ML20059D474

Safety Evaluation Supporting Amends 78 & 72 to Licenses NPF-35 & NPF-52,respectively

ML20059D474
Person / Time
Site:	Catawba
Issue date:	08/30/1990
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20059D466	List: ML20059D464 ML20059D474
References
NUDOCS 9009070055
Download: ML20059D474 (4)

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,t NUCLE AR REGULATORY, COMMISSION j!

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.= 78 TO FACILITY OPERATING LICENSE NPF-35 AND AMENDMENT-NO.72 TO FACILITY OPERATING LICENSE NPF-52 DUKE POWER COMPANY. ET AL.

CATAWP.A NUCLEAR STATION. UNITS 1 AND 2 DOCKET N05. 50-413 AND 50-414

1.0 INTRODUCTION

By letter dated December 21, 1987 Duke Power Company, et al. (the licensee) proposedamendmentstoTechnicalSpecification(TS)4.7.6d.regardingControl-Room Aren Ventilation System Surveillance Requirements for Catawba Nuclear-St6tien, Units.1-and 2, that would extend the carbon adsorber sampling frequency

'from 720-hours to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br />. By letters dated July 14, 1989, April 19 and

. June 12, 1990, the licensee proposed aoditional changes to TS-3.7.6a., 4.7.6c.,

4.7.6f., and 4.7.6., and TS Bases 3/4.7.6. These changes would provide 9

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adniinistrative clarification and more conservative bypass leakage and methyl todide' penetration acceptance criteria, 2.0+ EVALUATION Theilicensee's proposed deletion of the phrase "...with flow through the HEPA filters"and' activated carbon-adsorbers" from TS 3.7.6a. is justified because-

'there is no bypass line in the as-built station, and control room air is continuously passed through HEPA filters and carbon adsorbers. Therefore, the phrase is unnecessary..

bypass leakage past the filtering systems for Unit 1 (1%)parate criteria for -

Current TS 4.7.6c., TS 4.7.6f., and TS 4.7.69. contain se andUnit2(0.05%).

'The proposed change would limit bypass leakage to less than 0.05% for both units.1 This change is in the direction of increased conservatism and, therefore, it is' acceptable.

The licensee proposed to change the criterion for methyl iodide penetration of

. the carbon adsorbers in TS 4.7.6c.2 and TS 4.7.6d. f rom l% to 0.175%, and to -

add to_4.7.6d. the statement: " Activated carbon adsorber samples are t6sted at

-30 degree C."

These changes are in the conservative direction and, therefore, they are acceptable.

.1he Lt ember 21', 1987, amendment request proposed to extend the carbon adsorber bed sampling frequency from 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br />. The submittal indicated that removable sample canisters were used to obtain carbon adsorber samples.

This practice has been discontinued and currently samples are 9009070055 e00830 PDR ADOCK 05000413 P

PDC

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i obtained by the grain thief method in which the thief is inserted directly into the carbon bed. This methoc provides more representative sampling of the carbon bed.

The Catawbt huclear Station Control Room Area Ventilation System is equipped with state-of-the-art 4-inch thick carbon adsorber beds pretreated with Triethylenediamine (TEDA). The Control Room Area Ventilation System filter units have no bypass line. Train A or Train B must operate in the filtered mooe continuously. When a train is in operation, its_ associated heater also runs. continuously.

The TEDA carbon beds have not been replaceo since initial operation.

The licensee's justification of the extended sampling interval is based on the

. history of laboratory methyl iodide penetration tests on carbon bed samples.

As of the July 14, 1989 submittal, a total of 67 tests have been performed over a period of 6 years covering typical atmospheric and seasonal conditions.

Carbon bed sampics taken by the grain thief method were tested for methyl iodide penetration at 30" Centigrade,101 kpa pressure and 70% relative I

humidity._ Tests assuming a 2-inch thick carbon bed gave methyl iocide removal efficiency results ranging from 99.98% to 99.94% for one filter unit and from 99.99% to 99.76%-for the stcond unit. When these results, assuming a 2-inch thick carbon bed, were corrected for the fact that the actual carbon beds are l

4 inches thick,- the methyl iodide penetration would have been less than 0.01%

l-for all 67 tests. This more than meets the acceptability criterion of 0.175%

L in the amended TS 4.7.6c.

l These tests demonstrate that the methyl iodide adsorption efficiency of the carbon beds has not been significantly degraded after 6 years of circulating outside air. With so little change in adsorption efficiency in 6 years, it is i

unlikely that extending the surveillance interval from 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> t'o 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> would significantly. increase the risk of failing to observe an increaso in L

penetration above 0.175%. The TS 4.7.6d. change has no adverse impact on safety and would not pose an undue risk to the public health and safety.

Therefore, the NRC staff finds the change in surveillance interval acceptable.

I-l The licensee proposed clarifying changes to TS Bases 3/4.7.6, " Control Roerr i.

Area Ventilation System." One of the changes states that: "The Control Room Area Ventilation System filter units have no bypass line.

Either Control Roorr.

i Area Ventilation System train must operate in the filtered mode continuously.

When a train is in operation, its associated heater also runs continucusly."

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This chanpe_is acceptable because it corresponds to the as-built design of the-station and provides continuously filtered air to the control room areu.- The

- other change adds a clarifying stateraent regarding the conouct of the 18-month surveillance to verify that a positive pressure exists in the control room l

area. This clarification is acceptable.

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3.0 ENVIRONMENTAL CONSIDERATION

These amendments involve a change in requirements with respect to the installation l

or use of a facility component. located within the restricted area as defined in-10 CFR Part 20 and changes in surveillance requirements. The staff has determined that the amendnents involve no significant increase in the amounts, and no

.significant change in the types, of any effluents that may be released offsite 1

and that there is no significant increase in individual.or cumulative occupational j

radiation exposure. The Commission has previously issued a proposed finding i

that the aniendments involve no significant hazards consideration, and there has been no public conenent on such finding. Accordingly, the amendnents meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).

Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental l

essess:nent need be prepared in connection with the issuance of these amendments.

4.0 _ CONCLUSION The Commission's proposed determination that the amendments involve no significant i

hazards cnnsideration was published in the Federal Register (54 FR 6190) on j

February 8,1989, and (55 FR 4263) on February 7,1990. The Consnission consulted I

with'the State of South Carolim._ No public comments were received, and the St6te of South Carolina did not have any comments. The licensee's letters of i

April 19, and June 12, 1990, clarified certain aspects of the request, but the substance of the changes noticed in the Federal Register and the proposed no l

significant hazards. consideration detern.ination were not affected.

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We have concluded, based on the considerations discussed above, that:- (1)~

there is reasonable assurance that the health and safety of the public will i

not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the~ public.

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Principal Contributor:

K. Jabbour, PDII-3/DRP-I/II S. Kirslis, PDII-3/DRP-1/Il Dated:

August 30, 199J l,