ML20056F417
| ML20056F417 | |
| Person / Time | |
|---|---|
| Issue date: | 03/12/1993 |
| From: | Remick F NRC COMMISSION (OCM) |
| To: | Chilk S NRC OFFICE OF THE SECRETARY (SECY) |
| Shared Package | |
| ML20056F391 | List: |
| References | |
| REF-10CFR9.7 NUDOCS 9308270192 | |
| Download: ML20056F417 (4) | |
Text
"
y m..
7; UNITED STATES y $.
f( ;5 NUCLEAR REGULATORY COMMISSION i
i O gV, l W ASHIN GTON. D.C. 20555
/
%c, sn :
anict or ise March 12, 1993 C CMMISSIO'40 R MEMORANDUM FOR:
Samuel J.
Chilk Secretary," the Commission l
FROM:
Ectc c mick
[
f
SUBJECT:
Y-93-043, " REGULATORY ANALYSIS GUIDELINES s
OF THE U.S.
NUCLEAR REGULATORY COMMISSION With the exception of Enclosures 3 and 4, I have now read the i
cubjcct document and reluctantly conclude that it is not yet-ready to issue for public comment.
My basis is the lack of editorial clarity of a section of the document; I reserve judgment on the merits of the proposals until after discussions with the staff and after reviewing any further ACRS and public comments.
Large portions of the document are well written and I commend the staff for the conscientious effort to develop the document and to incorporate most of the ACRS comments contained in the Committee's letter of November 12, 1992 to the EDO (I reserve judgment as to whether I agree with all the ACRS comments).
My major reservations are associated with Section 3 of the document, on the subject of Safety Goal Considerations.
Section 3 is a new section in the Regulatory Analysis Guidelines.
The ACRS members indicated that they "believe this to be such an important document that even a draft version to be issued for public comment should reflect high levels of intellectual and technical content, coherence, and clarity of thought and presentation."
The ACRS members indicated that they " expect to review the revised document before it is issued for public comment."
I agree with the ACRS that the importance of this document merits extra attention and care.
Further, I do not see any urgent need for issuing the document if further clarification is needed.
The following are examples of the difficulties I find with Section 3 sf the document, difficulties which I believe could mislead cr confuno readers and thus make meaningful public comment and staff implementation more difficult.
On page 3.1, staff states:
"MRC's safety goal policy addresses a level of acceptable residual individual risk from operation of power reactors 9308270192 930331 PDR 10CFR PT9.7 pgg
~ ~ -..
i 8
L 1'
i I
judged to be lower than that associated with adequate protection, that is the risk. level above which continued operation would not be allowed."
While the phrase, "that is the risk level above which continued operation would not be allowed" refers to adequate protection, an uninformed reader (e.g., new employee or new contractor) could i
interpret it to refer to the safety goal policy statement.
The i
sentence might be better phrased as follows (shading indicates additions):
"NRC's safety goal policy addresses a level of acceptable residual individual risk from operation of power reactors judged to be lower than=that associated with adequate protection.
Adequate /protecEich is the. risk level above which continued' operation woul~d"'not be allowed."
i On the same page, staff further states:
"If the proposed safety goal criteria are satisfied, it is to be presumed that the substantial additional protection standard of 10 CFR 50.109 (a) (3) is met for the proposed action."
(My emphasis.)
I searched the document for something identified as " safety goal criteria."
I found reference to:
" safety goal objectives" (are these the two quantitative.[ health] objectives in the safety goal policy statement or are they the subsidiary. objectives which are not in the policy statement?); " screening criterion" (for ACDF of 105); " guidance" (for the unnumbered figure on page 3.8 on
" Estimated Reduction In CDF"); " criteria".which should be used regarding subsequent staff action on page~3.11;." staff action criteria" on page 3.12; and, " Safety Goal; Implementation Guidance" as the title _of Figure 3.2.
