ML20056E613
| ML20056E613 | |
| Person / Time | |
|---|---|
| Issue date: | 07/06/1993 |
| From: | Rogers K NRC COMMISSION (OCM) |
| To: | Chilk S NRC OFFICE OF THE SECRETARY (SECY) |
| References | |
| NUDOCS 9308240337 | |
| Download: ML20056E613 (5) | |
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RE."ASED TO THE PDR
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NOTATION V0TEj g fg
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RESPONSE SHEET
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SAMUEL J. CHILK, SECRETARY OF THE COffiISSION FR0li:
C0l44ISSIONER ROGERS
SUBJECT:
SECY-93-167 - REGULATORY ANALYSIS GUIDELINES OF THE U.S. NUCLEAR REGULATORY C0l44ISSION APPROVED 4EN OISAPPROVED ABSTAIN Nor PARTICIPATING REQUEST DISCUSSION 1
C0!44ENTS:
The staff has made a significant improvement in the proposed regulatory analysis guidelines (Guidelines) over the earlier February version and I approve publication with the attached edits.
Regarding the Regulatory Analysis Technical Evaluation Handbook (Handbook), I believe that Chapter 3 should be revised to provide nore detail rather than to be identical to the Guidelines.
I also think, in line with Commissioner Remick's concern expressed in his March 12, 1993 memorandum, that it would be beneficial to include, as an appendix in the Handbook, the pertinent parts of the safety goal policy statement (i.e.,
qualitative goals, quantitative objectives) and the backfit rule, t
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I 3.1 Safetv Goal Decision Criteria NRC's safety goal policy addresses a level of acceptable residual individual i
risk from operatio pow r reactors ged to be lower h n that associated f(W !
Tho e ovo c uocn w 4 Ma bayo which l
with adequate pro t on.,Jf' adequate protection is -act yremc'd continued i
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operation would not be allowed. -As result,The safety goal 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 f
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.
4 As a result, relaxations or the elimination of requirements are not subject to i
the safety goal evaluation of this section.
In justifying a proposed backfit under the backfit rule, the burden is on the f
staff to make a positive showing that a generic safety problem actually exists f
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and that the proposed backfit will both address the problem effectively and provide a substantial safety improvement in a cost-beneficial manner.
3.2 Procedure j
j The staff must first determine whether the subject regulatory action needs to l
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 j
be done (Figure 3.1).
If the proposed regulatory action meets the safety goal l
l decision criteria, the regulatory analysis should include the results of the l
l 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 j
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
4 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 LOCA).
It should be noted that the safety goal decision criteria described here do T%t it,[ W p e4N 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) p 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 proposed 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
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FIGURE 3.2 SAFETY GOAL DECISION CRITERIA 1E -03 PROCEED TO V/I PORTION PROCEED TO V/I PORTION OF OF REGULATORY ANALYSIS REGULATORY ANALYSIS
- 1 (PRIORITY) n.
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1E-04 MANAGEMENT DECISION PROCEED TO V/I PORTION
=U WHETHER TO PROCEED OF REGULATORY ANALYSIS Mg WITH V/I PORTION OF mo REGULATORY ANALYSIS E$
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MANAGEMENT DECISION NO ACTION WHETHER TO PROCEED WITH 5
V/I PORTION OF REGULATORY 2
ANALYSIS Q
ESTIMATED CONDITIONAL CONTAINMENT FAILURE PROBABILITY **
- A determination is needed regarding adequate protection or compliance; as a result, a value/ impact analysis may not be apprci'ri 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 bare.
jgb The safety goal decision criteria discussed in these sections 4as been o
summarized 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 i
substantial additional protection would be achievable and whether continuation of the regulatory analysis is therefore warranted.
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3.3.4 Value/ impact Analysis l
V/A If the safety goal evaluation of the proposed regulatory action results in a
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getermi ation,,the anayfr ' No A cisas.) hat the substantial j
ciecaium e ve f avorabl (e = so yst may presume 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 l
there is a strong qualitative justification for proceeding further.
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