ML20059A621

Responds to 900717 Request for Info Re Rev of Emergency Action Level for Loss of Pool Water to 15 Ft Below Pool Curb.No Member of Public Would Receive Whole Body Exposure in Unlikely Event That Pool Water Lost

ML20059A621
Person / Time
Site:	University of Wisconsin
Issue date:	08/07/1990
From:	Cashwell R WISCONSIN, UNIV. OF, MADISON, WI
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9008230136
Download: ML20059A621 (2)

Text

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4 w. ,. UniversityLof Wisconsin I 1 uctrlR atACTpR LAnonAtoRy / .

ADDRESS

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J,( ? J ocPANfMEN+ OF NUCLFam CNGWEERM AND ENOWEERGG PMWCS MECMANICAL ENOWEERWO BUILDING 'd PHONE ($04) 262-3392 .

1513 UNIVFRSITY AVENVE

. MADt%ON S370s-1512 -

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i August'7, 1990i j W

l U.S. Nuclear Regulatory Commission )

. Document. Control Desk j,- l Washington,'DC 20555 RE: Docket 50-156

ATTENTION: Theodore S. Michaels, Senior Project Manager. /

Subject:

^ Emergency Plan Review: Response to 17 July request j for information.

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Dear Sir:

ITho: revision o'f the Emergency Action-Level for loss of pool water

'to 15 feet below the pool curb was based on Technical Specification 5.7. Dose in occupied unrestricted areas is not- ,

significantly affected by a water loss to 15 feet below the pool.  ? f, curb , since the biological shield design interposes four to eight foet'of' concrete plus 3 to 5 feet of water shielding-between the. core a'nd unrestricted areas even with the' water this a far.below the pool curb. Essentially the same shielding provided  !

ffor i full' power operation provides protection to the public during

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q the pool water loss considered.  !

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'JIt is possible.that scattered radiation could cause an increase j Lin; dose, so-the following measurements and calculations are- l j

iprovided for yourl consideration. In the following. discussion'it j

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is assumed the reactor is shut down one hour before the pool water-drops to 15. feet below the pool curb. This is a realistic-l

' assumption, since the only credible means of draining the water -i more. rapidly would be through a sheared beam port with its l foutside flange removed. -ALARA and operating. procedure 2

? considerations require that beam. port outer flanges remain: sealed j 4

< .during:all conditions except installation or-removal of in-port -

portions of experiments (to control Ar-41 release).- In addition, a 1 LALARA-considerations and operating procedures prohibit experiment installation or removal'while the reactor is in operation. l l i

? Based on. measurements of dose rate directly above the reactor- ,

core at 15. feet below the pool curb from 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> after

-chutdown from a full power run, the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> dose at the pool curb would be 219 milirem. Total dose-at the roactor laboratory roof

'immediately above the pool would be 120 mrem during the same 24- .

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' Letter to U.S. NRC, Theodore's. Michaels-

- August 7,: - 1990'  ;

'Page'Two

'k P hour period if no c.ttenuation by roof structure is considered.

Based.on extremely conservative scattering calculations, the scattered dose at the nearest occupied unrestricted area would be fless than 0.1' mrem during the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period.  ;

our conclusion is that no member of the public would be receive a whole body exposure in excess of 15 milirem in the extremely unlikely' event'that pool water is lost to the proposed Emergency Action ~ Level.

Sincerely, o 4

R.J. Cashwell Reactor Director ,

RJC/cke.

c: Region III Office >

Reactor Safety Committee NEEP Department Chairman 1

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