ML20148J492

Safety Evaluation Supporting Amend 13 to License DPR-3

ML20148J492
Person / Time
Site:	Yankee Rowe
Issue date:	07/16/1975
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML19291D047	List: ML20148J476 ML20148J486 ML20148J492 ML20148J496
References
NUDOCS 8011240178
Download: ML20148J492 (2)

Text

, UNITE] STATES f ILEAR REGULATORY COMMISSluN

( *

, W AS HINGTG N. D. C. 20 5 5 5 -

=

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION g

SUPPORTING AMENDMENT NO.13 TO FACILIT OPERATING LICENSE DPR-3 L.

Eih===-

(CHANGE NO. Il6 TO THE TECHNICAL SPECIFICATIONS)

• N.i '

YANKEE ATOMIC ELECTRIC COMPANY  ;;;

YANKEE NUCLEAR P0h'ER STATION (YANKEE-R0h'E) v::

DOCKET NO. 50-29 p

[g:;

Introduction

.. By letter dated January 13, 1975, and supplemented by letters dated February 19 and April 17, 1975, Yankee Atomic Electric Company (the licensec) requested a change in the Technical Specifications appended .

to License No. DPR-3 for the Yankee Nuclear Power Station (Yankee- ^ ~

Rowe). The proposed change involves a revision of the reactor protection system set points for the low main coolant flow scram in terms of parameters appropriate for the existing loss-of-flow protection instrumentation. '

Discussion E.!

Originally, the Yankee-Rowc protection system included low main coolant r flow trips that were initiated by signals derived from AP across the ...

steam generators. A low flow reactor scram occurred when coolant flow I' decreased to 80 percent of normal coolant flow in any 2 out of 4 re etor coolant loops during 4 loop operation. To decrease the time associated with this low flow reactor protection instrumentata ,

licensec has installed new instrumentation that provides los- -

iow protection from signals derived from abnormal pump motor curre, conditions, viz. undercurrent and overcurrent signals. An undercurrent conoition which is indicative of pump breaker trips results in loss of flow. An overcurrent condition which is indicative of pump binding a]so results in loss of flow. This existing loss-of-flow reactor protection system is described in the licensec's Proposed Change No. 96 which was submitted on _

August 6, 1971, and was approved by us by our issuance of Change No. 97, h dated April 14, 1972. The licensec has operated the plant with under and '

overcurrent loss-of-flow trip point settings, and now proposes the

. _ , addition of trip set point limits in Tabic 1 in the Technical Specifications which are approprinto for the existing loss-of-flow reactor protection instrumentation.

4

U 2 'I b km

(

.  :.s_

ii::: - .

E Evaluation , -

E li.

The proposed loss-of-flow trip set points, (undercurrent and overcurrent $~ ?

to the coolant pump motors) are appropriate parameters for the existing loss-of-flow instrumentation. The addition of these set point limits K[_.

E=

~

in Table 1 of the Technical Specifications was inadvertently omitted  ;

when Change No. 97, which approved the use of pump motor current for low _

.s flow trip, was issued. We have reviewed the information including pump performance curves submitted by the licensee to clarify the selection of -

the set points ampere values (not less than 240 amperes or more than 960  ; Y amperes to the main coolant pump motors) that are used for the existing R loss-of-flow protection instrumentation. We conclude that these settings p j provide the intended loss-of-flow protection function. Therefore, e .y the licensee's proposed protection system set points are acceptable. -

El This change is implemented by revision of Table 1 and page 6. E l

To provide even greater assurance that the reactor will be scrammed  :

)

automatically in any postulated event that could involve a significant j reduction of reactor coolant flow (80 percent of normal flow), the ~

licensee has agreed to reconnect the original low main coolant flow E<.

protection instrumentation using AP signals across the steam generators, 5 This instrumentation which has previously been reviewed and approved 7;ii l by us will be reconnected and made operable during the next outage [@ ij commencing about October 18, 1975, for refueling the reactor with Core b.! .a XII. We conclude that this action and the implementation schedule to be-o bt,  !

acceptable. Pursuant to discussion with the licensee we have left the h specified requirements for this instrumentation in Table 1 and Section I*

D.2.d(2) and have added a notation that they become effective on the date of reactor startup with Core XII.

Conclusion .

We have co cluded, based on the considerations discussed above, that:

(1) because the change does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the change does  :

not involve a significant hazards consideration, (2) there is reasonable h assurance that the health and safety of the public will not be endangered b by operation in the proposed manner, and (3) 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 defense and security or to the health and safety of the public.

j Date: JUL 161975 t

1 l

l l

i

, -+- r -

. -, ---%, -.g W