ML20084B687
| ML20084B687 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 02/23/1977 |
| From: | White L ROCHESTER GAS & ELECTRIC CORP. |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20084B683 | List: |
| References | |
| NUDOCS 8304070026 | |
| Download: ML20084B687 (1) | |
Text
D.
O O
. ~.......
RdmjdMy cxy p;m p.J.1 y
==
g h
ROCHESTER GAS AND ELECTRIC CORPORATION e 89 EAST AVENUE, ROCHESTER, N.Y.14649 LEON D WHITE. JR T E L E *e=0% t vics nazioenet a...cocav.. 546 2700 February 23, 1977 Director of Nuclear Reactor Regulation ATTN: Mr. A. Schwencer, Chief Operating Reactors Branch #1 U. S. Nuclear Regulatory Commission Washington, L C.
20555
Subject:
Reacti rity Insertion Curve used for safety analyses R. E. G.inna Nuclear Power Plant, Unit No.1 Docket No. 50-244
Dear Mr. Schwencer:
RG6E was notified by Westinghouse Electric Corporation that the negative reactivity insertion curve as a function of time after reactor trip used in the FSAR (FSAR Figure 14-1) and in reload evaluations was not sufficiently conservative. Westinghouse has revised the curve and has evaluated the impact of the revision on previous transient analyses. It was determined that there was a negligible impact on all transients except the loss of flow transient. The impact on the most recently performed loss of flow transient, which was submitted with an application for Technical Specification change dated November 1,1976, is small and the FSAR stated 1.30 minimum DNBR criterion is satisfied. The minimum DNBR for the November 1,1976 analyses at a 55 Hz trip setpoint and a 5 Hz/sec fre-quency decay rate is reduced from 1.615 to 1.594. Thus, application for Technical Specification change is still valid.
In our letter of February 11,1977 regarding margins available to accommodate fuel rod bowing, we referenced the above November 1,1976 loss of flow analyses and stated that a 30.5% margin was available to the 1.30 DNBR criterion. The change in trip reactivity curve reduces this margin to 28.9%. The margin of 22.2% reported for transients terminated by the overtemperature 6T setpoint is unchanged. Thus, the conclusion of our February 11 letter, that,22.2% margin is available, is unchanged.
Very truly yours, Kon%n.
L. D. White, r.
0304070026 770223 PDR ADOCK 05000244 s
7
^
/'
v Ra o
R..,m,n
\\.y$
l'
'"=
- c.; e ROCHESTER GAS AND ELECTRIC CORPORATION e 89 EAST AVENUE, ROCHESTER, N.Y.14649 LEON D WHlf E. JR ratse ome vice passiosur asia coor vis 5 4G.2 700 February 23, 1977 4b E,,N Y
Q:q%qh
//
tY'f1LY' G
b '.' V
~
-3 Mr. James P. O'Reilly, Director U. S. Nuclear Regulatory Commission MAR 1 1977* 1 Office of Inspection and Enforcement 6' u.s. g g ma Reglon I emaos 631 Park Avenue g
King of Prussia, Pennsylvania 19406 N
Subject:
Reportable Occurrence 77-02 (14-day report), Reactivity Insertion Curve used for safety analyses R. E. Ginna Nuclear Power Plant, Unit No.1 Docket No. 50-244
Dear Mr. O'Reilly:
In accordance with Technical Specifications, Article 6.9.2a, the attached report of Reportable Occurrence 77-02,14-day, is hereby submitted. Also,
a copy of our letter to Mr. A. Schwencer concerning this matter is attached for your information. Two additional copies of this letter and the attach-ments are enclosed.
Very truly yours,
L. D. White, Jr.
Attachments cc: Dr. Ernst Volgenau (40)
Mr. William G. Mcdonald (3) q 2037
,