ML20056E260

Forwards Nonproprietary & Proprietary Version of Analysis of Potential Blast Effects on LACBWR Reactor Bldg Due to 16 Inch Natural Gas Pipeline Failure,Suppl Analysis for Fast Closing Valve. Proprietary Version Withheld

ML20056E260
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	08/12/1993
From:	Berg W DAIRYLAND POWER COOPERATIVE
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19310D623	List: ML20056E260 ML20056E262 ML20056E263 ML20056E268
References
LAC-13288, NUDOCS 9308230091
Download: ML20056E260 (5)

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C@FERATIVE. 3200 EAST AVE. SO.. P.O. BOX 817 - LA CROSSE. WISCONSIN 546 (608) 788-4000 FAX NO. (608) 787-1420 iWILLIAM'L BERG -

! Gcneral Manager -

August 12, 1993

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In reply, please refer to IAC-13288 DOCKET NO. 50-409 3

Document Control Desk U. S, Nuclear Regulatory Commission Washington, D. C.

20555

Centlemen:

SUBJECT:

Dairyland Power Cooperative-La Crosse Boiling Water Reactor Possession-only License No. DPR-45 Potential Effects of Natural Gas on the LACBWR Site IContains Proprietary Informationi

REFERENCES:

(1) NRC Informat.on.totice No. 91-63, " Natural Gas Hazards i

at Fort St. Vrain Nuclear Generating Station" (2). Meeting with NRC on May 18, 1993, in Bethesda n

'Dairyland Power Cooperative (DPC) is currently finalizing plans to use

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-natural gar to co-fire the coal-fired generating station-that shares a site n

with the La Crosse Boiling Water Reactor (LACBWR). Also being considered is

-a proposal to.repower the 1ACBWR turbine'with stea9 generated.from the exhaust heat of a; gas.. turbine to be installed on the' site. The approval-and

' implementation of either or both of these proposals would include the routing of a natural gas pipeline onto and across portions of the LACBWR site. ;1n'an.

internal response to the notice of Reference 1. DPC committed to performing a safety-analysis in the event natural gas was introduced to the. site. There-fore, DPC has engaged'a contractor-(Westinghouse Electric: Corporation) to-

-perform a hazards analysis-(Attachments 1 & 2) of the potential. effects on f

the_LACBWR reactor building of postulated accidents involving a natural gas release and subsequent detonation. This gas hazards analysis, combined with the reactor building scructural analysis (Attachment 3)..'has led DPC to conclude that introducing natural gas to the-LACBWR site poses no threat to

the safety of the irradiated fuel assedlies stored in the reactor building.

i Some of the information included-in.the Westinghouse analysis is proprietary g

-and,'therefore, enclosed are:

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^ Two copies of " Analysis of the Potential' Blast Effects on the.

.lACBUR Reactor Building due to a,16-inch Natural Gas Pipeline; f

y, Failure" ' (Proprietary), and '

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Document Control Desk LAC-13288 Fagt 2 August 12, 1993

= Two copies of " Analysis of the Potential Blast Effects on the LACBWR Reactor Building due to a 16-inch Natural Gas Pipeline Failure" (Non-Proprietary).

Also enclosed are a Westinghouse authorization letter (CAW-93-461),

accompanying affidavit, Proprietary Information Notice, and Copyright Notice.

Since Attachment 1 contains information prcnrier.cy to Westinghouse Electric Corporation, it is supported by an afi'

. signed by Westinghouse, the owner of the information. The affidavit sets. th the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.790 of the Commission's regulations.

Accordingly, it is respectfully requested that the informatior. which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR Section 2.790 of the Commission's regulations.

Correspondence with respect to the copyright or proprietary aspects of the items listed above or the supporting Westinghouse Affidavit should reference CAW-93-461 and should be addressed to N. J. Liparulo, Manager of Nuclear Safety & Regulatory Activities, Westinghouse Electric Corporation, P.O. Box 355, Pittsburgh, Pennsylvania 15230-0355.

In addition to the " worst case" gas release and subsequent detonation analysis, DPC will have automatic and administrative controls established, prior to the introduction of natural gas to the site, that will mitigate the effects of any gas leak on site.

These controls will include:

(1) Automatic closure (with manual backup) of dampers on the Reactor Building, Turbine Building, 1B Diesel Generator Bui.lding, Control Room and, if applicable, any newly constructed Heat Recovery Steam Generator Building.