Although I suspect that l
Figure 3.2 is what the staff refers to as " safety. goal criteria,"
I am far from certain and fear that others may be as uncertain.
Assuming that Figure 3.2 contains the " safety goal criteria," Lit is not clear what is meant by " satisfying the safety goal criteria."
Further, Section 3.3.2 appears to.be a discussion of how to use.
Conditional Containment Failure Probability (CCFP).
.For example, on the top of page 3.10'it is stated.that "The potential for failure or bypass of containment should be determined, if practical, by estimating the conditional containment failure probability (CCFP)."
I agree, however, I do not understand the
~
intervening discussion beginning with.the second paragraph on page 3.10 to the bottom of page 3.11 and.what it has to do with-4 CCFP.
For_ example, what is.the " Estimated Reduction in
^!
Likelihood of Containment Bypass With Core Damage Accidents?"
Does "with core. damage accidents" mean "given a core damage 2
a.
....a..
.._a_,_,,_._.-_a,,..-a...,n..
accident?"
If so, is a breach of the primary system also assumed 4
as a given?
Is core damage equivalent to core melt?
Is the 10 number the same as the large release frequency numcer?
Is it aCCFP?
If the 10* number is the large release frequency number, what is the logic of interjecting that discussion into the discussion which leads to the unnumbered summary table on page 3.12, which is related to oCDF and CCFP?
If the 10' number is not the large release frequency, but is truly the likelihood of containment bypass given core damage, what is the origin of the 10* number?
Further, nowhere in Section 3.3.2, other than in the unnumbered table, do I find mention of the subsidiary CCFP objective of 10".
It appears like magic.
By contrast the subsidiary CFP objective of 10 per reactor year is discussed on 4
page 3.7.
In fact, there is a confusing lack of parallelism in the titles and development of Sections 3. 3.1 and
- 3. 3.2.
I understand the backfit rule context in which the staff states on page 3.5 that " safety goal objectives are to be applied only to safety
- enhancements and evaluated for the affected class of plants."
However, as a separate matter, I would be interested in knowing if, outside of the context of backfit, the safety goal analysis process could be used as a screening tool for considering the relaxation or reduction of certain current regulatory requirements.
The safety goals and objectives, the subsidiary goals and the backfit rule are referred to frequently in the document.
I think it would be helpful to include in this document, perhaps as an appendix, the pertinent parts of the qualitative goals and quantitative objectives from the safety goal policy statement, the pertinent parts of the backfit rule, as well as the subsidiary CDF and CCFP objectives approved for use for LWRs.
Such an appendix, together with consistent use of such terms as
" goals", " objectives", " subsidiary objectives", " criterion",
" criteria", " guidance" and " guidelines", would be extremely helpful to the reader.
Incidentally, the Commission's safety Goal Policy Statement is not included in the Bibliography.
It may also be helpful release the Reaulatory Analysis Guidelines, the Reculatory Analysis Technical Evaluation Handbook, and the A Handbook for value-Impact Assessme'nt at the
- Incidentally, in the unnumbered table on page 3.12, it might be better to indicate ACDF is <10" instead of ACDF is j
10~-104, and CCFP is <10" instead of CCFP is 10 2, etc.
d
,** Also, on page 4.21 it is stated that "For proposed regulatory actions that would relax or reduce current requirements, the backfit rule and the safety goal analysis process and criteria contained in Section 3 are not applicable."
j l
3
)
4j
,~
i
]
j same time.
Staff indicates that the latter two documents will be j
available after April 30, 1993.
l It is for the above reasons that I conclude that the document is j
not jet ready for issuance for public comment.
I prefer that before voting on its issuance, the document be edited and revised as necessary for clarification and,_as the ACRS has strongly i
j requested, be reviewed again by the ACRS.
j cc:
The chairman Commissioner Rogers Commissioner Curtiss Commissioner de Planque EDO OGC ACRS l
i i
4 i
..