ML20056F399
| ML20056F399 | |
| Person / Time | |
|---|---|
| Issue date: | 07/21/1993 |
| From: | Chilk S NRC OFFICE OF THE SECRETARY (SECY) |
| To: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| References | |
| REF-10CFR9.7 NUDOCS 9308270131 | |
| Download: ML20056F399 (6) | |
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NUCLEAR REGULATORY COMMISSION;
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OFFICE OF THE July 21, 1993 SECRETARY t
MEMORANDUM FOR:
James M. Taylor Executive Director for Merations l'
FROM:
Samuel J.
Chilk, Secre
SUBJECT:
SECY-93-167 - REGULAT0gY ANALYSIS GUIDELINES OF THE U.S. NUCLEAR REGdLATORY COMMISSION The Commission (with all Commissioners agreeing) approved publication of a notice in the Federal Reaister announcing the availability for public comment of the proposed'" Regulatory Analysis Guidelines of the U.S. Nuclear Regulatory Commission".
The Commission requested the following actions be taken with respect to the Guidelines document prior to making it available for public comment.
i 1.
The attached edits are'to be made; 2.
The reference to a "large release definition" as an l
open item should be deleted; l
3.
Additional clarification of the staff's use of net i
values as opposed to impact /value ratios should be included.
The staff should include ~this as one of the FRN issues identified.for' comment during the public comment period and reference the ACRS' comment in the 11/2/92 letter.
4.
The. reference on p. 4.9 to acceptable methods for estimating values and impacts should be clarified to i
remove an implication that a " median" estimate is not a
" point" estimate.
A similar clarification should be i
made on p. 5.13 of the Regulatory Analysis Technical Evaluation Handbook (Enclosure 7 of SECY 93-167).
i The Commission also requested that Chapter 3 of the Handbook be 1
l revised to reinforce its linkage to sections of Chapter 5 where l
detailed guidance is provided.concerning the-safety goal SECY NOTE:
THIS SRM, SECY-92-391, AND'THE VOTE SHEETS OF ALL COMMISSIONERS WILL BE MADE PUBLICLY AVAILABLE 10 WORKING DAYS FROM THE DATE OF THIS SRM 9308270131 930721 PDR. 10CFR f
PT9.7
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i evaluation.
Additionally, the Handbook should be revised to include, as an appendix, the pertinent parts of the safety goal policy statement (i.e.,
qualitative goals, quantitative objectives) and the backfit rule.
The proposed public announcement (Enclosure 6 of SECY 93-167), when issued, should include an appropriate' reference to the Federal Recister notice-and the closing date for the comment period.
(EDO)
(SECY Suspense:
8/23/93).
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Attachment:
i As stated cc:
The Chairman Commissioner Rogers Commissioner Remick Commissioner de Planque OGC
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Office Directors, Regions, ACRS, ACNW (via E-Mail).
1 SDBU/CR, ASLBP (via FAX) l 1
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1 3.1 Safety Goal Decision Criteria 1
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NRC's safety goal policy addresses a level of acceptable residual individual risk from operatio f power reactors judged to be lower tha that associated LW l jovel us a cin$ed wrI4lP adequate protection is e%d s w Me h V
oe-with adequa e pro tion. f g ct. pr;v u continued j
g operation would not be allowed. -A; : result,The safety soal evaluation, as
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discussed in this section, is applicable only to regulatory initiatives considered to be generic safety enhancement backfits as defined in the backfit rule (10 CFR 50.109).
If the proposed safety goal decision 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.
As discussed in Section 2.3 of these Guidelines, relaxations of requirements are not backfits and thus do not fall within the scope of the backfit rule.
As a result, relaxations or the elimination of requirements are not subject to the safety goal evaluation of this section.
In justifying a proposed backfit under the backfit rule, the burden is on the staff to make a cositive showing that a generic safety problem actually. exists and that the proposed backfit will both address the problem effectively and provide a substantial safety improvement in a cost-beneficial manner.
i 3.2 Procedure The staff must first determine whether the subject regulatory action needs to consider safety goals. The discussion above in Section 3.1 provides guidance for making this determination.
If a safety goal evaluation is required, the results of the evaluation will establish whether a regulatory analysis should be done (Figure 3.1).
If the proposed regulatory action meets the safety goal decision criteria, the regulatory analysis should include the results of the safety goal evaluation as well as the follow-on value/ impact analysis.
Figure 3.1 depicts all steps performed in a regulatory analysis that is subject to a safety goal evaluation.
Depending on the results of steps C and D, the regulatory analysis can be terminated.
In performing steps C and D, a PRA should be relied upon to quantify the risk reduction and corresponding 3.2
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l l-I Those involving core damage and release into an intact containment with early containment failure occurring Those involving core damage and for which the containment system is breached as a result of accident phenomena either prior to or early in the core damage or melt progression Those involving pre-existing conditions that cause loss of containment integrity prior to core damage (e.g., large openings)
Those for which containment is bypassed entirely and have high probability of causing core damage to occur (intersystem 1.0CA).
It should be noted that the safety goal decision criteria described here do That6,Oegeed/
not address issues that deal only with containment performance.
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issues which have no impact on core damage frequency (delta CDF of zero) g cannot be addressed with the safety goal decision criteria.
However, because mitigative initiatives have been relatively few and infrequent compared with accident preventive initiatives, mitigative initiatives will be assessed on a case-by-case basis with regard to the safety goals.
Given the very few pro).: ad regulatory initiatives that involve mitigation, from a practical perspective, this should have little overall impact on the usefulness of the safety goal decision criteria.
3.11
l FIGURE 3.2 SAFETY GOAL DECISION CRITERIA 1E-03 PROCEED TO V/I PORTION PROCEED TO V/I PORTION OF OF REGULATORY ANALYSIS REGULATOT.Y ANALYSIS
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( PR.tORITY )
Q 1E-o4 m
MANAGEMENT DECISION PROCEED TO V/I PORTION gU WHETHER TO PROCEED OF REGULATORY ANALYSIS Hg WITH V/I PORTION OF wo REGULATORY ANALYSIS ES 1E-oS 5E U
MANAGEMENT DECISION NO ACTION WHETHER TO PROCEED WITH g
V/I PORTION OF REGULATORY sc:
ANALYSIS Q
i ESTIMATED CONDITIONAL CONTAINMENT FAILURE PROBABILITY **
- A determination is needed regarding adequate protection or compliance; as a result, a value/ impact analysis may not be appropri ate.
- Conditional upon core damage accident that releases radionuclides into the containment (see Section 3.3.2).
3.3.3 Summarv of Safety Goal Decision Criteria Guidance have j
The safety goal decision criteria discussed in these sections 4u been j
o summariIed in Figure 3.2, which graphically illustrates these criteria and provides guidance as to when staff should proceed to the value/ impact portion of the regulatory analysis and when a management decision is needed.
Responsible management should review the results and the overall uncertainty and sensitivity of these estimates. A judgment should be made whether substantial additional protection would be achievable and whether continuation of the regulatory analysis is therefore warranted.
3.12
3.3.4 Value/Imoact Analysis tv acal evaluation of the proposed reg latory action results in a If the s
" No A cfou ciectnan e xclfr t may presume hat the substantial L'6 etermibation,4the ana ys favorabl The initiative additional protection standard of 10 CFR 50.109 is achievable.
should then be assessed in accordance with Section 4.3, " Estimation and Should the impacts not Evaluation of Values and Impacts" of these Guidelines.
be justified, further activities and analyses should be terminated unless there is a strong qualitative justification for proceeding further.
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3.13