(2) Automatic shutdown (with manual backup) of the Stack fan (s) to reduce or eliminate any negative pressure in Reactor, Turbine, and Waste Disposal Buildings.

(3) Automatic closure of gas line isolation valve at site boundary on a pressure signal indicating a gas line rupture.

(4) Manual closure of gas line isolation valve upon receipt of indication of any significant leakage of gas from the supply line.

(5) Routine operability checks of the varicas systems required to perform the above mitigation actions.

(6) The routin of the pipeline on the site will be identified and o

signs will be pested to prevent digging in the area of the pipeline.

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Document Control Desk

. LAC-13288 Page 3

. August 12, 1993 l

In the meeting of Reference 2, several additional-issues were raised j

that required analysis. The following questions were asked and the responses to them follow:

(1) How would gas be prevented from entering those structures of greatest concern (reactor building and turbine building) through electrical wiring conduits?

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RESPONSE

DPC will seal the cable tray entering the turbine building at the west end that carries cables from the area of the gas pipeline. The reactor building cables are already sealed.

(2) How would gas be prevented from entering tnese buildings through drain lines that communicate to the outside of the building (s)?

RESPONSE

The only drain that exits the turbine building, and is vented to the a tmosphere in the area of the gas pipeline, will have a trap added to seal it or it will be removed.

(3) What would be the consequence (s) of any of the buildings that don't have automatic ventilation isolation ingesting gas and exploding?

RESPONSE

Other buildings on the site that could ingest gas due to their proximity l

to the gas line are the warehouses, the maintenance lunchroom, the administration building, and the crib houses for the two plants.

(See attached site layout drawing.) The locations of these buildings are such that any projectiles generated from an explosion of any of them would have to travel through other buildings and/or 1.16" of steel and, at least, several feet of concrete to reach the spent fuel storage pool' because of the pool being located on the south side of the containment building.

The other buildings which could have gas in them are the Genoa #3 power plant which will be overfiring with gas and the gas turbine building, if repowering of LACBWR occurs.

There will be administrative controls in place as well as automatic actions to prevent gas from accumulating in l

these buildings.

Pressure sensors will cause automatic closure of isolation valves at the entrance of the gas line to the building (s).

Also, personnel routinely patrolling these buildings will be instructed to notify the control room (s) if a leak is apparent and the valve (s) will be closed, a

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3 Document Control Desk LAC-13288 Page 4 l

August 12, 1993 h

There are several.other buildings on the site (waste disposal building, warehouses, guard house) that are far enough from the gas line that they wouldn't be affected by a leak because of the buoyance of the gas.

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gas would rise above them before it reached any doors, windows, or ventilation intakes.

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One othet question was raised by the LACBWR Safety Review committee when discussing site structures. The question of the LACBWR stack and its potential for withstanding a gas detonation was discussed. This issue will i

be addressed when the final site configuration is decided and appropriate l

i action will be taken if the analyses shows it to be necessary.

If, for example, the only project completed is the co-firing of the coal plant, the plans for the site would include a much smaller gas line (6" vs. 16" if LACBWR is repowered) and a lower gas line pressure. This scenario would, of course, provide much less potential for gas accumulation and detonation of

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the size that could damage the stack.

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I It should be noted that a study was done at the time of the i sittal of the LACBWR Decommissioning Plan showing that in the worst-case accident possible in the current SAFSTOR condition (cask drop into Fuel Element Storage Pool), a 10 CFR Fart 100 release was not possible because of the i

small inventory of radioactive nuclides.

Since then, the spent fuel has l

undergone more than 5 years of further decay.

(See Attachment 4 for a detailed discussion of the spent fuel and radionuclide inventory.)

i The results of the " worst case" gas release analysis, combined with the Reactor Building Structural Analysis and the mitigation equipment and procedures has led DPC to conclude that introducing natural gas to the LACBWR i

site poses no threat to the safety of the stored fuel.

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if you have any questions, please call John Parkyn at (608) 689-2331.

l Sincerely, DAIRYLAND POWER COOPERATIVE 5

$AW b Af WilliamL. Berg, Gen (eralManager WLB: REC:dh i

Attachments r

i ec:

A. Bert Davis, Regional Administrator U. S. Nuclear Regulatory Commission, Region Ill Clen Ellyn, IL 60137 Larry Pittiglio, Project Manager Division of Nuclear Materials Safety & Safeguards U. S. Nuclear Regulatory Commission l

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ATTACHMENT 2

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