ML20009A197
| ML20009A197 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/29/1981 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Novak T Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-1.C.1, TASK-TM TAC-44335, NUDOCS 8107090187 | |
| Download: ML20009A197 (2) | |
Text
.
9 suuo SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 S Street. Box 15830, Sacramento, California 95813; (916) 452-3211 5
S M
June 29, 1981
~
y
' S-S T M NOVAK g\\,.
g#
p',
~
DIVISION OF LICENSING
,#p5
/,',
U S NUCLEAR REGULATORY COMMISSION 9\\ ** '
[P
/
[Y N-WASHINGTON D C 20555 RANCHO SECO UNIT 1 DPR-54 DOCKET NO. 50-312 NUREG-0737, ITEM l.C.1 ABNORMAL TRANSIENT OPERATOR GUIDELINES (ATOG)
In resporise to NUREG-0737, item 1.C.1, the District committed to implement Abnormal Transient Operator Guidelines (ATOG) for Rancho Seco Unit 1, which would be similar to the draft guidelines prepared for and transmitted by Arkansas Nuclear One, Unit 1.
The plant spect fic guidelines (applicable to Rancho Seco) are in preparation and will be implemented per the schedule detailed in our letter of January 16, 1981.
In the following paragraphs you will find our response to the speci fic items identified in your letter of June 1,1981.
These responses reference the submitted draft guidelines made by Arkansas:
1.
The Event Trees provided consider the failure of all relevant challenged systems including failures involving multiple systems.
I 2.
Multiple failures were qualitatively analyzed on a l
functional level. The basic transient code used for l
the computer simulation protion of the ATOG program was TRAP 11.
The version used for the ANO-1 guidelines l
had an equilibrium pressurizer, these insurge rates were used as inputs into the DYSID code (a nonegallibrium pressurizer model) and the Reactor Coolant System pressure response was obtained. The combination of these two codes was used as input in developing Part ll of the guidelines, in the case of a steam line break inside the reactor building, the CONTEMPT code was used to predict building pressure response.
I 3
Operator errors of omission and commission are addressed in the Event Trees extensively. The basis for your question gives us concern that you may not have adequately reviewed the submitted material.
\\
l 8107090187 810629 PDR ADOCK 05000312 P
PDR i,i.,
s r
.9 4 ' e y tii tc
.. 1t v
_r v: sr t
T H NOVAK June 29, 1981 4.
a.
SG tube ruptures occurring simultaneously in more than one steam generator will not be addressed in this program.
It may be addressed later in a separate study whose status is currently uncertain. The current program has been underway for approxirately two years and should be complete within about six months. Belated modi-fications to the program of this significant nature would det rimentally perturb the continuing progress of the program, b.
This is addressed in the Event Trees by the use of the branches with inadequate High Pressure injection (HPI) flow.
Inadequate flow includes zero flow.
c.
See 1. on preceding page.
d.
This is explicitly addressed in the Event Tree on Loss of Main Feedwate r, Dwg. No. 1100937, 5
Instructions to go to inadequate core cooling guidelines are included in the draft guidelines.
Inadequate core cooling guidelines have been previously submitted and are being incorporated into the Rancho Seco speci fic ATOG.
We feel that the present AT0G program fully complies with the NRC requi rements, as they have evolved and are presently defined in NUREG-0737, i tem. l.C.I.
Should you requi re further information or elaboration, we would suggest meeting with you to discuss the details of those requi re-ments so that we may proceed to a point where our implementation commitments will be met.
[
]
w +'~
lohn J. Mattimoe Assis tan t Gene ral Manage r and Chief Engineer
.