ML20212N770

Application for Amends to Licenses NPF-11 & NPF-18,removing All Refs to Ammonia Detector Monitoring Instrument Sys

ML20212N770
Person / Time
Site:	LaSalle
Issue date:	03/06/1987
From:	Allen C COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20212N774	List: ML20212N770 ML20212N785 ML20212N811
References
2814K, NUDOCS 8703130147
Download: ML20212N770 (7)

Text

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/ Commonwealth Edloon 4 } One First Nat onal Plaza. Chcago, Illinois (s

• 2 Address Reply to: Post Omco Box 767

\/ Chcago, Illinois 60690 - 0767 March 6, 1987 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington,-D.C. 20555

Subject:

LaSalle County Station Units 1 and 2 Proposed Technical Specification for Facility Operating License NPF-ll and NPF Ammonia Detection System NRC Docket Nos. 50-373 and 50-374 References (a): Regulatory Guide 1.78, Revision 0, June 1974,

" 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 for Nuclear Power Plants."

(c): UPSAR Table 2.2-3, Industries with Hazardous Materials within 10 Miles of the site.

(d): 10 CFR Part 50.72, "Immediate Notification Requirements of Significant Events at Operating Nuclear Power Plants.

(e): 10 CFR Part 50.73, " Licensee Event Report System."

Dear Sir:

Pursuant to 10 CFR 50.90, Commonwealth Edison proposes to amend Appendix A, Technical Specification, to Facility Operating License NPP-ll and NPF-18. This document change is being submitted for your staff's review and approval. This change removes all references to the ammonia detector monitoring instrument system. We believe this system is not required at LaSalle as the toxic hazard created by the accident release of ammonia is not a significant risk to the safe operation of the station.

Attachment A provides background and discussion. The proposed revised Technical Specification page changes are enclosed in Attachment B. The i attached change has received both on-Site and Off-Site review and approval.

We have reviewed this amendment request and find that no significant hazards consideration exists. This review is documented in Attachment C.

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.o March 6, 1987 US NRC Commonwealth Edison is notifying the State of Illinois of our request for this amendment by transmitting a copy of this letter and its attachments to the designated State Official.

In accordance with the requirements of 10 CFR 50.170, a fee remittance in the amount of $150.00 is enclosed.

Please direct any questions you may have regarding this matter to this office.

ery truly yours, v

C. M. Allen Nuclear Licensing Administrator 1m Attachments A: Background and Discussion B: Technical Specification Change to NPF-11 and NPF-18 C: Evaluation of Significant Hazards Consideration D: Habitability of the LaSalle County Station Control Room Following Postulated Accident Involving Shipments of Anhydrous Ammonia in the Vincinity of LaSalle County Station

! cc: Region III Inspector - LSCS Dr. A. Bournia - NRR M. C. Parker - State of Ill.

Regional Administrator - RIII SUBSCRIBED AND SWORN to I

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ATTAQWENT A TECHNICAL SPECIFICATION CHANGE REQUEST LASALLE COUNTY STATION UNITS 1 AND 2 BACKGROUND AND DISCUSSION BACKGROUND Anhydrous ammonia is identified in Table C-1 of Regulatory Guide 1.78 (reference (a)) as a toxic substance which should be considered when evaluating

'the habitability of a nuclear power plant. control room during a postulated hazardous chemical release. The hazard to the control room habitability posed by a particular toxic chemical depends upon the distance the material is stored 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.

Regulatory Guide 1.78 requires that mobile or stationary sources of anhydrous ammonia within a five mile radius of the plant be included in the habitability analysis. Regulatory Guide 1.70 (reference (b), in Section 2.2,

! requires that all facilities and activities within five miles of the nuclear

! plant be considered in the analysis, and in addition it requires that facilities and activities at greater distances be considered as appropriate to their significance.

In 1975, a survey of industries and transportation routes which may use, store and/or transport hazardous chemicals in the vicinity of the LaSalle County Station was completed to meet the requirements of Regulatory Guide 1.78.

The survey indicated that anhydrous ammonia was transported in the area of the LaSalle Station and that several industries stored and/or utilized this chemical at their facilities (reference (c)). At that time, no further analysis was performed to determine whether uninhabitable conditions could be caused in the control room during an accidental release of anhydrous ammonia.

Instead, to expedite the licensing of the plant, redundant ammonia detectors were provided on each outside air intake of the control room.

In 1986 and 1987, a second set of surveys was conducted to supplement the 1975 data and to provide additional information needed to perform quantita-tive analyses of the station control room habitability and exposure risk due to accidental release of anhydrous ammonia. This survey was used as the basis for a quantitative analysis of the LaSalle Station control room habitability and exposure risk due to accidental release of anhydrous ammonia. A probability analysis considered the statistical data required to cause the development of toxic concentrations in the control room. The conclusion of

( the probability analysis serves as the basis for this submittal to remove the ammonia detector from the Technical Specifications.

DISCUSSION The revised Immediate Notific'ation and Licensee Event Report (LER) rules (references (d) and (e)) require reporting of "any event or condition that results in manual or automatic actuation of the Engineered Safety Feature (ESF)". (10 CFR 50.73(A)(2)(iv):and 10 CPR 50.72(B)(2)(ii)). The actuation logic for.the ammonia detection system is one out of two taken once logic.

