of approximately 1 X 10' / year.4The SRP.
L recognizes the difficulty of assigning accurate numerical values to the expected rate of -
unprecedented potential hazards generally considered in SRP Section 2.2.3; therefore,.
l Juc gment must be used as to the acceptability of the.overall risk p esented. iThe SRP also states that because of the low probabilities of the events under consi.deration, data are often not available to permit accurate calculation of probabilities. Accordingly, the -
expected rate of occurrence of potopial exposures in excess of the 10 CFR Part 100 s
_ guidelines of approximately 1'X 10' / year is acceptable if, when combined with-reasonable qualitative arguments, the probability can be shown to be lower.
- A third survey (Reference c) and Att6chment F) was conducted between
- October and November 1990 in orde(r to supplement the 1988 data.1The purp
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the third survey was to gather more recent data needed to seriorm quantitative.
. analyses of the Quad Cities Station Control Room Habitability and exposure risk due to accidental releases of chlorine and sulfur dioxide.
Of the three modes of transportation surveyed, chlorine and sulfur dioxide -
shipment by rail was found to be the controlling mode for the habitability analysiscThe survey revealed that between the years of 1986 and 1989, the Soo Line's maximum shipment was 276 tank cars of chlorine and 144 tank cars of sulfur dioxide.1 Alsor during those years, a mal num of 29 tank cars of chlorine and 45 tank cars of sulfur--
dioxide were shipped by the Chicago & Northwestern Railroad..
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The surv;y found th t tho Soo Lino cnd Chic:go N;rthwestwn Rt: fronds cra 3
the cnly shippers of suffici:nt qu:ntities of chl:rine cnd sulfur dioxide to cff:ct control room habitabilitt The equation used to evaluate the hazard to the control room considered the pobability of occurrence of an accident resulting in control room uninhabitability (accident / year), the probability of the accident with chemical release (accidents / car / mile), the frec uency of shipment (cars / year), length of track in each sector (miles) and the probaallity under certain stability classes that wind is blowing in a direction such that released chemical is carried to the control room air intake. The analysis followed applicable Regulatory Caldes, the Standard Review Plan and used other references as documented in Section 8.0 of Attachment F. The results of the probability analysis are discussed in Section G.0 of Attachmont F and indicate that the conservative risk exposure of causing uninhabitable control room conditions by b
accidents involving railroadphipments of chlorine and of sulfur gioxide have been calculated to be 6.29 X 10' occurrences / year and 1.282 X 10' occurrences / year, respectively. The qualitative arguments presented in Section 6.0 of Attachment F demonstrate the conservatism that was used la determining the above probabilities.
The combination of the quantitative evaluation and the realistic qualitative arguments concerning exposure risk, brings the probability of occurrences of uninhabitable conditions within the limits as defined by ReOulatoly Gu!de 1.70 and NUREG-0800.
Considerir,g the analyses performed, the probabilities of occurrence of these events are such that they should not be considered as design basis events for the purpose o' evaluating control room habitability.
Commonwealth Edison will take the follow a additional steps to ensurc.nat the deletion'of the chlorine and sulfur dioxide isolatio iunctions from the Technical Specifications will not be a significant risk to the operation of the station:
1.
Upon approval of the proposed amendment, Commonwealth Edison will
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commit to maintaining the alarm function (s) of the chlorine and sulfur dioxide detectors and remove only the isolation actuation function.
2.
Agreement (s) with the local emergency preparedness agencies will be made to notify Commonwealth Edison in the event of a threatening chemical spill.
3.
A triennial survey of chlorine and sulfur dioxide shipaing and storage pattems will be conducted to verify that significant caanges have not affected the analysis.for control room hab tability.
The Commonwealth Edison control room operators have available self-contained breathing apparatuses and an air tank source of breathing air cupplied by a manifold system. The Commonwealth Edison chlorine and ( JIfur dioxide high concentration alarm setpoints of 1 ppm for the chlorine and sulfur dioxide monitor are well below the toxicity limits of 15 ppm for chlorine and 5 ppm for sulfur dioxide.
3 Should the need arise, protection against possible high concentrations associated with some of the low probability events are provided by the retained alarm functions, manual isolation function and alternate breathing air sources.
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- Proposeg_ Chug.e 1.b and 2 (DPR 30 onlyP The change of " streamline" to "steamline" is the correction of a typographical error, and as such is an administrallve change.-
Detailed Description of the Proposed Changes L
The prossed amendment to remove the isolation functions and surveillance requirements for t1e chlorine and sulfur dioxide analyzers would change Technical--
Specification 3.2.F.2 to read as follows:
"The toxic gas detection instrumentation shall cotisist of an ammonia 4
analyzer with a trip setpoint set at s 50 ppm. The provisions of Specification 3.0.A are not applicable."
The proposed amendment to correct a typographical error would change Technical Specification 3.2,F.1 to read as follows:
"The control room ventilation systeme are isolated from outside air on a -
signal of high drywell pressure, low water level, high main steamline flow,-
- high toxic gas concentration, high radiation in either of the reactor building >
- ventilation exhaust ducts, or manually. - Limiting conditions for operation shall' be as indicated in Table 3.2-1 and Specification 3.2.H and 3.2.F.2."
The proposed amendment to remove the chlorine and sulfur dioxide analyzers from-Table 4.2-1, Control Room Ventilation System, to read as' follows: -
"4. Toxic gas analyzer (ammonia) i l
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