ML19224A864
| ML19224A864 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/17/1979 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Scherer A ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
| References | |
| NUDOCS 7906070055 | |
| Download: ML19224A864 (3) | |
Text
..,
ML & FDJ2 I
E f
e AR RfCg k'i UNITED STATES E*3, NUCLEAR REGULATORY COMMISSION
- C W ASHINGTON. D. C. 20555 o
5
,o MAY 171979 Mr. A. E. Scherer, Licensing Panager Combustion Engineering, Incorporatad 1000 Prospect Hill Road Windsor, Connecticut 06095
Dear Mr. Scherer:
SUBJECT:
ACRS RECOMMENDATIONS RELATING TO TMI-2 ACCIDENT As you know, the Advisory Comittee on Reactor Safeguards (ACRS) has written three separate letters to the Cormiission relating to the TMI-2 accident.
These letters were issued on April 7, April 18, and April 20, 1979. Each of these letters contains specific recomendations which must be addressed.
The ACRS has discussed these recommendations with the staff and industry at recent ACRS subccmittee and full comittee meetings. We anticipate that this dialogue will continue in the forth-coming ACRS subcomittee meeting on TMI-2 (May 31-June 1).
For this reason, we are requesting that all light water reactor vendors provide the staff with a concise discussion and position on each of the ACRS recomendations relating to TMI-2.
For your convenience, we have provided in the enclosure a list which contains each ACRS recormiendation of which we are aware.
We request that you provide your response to each of these ACRS recomendations to be received by the staff no later than Pc 23, 197 9.
If you require any clarification of the matters discussed herein, please contact C. J. Heltemes, Jr.
Mr. Heltenes' phone number is (301) 492-7745.
Sincerely, N
'\\
\\
VD f D. F. Ross, Deputy Cirector Division of Project Management Of fice of f.'uclear Reactor Regul ation Enclosure :
As stated 169 049 790eo 7g,s y
+
[
ENCLOSURE s
i
~
ACRS RECOMMENDATIONS I
A.
Letter, M. Carbon to Chai man Hendrie, dated April 7,1979 f
Recommendation 1 - Perform further analyses of small break transients and accidents.
l Recommendation 2 - Provide operator additional infonnation and means to follow the enurse of an accident; as a minimum, consider expeditiously:
(a) unambiguous RV level indication I
(b) remotely controlled vent for RCS high points 6
l Recomendation 3 - Item 4b of Bulletin 79-05A considered unduly pre-scriptive in view of uncertainties in predicting
~.
course of anomalous small break transients / accidents.
B.
Letter, R. Fraley to Comissioners, Gated April 18, 1979 Y.
Recommendation 1 - Natural Circulation-related Items a.
Detailed analyses of natural circulation mode, i.
supported as required by experiment, by licensees and NSSS vendors, u__
b.
Develop procedures for initiating natural circulation.
I t
c.
Provide operator means for assurance that natural circulation has been established, e.g., by install-L ation of instructicas to indicate flow at low E
velocities.
t I
d.
Expeditiously survey operating PWR's to determine I
whether suitable arrangements of PZR heaters and L
reliable on-site power distribution can be provided I
to assure this vital aspect of natural circulation g
capability.
E'
[
e.
Operator should be adequately informed concerning RCS t
conditions which affect natural circulation capa-i bility, e.g.,
t (1) indication that RCS is approaching saturation condition by suitable display to operator of 1
T and PZR pressure in conjunction with j
sEe&Tamkables i
L (2) use of flow exit temperature indicator by fuel
{
assembly thermocouples, where available, f.,
169 050
^
e Erclosure - page 2 h
ACRS Recomendations lI Recomendation 2 - Thennocouples used to measure fuel assembly exit temperatures to determine core parformance should be used, where currently available, to guide operator f
concerning core status (full range capability).
Recomendation 3 - Operating reactors should be given priority regarding definition and implementation of instrumentation to 5
diagnose and follow the course of a serious accident, g
including I
(a) improved sampling procedures under accident conditions r.
l (b) improved techniques to provide guidance to
[
offsite authorities.
I Reconnendation 4 - Reiterates previous recommendations that high priority
[
be given to "research to improve reactor safety" t
(a) research on behavior of LWR's during anomalous transients b
(b) NRC to develop capability to simulate wide range of postulated transients and accident conditions.
I Recommendation 5 - Consideration should be given to additional monitoring of ESF equipment status, and to supporting services, to helo h-assure availability at all times.
[
C.
Letter, M. Carbon to Acting Chairman Gilinsky dated April 20, 1979 t
Recommendation 1 - Initiate immediately a survey of operating procedures for achieving natural circulation, including:
(a) event involving loss of offsite power (b) consideration of role of PZR heaters.
s t
k-a a
1 r
n
!p!-
si
'l 169 051 a
?