ML20151K857

Safety Evaluation Supporting Amend 112 to License DPR-3

ML20151K857
Person / Time
Site:	Yankee Rowe
Issue date:	07/19/1988
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20151K837	List: ML20151K831 ML20151K853 ML20151K857
References
NUDOCS 8808030300
Download: ML20151K857 (2)

Text

l

~

A KfCg y

['k )

k g UNITED STATES NUCLE AR REGULATORY COMMISSION SAFETY EVALUATION BY THE OFF C F CL AR REACTOR REGULATION SUPPORTING AMENDMENT N0. 112 TO FACILITY OPERATING LICENSE N0. DPR-3 YANKEE ATOMIC ELECTRIC COMPANY YANKEE NUCLEAR POWER STATION l DOCKET NO.50-029 INTRODUCTION By letter dated March 23, 1988, Yankee Atomic Electric Company (YAEC or the licensee) submitted a request for a change to the Technical Specifications (TS) of the Yankee Rowe Nuclear Power Station. The change would modify Technical Specification 3.1.1.1.2 to change the shutdown margin transition temperature from 490*F to 470'F. The licensee has requested this change in order to increase operational flexibility and possibl: avoid large borations during Mode 3 operation. In addition, correction of a typographical error and the i inadvertent onnission of a previously approved surveillance requirement was  ;

requested. -

EVALUATION Yankee Rowe Technical Specification 3.1.1.1.2 specifies two different shutdown margin requirements in Mode 3 depending on the average main coolant temperature. Currently, these requirements change at a transition temperature of 490*F. For temperatures greater than or equal to 490*F, the required shutdown margin is 6% delta k/k or greater as based on the conditions existing at 516*F. For temperatures between 330*F and 490*F, the required shutdown margin is 5% delta k/k or greater as based on the conditions existing at l 330 F. In addition, Technical Specification Table 3.3-2 allows bypass of the l

safety injection (SI) trip function and nonreturn valve (NRV) closure in Mode l 3 when the main coolant temperature is below the transition temperature of l 490'F. The availability or nonavailability of these functions affect the I shutdown margin requirements during a postulated main steam line break (MSLB) accident with a larger shutdown margin required when there is no automatic operation of SI actuation and NRV closure.

The licensee has reevaluated the MSLB based on a lower transition temperature of 470*F and has determined that there is a sufficient amount of shutdown margin to preclude recriticality during either the postulated MSLB accident with the automatic trip functions or without. The staff has reviewed this analysis and found it acceptable. Therefore, the proposed change in transition temperature from 490*F to 470*F is acceptable.

In addition to the transition temperature change, administrative corrections -

were made to Surveillance Requirement 4.1.1.1.2.1 to correc+ a typographical error and to include a requirement to detennine the shutdown margin within one hour and at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter following the discovery of an inoperable control rod. Since these changes merely correct a minor error that was inadvertently omitted from an earlier TS amendment, these administrative changes are acceptable, 8s08030300 880719 PDR AbOCK 03000029 p PDC

~

i 2

The staff has reviewed the recuest by Yankee Atomic Electric Company to change the Mode 3 shutdown margin tronsition temperature in the Yankee Rowe Technical Specifications and we conclude it is acceptable. We further conclude that the proposed inclusion of a surveillance requirement which had been inadvertently omitted is acceptable.

ENVIRONMENTALCONSIDERATIQN ]

An Environmental Assessment for this proposed action was published in the 26 , 1988 (53FR28 83 ). Therein, it was determined I Federal Reoisterchang that the proposed on Jul[s will not have a s gnificant environmental impact i because they will not increase the probability or consequences of accidents, i alter the effluents which moy be released offsite or significantly increase '

occupatiunal raciation exposure.

$9E9LESI90 The staff has concluded, based on the considerations discussed above, that:

(1) there is reasonable assurance that the health and safety of the public will 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 this amendment will not be inimical to the common defensa and security or to the health and safety of the public.

ACKNOWLEDGEMENT Principal Contributors: L. Kopp M. Fairt11e Dated: July 19, 1988 l

l I