ML19354C466
| ML19354C466 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 03/18/1981 |
| From: | Nichols F ARGONNE NATIONAL LABORATORY |
| To: | Igne E Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-CT-1327, NUDOCS 8104090036 | |
| Download: ML19354C466 (2) | |
Text
..emp,%
ARCONNE NATIONAL LABORATORY U- /3 "
9700 Socili CASS h1M, ARCpM, IlrCis 60439 Tdgi<n 312/972-8292 March 18, 1981 Mr. E. Igne, Staff Engineer U.S. Nuclear Regulatory Commission Advisory Co=mittee on Reactor Safeguards Washington, D. C.
20555
Dear Mr. Igne:
Per the request in your letter dated February 6,1981, I have reviewed the documents concerning the reactor pressure. vessel thermal shock event at Indian Point Unit No. 2.
Your letter requested a reply by the end of February, but for reasons unknown to me I received your letter only last week.
For that reason, my review has been far from exhaustive, but perhaps the comments will be of some use.
1.
Document IP2, page 4.
A basis should be given for assuming that a flaw 1" deep is " conservative".
If the " critical" size is 1.7" this assumption is clearly very critical to the analysis.
A basis for the value of Co in the crack growth equation should be given and shown to be appropriate for the actual conditions of interest, e.g. specific environment, R-value, etc.
2.
Document WCAP-9822, page 1-4.
Basis for the 1.7 in. deep critical flaw size should be given.
Also, I consider the statement ".... a flaw of this size is readily detectable during pre-service and in-service examinations and would not be present prior to the event...." unacceptable.
Surely such absolute statements cannot legitimately be made. One can only speak " statistically".
In that vein, as a non-expert in NDE, I find from my discussions with experts that the probability of not detecting a flaw goes pretty close to unity, typically for a flaw size of (20% thickness.
Since the critical flav size being discussed is in that vicinity, I think that quantitative basis is required for assuming this non-detection probability to be low enough to neglect.
TIE LMtR5iTy d O*xp ARcpn L.htR5ht5 A55oasim
/4 ET
- 81040906 N
.P'
2-
[ -
1 i
E. Igna.
~ March 18, 1981 i
+
1 1,
i.
- 3. -Page 2-27A.'
Bases:are required for assuming 5_ events and 60*F water are in some 1
sense " worst case".
j.
4.
Page 2-C-2.
Ditto for h = 2000.
e
~Yours'truly,
, g(.-
(--
t & le - 9 Fred A. Nichols, Consultant
- Metal: Components Subcommitte Advisory Committee.on Reactor Safeguards FAN:ph
'T a
k.
f
).
i E
5 e
r I
9.
E D
4 i.
w-y w,-
-gy,.9 9yyi-..
e
,We w
y ps y-9 g"*.9 ewe-w9 7-=g w-9...p%yis-rw s-
%9gp.#angmig 7 y yy yy9g.
y-
+79 9,. 99 p p 9 9 +.q p.y m
y
.pm La+p - y y p
3-q - g v 9-p e..g enp 9p.y w