ML20032C766
| ML20032C766 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 10/30/1981 |
| From: | Lempges T NIAGARA MOHAWK POWER CORP. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NMP-3817, NUDOCS 8111110689 | |
| Download: ML20032C766 (4) | |
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NIAGARA MOH AWK POWER CORPORATION NI AG AR A MOHAWK 300 ERf E BOULEV ARD W EST SYRACUSE.N Y.13202 Cetobe,t 30, 1981 Mt. Rcnald C. Haynes, DLtector UntLted States Nacecat Regulato.ty Comm.
Region 1 631 Pad Avenue King of Ptussia, PA 19406 Re:
Occhet No. 50-220 Dea 1 M1. Harpics,
On July 8-9, 1981, af tet fout montits of,tefueling outage and duting stattup, a conttolled disciuttge of liquid.tadioactive uttste into Lake Ontario totitling 5.3 cttties occurted at the Nine Mile Point Uitlt #1 genetating f acility.
Enclosed hetein, in compliance teitti Envitonmental Technical Specification 2.4.1.h, is a,teport detitiling (I) the causcs of the telease and (II) actions taken to.teduce the f tequency and magnLtude of futaic,tefcases.
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" '/[' 2-t Thomas E. {cmpges Vice P.icsident Nuctent Generation TEL/jb/jm Enclosu tes db$1l xy _ _ '
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CNJSES OF Tile RELEASE 1he 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 e
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facility during the first week of July 1981 exceeded the storage capacity of the system and the processing capabilities of the Waste Concentrator.
- 11 and #12 Floo-Drain Sample Tanks, the Floor Drain Collector Tank, the Waste Neutrali:er Tank and the Waste Surge Tank were all filled or nearly filled with high con-ductivity liquid waste.
2)
The performance of the Radwaste demineralizer was ' inex-pectedly poor during the latter part of the outage, resulting in considerabic downtime, frequent resin i
regenerations and a backlog of " clean waste" (ie, radio-active liquid waste with a conductivity less than 20 mhos/cm).
3) 1he 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 regener5tions.
4)
The cation tank lateral network, an integral part of the resin regeneration systeta, was readjusted during the outage end required about one week downtime. This further reduced th'e frequency of pennissible Radwaste demineralizer regen-erations and the associated processing of equipment drain waters.
5)
Cross contamination of equipment drain sumps in Radwaste Building 229' elevation with high conductivity floor drain -
filter sludge waters from Radwaste 225' elevation was immi-nent unless prompt action was taken.
In response to the backlog of Radwaste waters noted nbove, several actions, including liquid vaste discharge to Lake Ontario, were evalu-ated.
To prepare for a potential discharge, the 50,000 gallon Waste Surge Tank (on a continuous recirculation mode) was sampled and isotopi-cally analy:cd on July 7, 1981.
Finally, on July 8, 1981, condition #5 noted above dictated no alternative recourse and the discharge commenced.
Pertinent data associated with the release is listed on Table #1.
The discharge conformed with all 10CFR20 and Environmental Technical Specifi-cation limits regarding nuclide concentrations and quantities.
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II.
ACTION PLAN Nine Mile Point #1 has made a conscious effort in recent years to limit the discharge of liquid radioactive waste into Lake Ontario.
For exampic, 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, rep-sents only about 12$. of the design objective release goal of 5 curies /,sar (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 10CFR50 ALARA concept and reduce the frequency and magnitude of future liquid radioactive discharges.
1)
The processing of filter sludge material through a newly installed phase separator thereby reducing concentrator inputs (**).
2)
The procurement of two large capacity, semi-portable, standby domineralizers for use during Radwaste demineral-i:ers downtimes (if necessary).
(***)
3)
The installation of an additional 15gpm evaporator for the processing of high conductivity waste.
(**)
4)
Replacement of the Waste 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.
(*)
1 TABLE 1 Tank Discharge Rate (gpm) 30 Dilution Water Flow (gpm) 2.1125 Batch MPC (pCi/ml) 1.9E-5 Activity Concentration in Discharge Canal (pCi/ml) 7.4E-6
% MPC in Discharge Canal 39 i
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