ML17037B514
| ML17037B514 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 11/01/1977 |
| From: | Dise D Niagara Mohawk Power Corp |
| To: | Lear G Office of Nuclear Reactor Regulation |
| References | |
| Download: ML17037B514 (6) | |
Text
U.S. NUCLEAR REGULATORY Co ION t
NRC FORM 195 (2-7B)
"NRC DISTRIBUTIONFOR'ART 50 DOCKET MATERIAL DOC ET NUMBER FILE NUMBER Mr. George Lear FROM:
Niagara Mohawk Power Corp+
11/1/77 DATE RECEIVED 11/4/77 LETTER ORIGINAL COPY 0 NO TO R IZE D UNCLASSIFIED PROP INPUT FORM NUMBER OF COPIES RECEIVED DESCRIPTION f~
Qg 7 7 ~ C.e.gi~~
ENCLOSURE Consists of information concerning relief valve actuagion for Nine Mile Point Unit Aoi 1
'ine Mile Point Unit No+
1 RJL 11/7/77 (2-P)
CH CHIEF:
PROJECT MANAGER:
LIC. ASST:
FOR ACTION/INFORMATION ENVIROIQIENTAL ASSIGNED AD:
M ORE LTR BRANCH CHIEF:
B.
HARLESS INTERNALDISTRIBUTION T SYSTEMS SITE SAFETY G
ENVIRON ANALYSIS DENTON 8 MULLER GOSSICK G STAFF ANAGEMi ENT LINS
'ENGINEERING ACTOR SAFETY ROSS NOVAK ROSZTOCZY CHECK L TO BAER TL R CTORS ENVIRON TECH ERNST BALLARD L OD TECH AMMILL 2
ALYSIS VOLLMER LPDR:
HANCHETT) 16 CYS SENT CATEGOR LTZMAN EXTERNALDISTRIBUTION ER CONTROL NUMBER 773llplO7 NRC FORM 198 IO 78I
~ '
~
'I 4
t'
E'JIihto~y ggLIF NIAGARAMOHAWKPOWER CORPORATION
,)IttI~t';
NIAGARA '~
MOHAWK 300 ERIE BOULEVARD. WEST SYRACUSE, N Yg 13202 November 1, 1977 Director, Nuclear Reactor Regulation Attn:
Mr. George Lear, Chief Operating Reacto'rs Branch $ 3 U.
S. Nuclear Regulatory Commission Washington, D.
C.
20555 hr Nay~<r ~Sg
~~/fg~ IIIIIIII Et 04 Re:
Nine Mile Point Unit 1 Docket No. 50-220 DPR-63 Gentlemen:
On October 18, 1977 Niagara Mohawk notified the Office of Inspection and Enforcement, Region I, of a potentially reportable condition relating to relief valve actuation for. Nine Mile Point Unit 1.
Since then a meeting was held on October 27, 1977 with members of the Nuclear Regulatory Commission and the Mark I Owners Group in Bethesda, Maryland.
The purpose of that meeting was to discuss the effects on the Mark I containment.
General Electric has made a survey of operating experience which indicates that many isolation events (greater than 100) have occurred both during normal operation and start up tests.
The survey showed that in only two (2) cases has greater,.than one (1) valve experienced 2nd actuation.
No evidence. of detrimental effects on the suppression chamber have been observed.
General Electric's analysis for Nine Mile Point Unit 1 showed that there is no safety concern even if three (3) valves experience a second actuation.
The Mark I Containment Short Term Program acceptance criteria strength ratio of 0.5 was used as a guideline.
The strength ratio for,the highest stressed portion,of the sup-pression chamber support structure (inner, column) was 0.2.
In
- addition, the shell stress was only 3.73 ksi.
773l1010y
(e i
Hr. Ceorge Lear U.
S. Nuclear Regulatory Commission Page Two November 1,
1977 lit l P~L l,$
H i(~>>
Continued operation oG~Nine',Mile 'Point Unit 1 is justified throughout the duration, of the Long Term Program.
'Such operation will not result in undue risk to the health and safety'f the public.
Very truly yours, NIAGARA,MOHAWK POWER CORPORATION Donald P. Disc Vice President-Engineering MGM/szd
R~C~~~<g gpgUtfEkT PiROCESS1>fG ug~
19ff NAY Q
pg