ML18037A365

Forwards Rept Detailing Causes of 810708-09 Release of 5.3 Ci Liquid Radwaste Into Lake Ontario.Actions Taken to Reduce Frequency & Magnitude of Future Releases Discussed

ML18037A365
Person / Time
Site:	Nine Mile Point
Issue date:	10/30/1981
From:	Lempges T NIAGARA MOHAWK POWER CORP.
To:	Office of Nuclear Reactor Regulation
References
NMP-3818, NUDOCS 8111040298
Download: ML18037A365 (10)

Text

REGULATORY r rORMATION DISTRIBUTION SYSTEM (RIDGED ACCESSIOV< NBR:8111040298 DOC,DATEi 81/10/30 NOTARIZED NO DOCKE~T' FACILt:50'-220 Nine -Rile Point Nuclear Station~ Unit 1r Niagara'owe 05000220

'AUTHl. N <ME. AUTHOR AFFILIATION LEMPGES~,T.EI, Niagpra~ Mohawk[ Power~ Corp.

REC IP ~ VAMEI REC~IPSENT AFF ILIAD'IOiV Of f i cel of Nuclear Reactor Regu1 at i oneDire'c ter i

SUBJECT:

-'orwards reot detail ing. causes of 810708-09=- release of 5o3 Ci liquid r adwaste into Lakei Ontario, Actions taken< to reducel f requency I magni tude of futur ei r el eases di scusse'd; DISTRIBUTION CODEi: C001S COPXEG RECEa VED:Ltt'R ENCL SIZE:-

TKTLEt Ehv ir on, Report Amendments 8 Rel ated Correspondence,'OTES':

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TOTAL NU4iBER< OF COPIES REQUIRED: LiTTR 20 ENCL< 19

NMP-9818 NIAGARA MOHAWK POWER CORPORATION NIAGARA "~ MOHAWK 300 ERIE BOULEVARD. WEST SYRACUSE. N. Y. 13202 NAectolt, NOVO 3 tga~l 1O O)gce o$ Nuclettlt, Revolt. Regulate.on Millt%KLha E20tl~g~

'United S~m Nuclealt. Regulatolty Comm. r ~@gg Nasfungkon, OC 20555 II Re,: OockW No. 50-220 gee. Zvt,,

On July 8-9, 1981, a(Celt. (ottlt mod@ o( lte$ ueXing outage and ckuu.ng a~p, a contltolled d&chaltge o$ ~tw.d ltatLt',oa~ve uIatICe ~nto Lake, Onkuu.o Co~ng 5.9 nuu'.el occttltlted at Che N~ne NLe P m U~ <1 generating I%any. Enclosed heltein,L n commence ~h ~u Environmental Tech.cal Speci (4'cation 2.4.1. h, Le a ltepoM deta~ng (I) Ae o$

4he lteleaee and (II) a~eh Wken Co lteduce Che $ ltequency and magnitude o$ JLtulte lt.eleaseg .

Mncelt.ely, Vie; Pltukdent Nuclealt. 'Gen~on TEL/jb/jm Encloattlt.el 0'I II g Sl I 040298 811030 PDR ADOCK S 05000220

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CAUSES OF THE RELEASE The following .conditions directly or indirectly necessitated the release of liquid radioactive waste into Lake Ontario in July 1981:

,1) The influx of floor drain waters into the Radwaste facility during the first week of July 1981 exceeded the storage capacity of the system and the processing capabilities of the Naste Concentrator. ¹11 and ¹12 Floor Drain Sample Tanks, the Floor Drain Collector the Naste Neutralizer Tank and the Naste Surge 'ank, Tank were all filled or nearly filled with high con-ductivity liquid waste.

2), The performance of the Radwaste demineralizer was unex-pectedly poor during the latter part of the outage, resulting in considerable downtime, frequent resin regenerations and a backlog of "clean waste" (ie, radio-active liquid waste with a conductivity less than 20pmhos/cm).

3) The 'processing of approximately 500,000 gallons of torus water in the early part of the outage yielded a high in-ventory of filter sludge and necessitated additional resin regenerations.

4) The cation tank lateral network, an integral part of the resin regeneration system, was -readjusted during the outage and required about one week downtime. This further reduced'he frequency of permissible Radwaste demineralizer regen-erations and the associated processing of equipment drain waters.

5) Cross contamination of equipment drain sumps in Radwaste Building 229'levation with high conductivity floor drain-filter sludge waters from Radwaste 225'levation was immi-nent unless prompt action was taken.

In response to the backlog of Radwaste waters noted above, several actions, including liquid waste discharge to Lake Ontario, were evalu-ated. To prepare for a potential discharge, the 50,000 gallon Naste Surge Tank (on a continuous recirculation mode) was sampled and isotopi-cally analyzed on July 7, 1981. Finally, on July 8, 1981, condition ¹5 noted above dictated no alternative recourse and the discharge commenced..

Pertinent data associated with the release is listed on Table ¹1. The discharge conformed with all 10CFR20 and Environmental Technical Specifi-cation limits regarding nuclide concentrations and quantities.

'll. ACTION PLAN Nine blile Point tl .has made a conscious effort in recent years to,limit the discharge of liquid radioactive waste into Lake Ontario. For example, in the 42 month period between late 1977 and July 1981, less than 2 curies of liquid waste was discharged. This value, on the average, represents only. about 12'f the design objective release goal of 5 curies/year (Environmental Technical Specifications - Section 2.'4).

Despite present capabilities to stay well within 10CFR20 and design ob-jective discharge, limitations during normal operation, several measures are now under consideration (*), planned for implementation (**) or already being implemented (***); which should further enhance the station's commit-ment toward the 10CFRSO ALARA concept and reduce the frequency and magnitude of future liquid radioactive discharges.

1) The processing of filter,sludge material through a -newly j installed phase separator thereby reducing concentrator

-inputs (**). f II

2) The procurement of two 3.arge capacity, semi-portable,

.standby demineralizers Xor use during Radwaste demineral-

'izers downtimes,(iS necessary). (*"*)

3) The installation of an additional 15gpm evaporator for the processing of high conductivity waste. (**)

,4) ,Replacement of the ifaste Surge Tank with a new tank of larger capacity. (*)

5) The installation of either or both an additional storage tank and an additional demineralizer in the Radwaste Com-plex. (*)

0 I ~ P TABL'E 1 Tank Discharge Rate (gpm) 30 Dilution Water Flow (gpm) 2.11E5 Batch MPC (pCi/ml) 1.9E-5 Activity Concentration in Discharge Canal (gCi/ml) 7. 4E-6

~~ MPC in Discharge Canal