ML20248J852

Special Rept:On 890302,projected Doses Due to Radioactive Liquid Effluents Discharged to Unrestricted Areas Exceeded 0.06 Mrem Total Body in 31 Day Period.Caused by Calculation Error.Radiological Effluent Tech Specs to Be Computerized

ML20248J852
Person / Time
Site:	North Anna
Issue date:	04/07/1989
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
89-246, NUDOCS 8904170113
Download: ML20248J852 (3)

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VINGINIA ELECTRIC AND PowEn COMPANY Hrcuxown, VIRGINIA 20261 w.n.ciarwn:.,"'

Vaca Pansanant April 7, 1989 Nocs.sau f

-United States Nuclear Regulatory Commission Serial No.89-246

' Attention: Document Control Desk NAPS /JHL Washington, D. C. 20555 Docket Nos. 50-338 50-339 License Nos.-NPF-4 NPF-7 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2

.SPECIAL REPORT - RADI0 ACTIVE EFFLUENTS EXCEED TECHNICAL SPECIFICATION LIMITS At 1928 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.33604e-4 months <br /> on March 2,1989, with Units 1 and 2 in Mode 5, projected doses r

due to radioactive liquid e fluents discharged to unrestricted areas, exceeded-the 0.06 mrem total bo4 in a 31 day period (per unit) limit of Technical Specification 3.11.1.3. With radioactive waste being discharged without treatment and with projected doses in excess of the Technical Specification limits, TS 3.11.1.3 requires the licensee to prepare and submit a Special Report to the Commission, within 30 ' days, pursuant to Specification 6.9.2.

The Special Report shall include: 1) an explanation of why liquid radwaste was being discharged without treatment, identification of any inoperable equipment or subsystems, and the reason for inoperability, 2) action taken to restore the inoperable equipment to operable status, and 3) a summary description of action taken to prevent recurrence, i

The cause for discharging liquid radwaste (without clarifier demineralized treatment), when dose projections were in excess of Technical Specification 3.11.1.3 limits, was due to a calculational error made while performing Health Physics procedure HP-7.3A.22. Personnel inadvertently recorded the concentrations of the liquid radwaste discharged instead of the activity )

released for the dose calculation. This calculational error resulted in low projected dose values. Consequently, liquid radwaste was discharged without being processed through the final demineralized system stage located in the

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1 Clarifier Building from February 20, 1989 to March 2, 1989. The high level i liquid waste processing system was fully operational throughout this event and high level liquid waste was demineralized before being discharged to the lj clarifier system.

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. l In addition, at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on March 8, 1989, with Units 1 and 2 in Mode 5, in accordance with Offsite Dose Calculation Manual (0DCM), the calculated quarterly dose to the maximum exposed member of the public from radioactive j materials released to unrestricted areas apparently exceeded the Technical  ;

Specification 3.11.1.2.a limit of less than or equal to 1.5 mrem total body [

(per unit, 3 mrem total body per site). Technical Specification 3.11.1.2 requires that with the calculated dose from the release of radioactive materials in liquid effluents in excess of the Technical Specification limits, prepare and submit to the Commission within 30 days, pursuant to Specification 6.9.2, a Special Report that identifies the cause(s) for exceeding the i limit (s) and defines the corrective actions that have been taken to reduce the j' releases and the proposed corrective actions to be taken to assure that subsequent releases will be in compliance with the Technical Specification l limits, i

Conservatism in the ODCM M :ulation methodology during low circulating water flow rates resulted in a calculated quarterly dose to the maximum exposed number of the public to apparently exceed the Technical Specification limit of 3 mrem. This resulted (as of March 8, 1989) in a calculated release of:

Total Body Dose: 3.79E0 mrem l Critical Organ Dose: 5.30E0 mrem Revised calculations taking low circulation water flow rates into account and ,

using end of quarter data resulted in: l Total Body Dose: 2.02E0 mrem Critical Organ Dose: 2.81E0 mrem i i

These results indicate that the limits of Technical Specification 3.11.1.2 I were nct exceeded during the first quarter of 1989.

To prevent recurrence of this event, the Radiological Effluent Technical Specifications (RETS) will be computerized. Dose projection calculations to support bypassing the Liquid Radwaste Ion Exchanger System will be 1 independently verified. Approval to bypass the Liquid Radwaste Ion Exchanger

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System will only be given if the results of both calculations agree and are l below Technical Specification limits. Implementation of the computerized RETS  !

will enable trending of doses from liquid effluents on a short term basis. In '

the interim, short term trending of liquid pathway doses will be initiated if i a Cesium 134 or Cesium 137 concentration of 1.0E-6 uCi/ml or greater are detected in liquid effluents. The ODCM and Health Physics procedures will be revised to account for low circulating water flow rates, and to trend doses at short time intervals to determine if there is a substantial increase in relation to the Technical Specification limit.

These events posed no significant safety implications because Technical Specification 3.11.1.2 limits were not exceeded and the concentration of radioactive effluents released to the unrestricted area were well below 10CFR20 limits. The health and safety of the general public were not affected ,

during this event.

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• 4 Due to an administrative error, this Special Report was not submitted to the Commission within the specified 30 days. This error was discussed with the NRC Project Manager where we informed him that the Special Report would be submitted by April 7,1989. We have reviewed our correspondence tracking system and have taken appropriate actions to assure that adequate controls have been put in place to prevent recurrence of this error.

Very truly yours, Sh

. R. Cartwright cc: U. S. Nuclear Regulatory Commission 101 Marietta Street, N. W.

Suite 2900 Atlanta, Georgia 30323 Mr. J. L. Caldwell NRC Senior Resident Inspector North Anna Power Station l

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