Therefore, if either of the two ammonia detectors trip, the recirculation mode for the control room.(CR) and the auxiliary electric equipment room (AEER) ventilation systems is actuated. This actuation of an ESF system is reportable within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> by telephone and within 30 days in writing as required by references (d) and (e). These LERs for inadvertent actuation of an ESP reflect

. negatively in LaSalle Station's rating in the Systematic Assessment of Licensee Performance reports (SALP).

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At the present, the ammonia detectors are also a high maintenance item which require a significant number of manhours to maintain operablility.

Performance of weekly preventive maintenance tasks, functional tests, calibrations and maintenance requires an average of 48 manhours each month.

These detectors have experienced spurious trips on numerous occasions with resulting actuation of the recirculation mode for the control room and the auxiliary electric equipment room ventilation systems.

The major sources of ammonia on and off site are detailed in Attachment D. It should be noted that in addition to the sources identified in Attachment D, small amounts of reagent grade ammonium hydroxide and ammonium molybdate are used in the on-site chemistry laboratories. The small quantities of chemical involved are not considered to be a threat to the control room environment. The following is a summary of the control room habitability study for on-site and off-site transportation and storage of anhydrous ammonia:

1. Shipments of anhydrous ammonia on the nearest highways and the nearest railroad need not be considered in the control room habitability analysis,

! as they are more than 5 miles from the control room.

2. The nearest county road which is approximately 2560 feet away from the

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i control room ventilation air intake is used for the transportation of l

ammonia tanks which contain approximately 6350 pounds of ammonia. This ammonia is used as an agricultural fertilizer by the local farmers. This source was considered in the analysis. It was determined, however, that l

event under the worst case conditions the maximum calculated concentration l

in the control room, after 2 minutes from initial detection by odor, would L be 92 ppm. Since the toxic concentration for anhydrous ammonia is 100 ppm (reference (a)) this source was not included in the aggregate probability of causing inhabitable conditions in the control room by accidents involving ammonia releases.

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3. A section of the Illinois River passes within 5 miles of the station control room air intake, and the survey indicated that shipments totaling 310,500 tons by 121 barges on the Illinois River is representative of the annual barge shipments of anhydrous ammonia in the vincinity of the station. The ammonia.is shipped in specially constructed refrigerated cylinders of 1800 tons each, with two. cylinders per barge. This source was considered in the analysis.

4. Two stationary storage facilities are located near the station. The Kaiser Agricultural Chemical Company stores anhydrous ammonia in two refrigerated tanks (20,000 and 22,500 tons) which are located just outside of the 5 mile radius. The Seneca Port Authority also stores 30,000 tons of ammonia in a refrigerated tank which is approximately 5.75 miles from the plant. Even though these sources are located at distances greater than 5 miles from the plant, they were considered in the analysis as required in Regulatory Guide 1.70.

5. Commonwealth Edison is currently leasing approximately 300 acres of land l

to local farmers. At the present time the farmers are using 28% granular nitrogen to fertilize the leased property, however, the possibility of using anhydrous ammonia in the future does exist. It was assumed in the analysis that as many as 10 tanks, each carrying approximately 6350 lbs of ammonia, could be used on the leased property each year. This ammonia would be transported on the station service road which passes within 550 feet of the control room air intake. It was further assumed that one tank j

would be stored on site for a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. These sources of ammonia were considered in the analysis.

Attachment.D determined the aggregate possibility of causing uninhabi-table conditions in the control room by somming the individual probabilities of ammonia due to accidents involving ammonia barges, ammonia storage tanks and l

on-site transportation and storage of manonia. The aggregate probability was l

calculated to be 2.0E-6 per year. This probability assessment is conservative, and, when it is combined with reasonable qualitative arguments (Attachment D, Section 9.0), a more realistic exposure risk assessment of 7.25E-8 per year I can be obtained.

It has been determined that the toxic hazard created by the accidental release of ammonia in the vincinity of LaSalle County Station is not a significant risk to the safe operation of the station. Therefore, it can be concluded that the challenges to a plant safety system caused by the spurious ,

trips of the ammonia detection system are unwarranted and in fact a deterrent to the safe and economical operation of the plant.

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Based on the above discussion, it is proposed that the LaSalle county Station Units 1 and 2 Technical Specifications be revised to remove all references to the ammonia detectors (Attachment B). Upon approval of this change to the Technical Specifications, the ammonia detection system will be physically removed from the ventilation system and. references to the ammonia detection system will be removed from the Updated Final Safety Analysis Report.

The licensee will monitor ammonia shipping and storage patterns in the vicinity of LaSalle Station by performing a survey of river tratfic and local industries on a tri-annual basis. It will be verified that any significant changes in the ammonia shipping and/or storage patterns do not have a significant effect on the analysis for control room habitability. The results of this review will be included in the station annual report.

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ATTACINNT B TECHNICAL SPECIFICATION CHANGE REOUBST LASALLE COUNTY STATION UNITS 1 AND 2 PROPOSED CHANGES TO APPENDIX A REVISED PAGES:

NPP-ll NPP-18 V V 3/4 3-74 3/4 3-74 3/4 7-5 3/4 7-5 3/4 7-6 3/4 7-6 B 3/4 3-5 B 3/4 3-5 r

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