ML19224A863
| ML19224A863 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/17/1979 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Taylor J BABCOCK & WILCOX CO. |
| References | |
| NUDOCS 7906070053 | |
| Download: ML19224A863 (3) | |
Text
- * - - -.
e E(g, %g.,%
UNITED STATES h
NUCLEAR REGULATORY COMMISSION 3.,,
E WASHINGTON, D. C. 20555 s
J
/
MAY 171979 Mr. James H. Taylor Panager, Licensing Babcock & Wilcox Company P. O. Box 1260 Lynchburg, Virginia 24505
Dear Pa. Taylor:
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 Comission relating to the THI-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 subcomittee 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 concite 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 recomendation 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 May 23, 197 9.
If you require any clarification of the matters discussed herein, please contact C. J. Heltemes, Jr.
Mr. Heltemes' phone number is (301) 492-7745.
Si ncerely, b
(4 A^f /
ss, Deputy Di[ector D. F.
~
Division of Project Management Of fice of Nuclear Reactor Regulation
Enclosure:
As stated 169 046 v30co7ms 3
w ENCLOSURE ACRS RECOMMENDATI9NS
- r A.
Letter, M. Carbon to Chairman Hendrie, dated April 7,1979 Recommendation 1 - Perform furi.her analyses of small break transients and accidents.
Recommendation 2 - Provide operator additional infomation and means to follow the course of an accident; as a minimum, j
consider expeditiously:
(a) unambiguous RV level indic.stion (b) remotely controlled vent for RCS high points 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.
E B.
Letter, R. Fraley to Commissioners, dated April 18, 1979 Recommendation 1 - Natural Circulation-related Items p
P a.
Detailed analyses of natural circulation mode,
~
supported as required by experiment, by licensees and NSSS vendors.
b.
Develop procedures for initiating natural circulation.
E c.
Provide operator means for assurance that natural circulation has been established, e.g., by install-ation of instructions to indicate flow at low f
velocities.
j d.
Expeditious'y survey operating PWR's to determine whether suitable arrangements of PZR heaters and reliable on-site power distribution can be provided c
i to assure this vital aspect of natural circulation capability.
p
[
e.
Operator should be adequately infomed concerning RCS r
conditions which affect natural circulation capa-bility, e.g.,
(1) indication that RCS is approaching saturation condition by suitable display to operator of TsEe&T and PZR pressure in conjunction with t
b am tabies
'l (2) use of flow exit temperature indicator by fuel assembly thermocouples, where available, 169 047 t
i t
r
. ~ -..
Enclosure - page 2 ACRS Recommendations Recomendation 2 - Thermocouples used to measure fuel assembly exit temperatures to determine core performance should be used, where currently available, to guide operator concerning core status (full range capability)e Recommendation 3 - Operating reactors should be given priority regarding definition and implementation of. instrumentation to diagnose and follow the course of a serious accident, I
including i
s (a) improved sampling procedures under accident conditions
?
(b) improved techniques to provide guidance to
[
offsite authorities.
Ei Recomendation 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) NRC to develop capability to simulate wide range of postulated transients and accident conditions.
Recomendation 5 - Consideration should be given to additional monitoring of ESF equipment status, and to supporting services, to help assure availability at all times.
C.
Letter, M. Carbon to Acting Chairman Gilinsky dated April 20, 1979 Recommendation 1 - Initiate immediately a survey of operating procedures
{
for achieving natural circulation, including:
f (a) event involving loss of offsite power (b) consideration of role of PZR heaters.
t I
F.
7 r
L t
t i
I 169 048 l
I s