ML20125B303

Discusses Util Request to Modify off-gas Sys by Adding Recombiner,Compressors & Pressurized Holdup Tanks to Provide Min of 50 Hours.Aec Cannot Conclude That Releases from Plant Alap

ML20125B303
Person / Time
Site:	Monticello
Issue date:	05/19/1971
From:	Thomasson W US ATOMIC ENERGY COMMISSION (AEC)
To:	Grill R US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9212090297
Download: ML20125B303 (1)

Text

. - .. _

UNITED STATES

, ATOMIC ENERGY COMMISSION

)b 1

1 ~4* l WA$mNGTON, O C. 20$4 May 19,1971 R. P. Grill, Chief, Site Safety Branch, DRL M0KTICELLO NUCLEAR GENERATING PLANT E-5979, DOCKET NO. 50-263 -

PROPOSED CHANGE IN GASEOUS RADWASTE SYSTEM AND TEGINICAL SPECIFICATIONS

-- MEETING SU MARY The applicant has proposed to modify the Monticello off-gas system (presently with 30 minutes holdup) by adding a recombiner, compressors and pressurized holdup tanks to provide a mininum holdup of 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />.

%is would provide an over 11 decontamination factor of approximately 22 and 125 for curies and doses (beta-gamma) respectively. It is the applicant's design objective to reduce the air ejector releases to 0.012 Ci/sec from 0.27 Ci/sec which would yield whole body dose of 4 mren/ year. Ilowever, in evaluating the releases from the facility, only the air ejector discharge has been considered. We informed the applicant that-we could not conclude that the releases from Monticello were as " low as practicable."

We indicated that, in our view, this was a new facility (including a building and equipment) and it must be designed against applicable natural phenomenon criteria as presently established by the Commission. %e applicant finally committed to designing the building and equipment against the effects of the Probable Maximum Flood, the Design Basis

, Earthquake and the design tornado. However, the intended location of the new facility will be at the base of the existing plant stack, which, although, Class I seismicall;, is not designed to withstand the design tornado. On this account, we will use 10 CFR 20 as the appropriate guide to evaluate accident consequences. %e applicant's analyses of the whole body dose for the release of all stored noble gases yields a dose of 0.8 res.

We other major deficiency in the applicant's evaluation is- that there has been no evaluation of iodine releases (accident or routine) since they contend that most, if not all, of the iodine will be removed by the recombiner. Here is no data on this removal mechanism, however, nor do they intend to perform RSD on it. Other points raised by the staff on system design, performance, and R6D such as catalyst poisoning, will be covered by the project leader, Vic Benaroya.

(

UMM W. N. Thomasson, Site Safety Branch .

Division of Reactor Licensing l cc: }l, Denton SSRS Menbers 9212090297 710519 S(8 PDR ADOCK 05000263 ,

p PDR

-. . . - _ _ _