ML20235M577

Safety Evaluation Supporting Control Room Habitability Sys of Plant & Acceptability of Existing Tech Spec Re Control Room Pressurization Requirement

ML20235M577
Person / Time
Site:	Brunswick
Issue date:	02/16/1989
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20235M570	List: ML20235M567 ML20235M577
References
NUDOCS 8902280327
Download: ML20235M577 (4)

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p %y UNITED STATES NUCLEAR REGULATORY COMMISSION

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING CONTROL ROOM RADIOLOGICAL HABITABILITY CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324 INTRODUCTION By letter dated August 30,1985 (NLS-85-311), Carolina Power & Light Company (CP&L) provided an evaluation on the control room radiological habitability for the Brunswick Steam Electric Plant, Units 1 and 2 (Brunswick 1 and 2). The submittal was made.by CP&L to justify the acceptability of the existing technical specification regarding the control room pressurization requirement. The staff performed an independent evaluation of the control room radiological habitability for these facilities.

DISCUSSION During testing in June 1984, the licensee, CP&L, was unable to demonstrate the ability to pressurize the Brunswick 1 and P control room to a pressure of 1/8 inch positive pressure with the emergency control room ventilation system in operation. The licensee was able to meet the technical specification require-ment to maintain a positive pressure. The licensee reevaluated the control room radiological habitability. They assumed a flow rate of 3000 cfm unfiltered inleakage to extrapolate to the flow rate needed to produce the 1/8 inch positive pressure in the control room with the emergency control room emergency ventilation system in operation. The licensee evaluated potential consequences to operators in the control room from both the loss of coolant accident and the steam line break accident. The steam line break accident was the more limiting accident for the control room radiological habitability assessment for the Brunswick 1 and 2 control room.

The staff reviewed the CP&L analysis of the control room radiological habitability for Brunswick I and 2.

The staf.f also performed an independent assessment of the control room radiological habitability for the steam line break. The assumptions utilized by the staff's  ;

analyses are tabulateti in Tables 1 and 2. The resulting doses in the control i room, based upon the tabulated assumptions for the course of the steam line i break accident, are 19 rem to the thyroid and less than 0.1 rem to the whole body and ' skin.

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l The ddse guidelines for evaluating the control room radiation protection provisions are as follows:

Whole Body, Ganna: 5 rem Thyroid: - 30 rem Beta Skin Dose: 30 rem In accordance with GDC 19 these doses to an individual in the control room should not be exceeded for any postulated design basis acc dent.

The staff concludes that the control room habitability system of the Brunswick 1 and 2 facility is acceptable. The control room meets the requirements of GDC 19 with respect to maintaining the control room in a safe and habitable condition under accident conditions. It provides adequate protection against radiation so the radiological exposures are within the limits of this criterion. The licensee has thus demonstrated that with the pressurization test results obtained in the Brunswick 1 and 2 control room control room operators will be adequately protected.

Principal Contributor: Irwin Spickler Dated:

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f Table 1 ASSUMPTIONS USED TO EVALUATE THE MAIN STEAM LINE BREAK ACCIDENT OUTSIDE Mass of primary coolant released before main steam isolation valve closure, pounds 140,000 Fraction of iodine in the primary coolant that is ,

released, percent. 100 Fraction of noble gases released, percent 100 Primary coolant concentration, microcuries per gram Technical Specification' limit, normal short-term operation 4.0*

Technical Specification limit 100/E**

Other assumptions as in Regulatroy Guide 1.5, " Assumptions Used for Evaluating the Potential Radiological Consequences of a Steam Line Break Accident' for Boiling Water. Reactors."

• Dose Equivalent 1-131

• • Total activity, E is average energy of radionuclides mix.

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l Table 2 Control Room Habitability Analysis Assumptions Filtered Flow Rate,1000 cfm I' Recirculatory Flow Rate,1000 cfm L'"?iltered Flow Rate, . 3000 cfm Total Removal Efficiency, 0.95 Atmospheric Dilution, 1*

• Complete mixing.in turbine building volume of 5.3x10 6 3 ft prior to building failure, no atmospheric dilution.

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