ML20086P667

Nonroutine Radiological Environ Operating Rept Re Review of Observed Levels of Ag-110m in Oyster Samples Collected During 1983.Caused by Tendency of Oysters to Highly Bioconcentrate Environ Silver

ML20086P667
Person / Time
Site:	Calvert Cliffs
Issue date:	01/17/1984
From:	Fuhrman G BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 8402270285
Download: ML20086P667 (3)

Text

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BALTIMORE GAS AhH3 ELECTRIC CHARLES CENTER. P.O. BOX 1475. ' BALTIMORE, MARYLAND 21203 ELECTRIC ENGINEERING D EPARTM ENT January 17, 1984 The Regional Administrator U.S. NRC Region 1 631 Park Avenue King of Prussia, PA 19406

Subject:

Calvert Cliffs Nuclear Power Plant Unit Nos. 1 and 2 License Nos. DPR-53 and 69 Nontoutine Radiological Environmental Operation Report This report is submitted in compliance with the requirements of Appendix B Environmental Technical Specification Sectio'n 5.6.2.b, with a review of the observed levels of Ag-110m in Oyster samples collected during 1983.

In addition, we are providing an estimate of the potential dose commitment based on the mean value of Ag-110m in' oyster samples for 1983.

Oyster samples were collected during December, 1983 from the Camp Conoy sampling location, and analyzed for gamma-emitting radio-nuclides as required.

The results of the analyses showed the presence of Ag-110m with a concentration of 113 + 6 pCi/Kg (wet).

The oyster samples collected during the same period from the Kenwood Beach sampling location (the background location) showed a Ag-110m concenttation of

< 8. pCi/Kg (wet).

The release rate of radioactive effluents during the period of interest was well within the allowable release limit specified in the Environmental Technical Specification (ETS) Section 2.3 Liquid Effluents, Specification A.7.

The maximum concentration of Ag-110m, in the effluent prior to discharge into the Bay, was less than 0.002%

of the limit specified in 10 CFR Part 20, Appendix B, for unrestricted

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,The Regional Administrator January 17, 1984 Oysters have a na'_ ural tendency to highly bloconcentrate environmental silver.

As a result of this bioconcentration, oyster cuscle tissue show radioactive silver as observed in samples collected durind 1983.

These levels are reportable ~on the basis of the Calvert

, Cliffs ETS exceedance criterion which is " ten times the back' ground",

where " background" is the " minimum detectable concentration" in the control sample.

For the period of interest in 1983, the monthly percent capacity factors for botn Units were as follows:

Period Unit 1 Unit 2 Nov. 1983 0

79.21%

De,c. 1983 51.10%

39.05%

The Calvert Cliffs Unit 1 was shut down on October 1, 1933 for planned maintenance work; namely, a genecal inspection / maintenance end refueling.

Following completion of this planned maintenance work, Unit I was brought back c.rline on December 10, 1983.

The processed radwaste, from the combined waste processing system for Units 1 and 2, was released into the 'cf rculating water prior to discharge into the Bay.

The radwaste may be released at a design

~ rate that can range from 10 GPM 'o a maximum of 120 GPM.

In practice, the releases are made at a predetermined rate depending upon the measured concentration of radionuclides in the radwaste, the ETS limits, cs well as the established ALARA objectives.

Using the circulating-water-pump data for the period of interest, it is estimated that at the maximum release rate, the radgaste concentration is decreased at least by a factor of about 1 x 10 prior to discharge into the Bay.

Based on the Ag-110m concentration observed in oyster samples, tne potential total dose commitment to the Gl-Tract and tne Whole Body of a maximum exposed individual (with the consumption rate of 5 kilo-gram / year and the dose conversion factors as recommended in Reg. Guide 1.109, Rev.

1, Oct is estimated at less than 0.04 mrem and less than 0.5 x 10'gber 1977) mrem, respectively.

During 1983, the observed; levels of Ag-110m in oyster samples

-collected from the_ oyster bars at Camp Conoy ranged from 113 + 6 to 535 + 15 pCi/Kg (wet), with a mean value of 283 1 169 (at one sigma) pCi/Kg (wet).

Based on this mean value, the potential dose commitment to the GI-Tract and the whole Body of a maximum exposed individual (with the comsumption rate of 5 kilogram / year and the dose conversion factorn as recommended in Reg. Guide 1.109 Rev. 1, Octo 1977) is less'than0.1mremandlessthan0.15x1[ger I

cstimated at

mrem, respectively.

These doses are small fractions of the permissible limit of 25 mrem / year to members of the general public as set forth in 40 CFR Part 190 " Environmental Radiation Protection Standards for Nuclear

.The Regional Administrator January 17,~1984 Power Operations",-and are therefore considere'd to be of insignificant consequence to the health and safety of the public.

Very tr ly

ours, Ga R.

Fuhrman, Director Environmental Programs

. GRF/f ew cc:

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

20555 Dr. Randy A. Roig Power Plant Siting Program State of Maryland Tawes State Office Building Annapolis, MD 21401 Mr. R.

E. Architzel NRC Resident Inspector Calvert Cliffs

_.