ML20154E457
| ML20154E457 | |
| Person / Time | |
|---|---|
| Issue date: | 09/12/1988 |
| From: | NRC COMMISSION (OCM) |
| To: | |
| References | |
| REF-10CFR9.7 NUDOCS 8809190002 | |
| Download: ML20154E457 (77) | |
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l UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
Title:
BRIEFING OF SEVERE ACCIDENT POLICY FOR FUTURE LIGHT WATER REACTORS Location:
ONE WHITE FLINT NORTH, ROCKVILLE, MARYLAND Date:
MONDAY, SEPTEMBER 12, 1988 PageS:
1-45 l
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Ann Riley & Associates Court Reporters 1625 l Street, N.W., Suite 921 l
Washington, D.C. 20006 (202) 293-3950 l
8809190002 800912 PDR 10CFR PT9.7 PDR i
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t DISCLAIMER This'is an unofficial transcript of a meeting of the United States Nuclear Regulatory Commission held 9-12-88 in the Commission's office at One on White Flint North, Rockville, Maryland.
The meeting was open to public attendance and observation.
This transcript has not' been rev'iewed, corrected or edited, and it may contain inaccuracies.
The transcript is intended solely for general informational purposes.
As provided by 10 CFR 9.103, it is not part of the formal or informal record of decision of the
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matters discussed.
Expressions of opinion in this transcript do not necessarily reflect final determination or beliefs.
No pleading or'other paper may be filed with the Commission in any proceeding as the result of, or addressed to, any statement or argument contained herein, except as the Commission may authorize.
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1 UNITED STATES OF AMERICA 2
NUCLEAR REGULATORY COMMISSION 3
4 BRIEFING OF SEVERE ACCIDENT 5
POLICY FOR FUTURE LIGHT WATER REA2 TORS 6
7 PUBLIC MEETING 8
9 Nuclear Regulatory Commission 10 One White Flint North 11 Rockville, Maryland 12 l't.
13 MONDAY, SEPTEMBER 12, 1988 14 15 The Commission met in open session, pursuant to 16 notice, at 2:00 p.m., the Honorable LANDO W. ZECH, Chairman of 17 the Commission, presiding.
18 COMMISSIONERS PRESENT:
19 LAN DO W.
- ZECH, Chairman of the Commission 20 TI'? MAS M. ROBERTS, Member of the Commission 21 XENNETH ROGERS, Member of the Commission 22 23
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STAFF AND PRESENTERS SEATED AT THE COMMISSION TABLE:
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3 S.
Chilk 4
W.
Parler 5
V.
Stello 6
E.
Beckjord 7
T. King I
8 9
AUDIENCE SPEAKERS:
10 11 L. Rubenstein r
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i 13 14 15 16 I
17 18 19 t
20 i
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21 22 a
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24 25
s.
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CHAIRMAN ZECH:
Good afternoon, ladies and gentlemen.
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2 Mr. Carr will not be present with us this afternoon.
The 3
Commission issaed its severe accident policy statement August 4
of 198S and this policy sta:ement provided the general guidance 5
for resolving severe accident issues for future and existing 6
nuclear power plants.
7 Today th?, Commission will be briefed by the Office of 8
Research on options for the implementation of the severe 9
accident policy for fut re light water reactors.
It's my
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10 understand!.ng that the proposed options being discussed today 11 would cover ccandardized designs currently under review and 12 also cover the 600 megawatt design currently included in the f
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13 Electric Power Research Institute, 1.PRI, advanced light water 14 reactor program.
15 The Commission recently issued a proposed rule on 16 design certification and I would be interested in hearing this 17 afternoon how the proposed options consider this proposed rule 18 and how thia activity relates to other severe accident 19 programs.
Additionally, the Commission vould be interested in 20 hearing if these proposed requirementa are consistent with any 21 industry activities in this area such as the EPRI advanced 22 light water reactor requirements document.
23 I understand there are copies of the viewgraphs at i
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24 the entrance to the mooting room.
Do any of my fellow 25 Commissioners have opening comments before we begin?
8 0
4 1
(No response.]
2 CHAIRMAN ZECH:
If not, Mr. Stello, you may proceed.
3 MR. STELLO:
Thank you, Mr. Chairman.
There's one 4
point that I think is very important to make at the outset and 5
that's the issue of how to treat severe accident issues for all 6
kinds of advanced reactors.
As you are aware, some weeks ago 7
we briefed the Commission on the advanced reactor DOE design 8
and attempting to write rules that would deal with severe 9
accident issues for those reactors would be significaatly 10 different than the kinds of rules we would see, would be proper 11 to put in place for the types of reactors that you mentioned in 12 your opening statement.
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13 We are not suggesting, nor would we even want to try 14 to limit the application of these rules in such a way where we 15 are trying to cover more than we can.
We're taking on a 16 limited set of the reactors as we see in the future and trying 17 to develop some guidance for the industry for that purpose and 18 for that purpose only.
I recognize that as other reactor 19 designs are proposed in the future pursuant to the Commission's 20 advanced reactor policy statement, thac different rules would I
21 be necessary or may be necessary, we can't even say for sure 22 that they would be, but clearly those in the DOE design would 23 be different.
24 So what we are trying to focus our attention on this
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4 25 afternoon is for those particular plants which we are already
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aware of for which there would be a need for guidance and it is l
2 those that we will be addressing this afternoon, and not the 3
broader question.
With that brief introduction and point, let 4
me turn to Mr. Beckjord who has some points.
We'll get right 5
on with the briefing with Mr. King in a moment.
6 MR. BECKJORD:
Mr. Chairman, the proposed 7
implementation of the severe accident policy for future light 8
water reactors addresses a number of considerations that have 9
ariaen since the TMI-2 accident.
But the end product of this 10 is simple and straightforward and consists of three elements 11 that are the end product of our recommendation.
12 First, a rule that implements the severe accident
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13 policy statement and requirss a probablistic risk assessment 14 for each plant that is proposed.
Second, a regulatory guide 15 that defines in detail what the purpose, the scope, and the 4
16 content of the required PRA is.
And third, a second regulatory 17 guide that defines the requirements for adequate technical 18 resolution of the TMI and the generic safety issues that have 19 arisen.
With that, Mr. King.
20 CHAIRMAN ZECH:
Thank you very much.
You may 21 proceed.
22 (311de.)
23 MR. KING:
On Page 1 of the handout is the outline
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24 I'm going to follow today to briefly talk about the purpose of 25 the presentation today, some background information on the
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issue we're going to discuss.
The benefits of putting forth 2
guidance for future light water reactors in the severe accident 3
area.
The options considered for this guidance.
Conclusions 4
regarding the options.
The scope of the proposed guidance that 5
we recommend.
What I call some additional benefits of such 6
guidance and finally the schedule that we propose to follor.
7 (Slide.)
8 MR. KING:
On Page 2, briefly tho purpose of the 9
presentation.
It's to brief the Co-raission on the staf f's 10 proposal as presented in SECY 88-248, for implementation of the 11 severe accident policy statement fcr light water reactors.
12 This also corresponds to Item 10-A in SECY 88-147, which is the 13 integration plan for closure of severe accident issues.
And in 14 the longer term, there's also a followup to an older SECY 15 paper, SECY 86-76, back in February of
'86, which was the first 16 paper that dealt with the implementation plan for the severe 17 accident policy statement.
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18 (Slide.]
19 MR. KING:
On Page 4, by way of background.
The l
20 current regulations do not require plents to cubmit a PRA, 21 probabilistic risk assessment, or assessed for severe 22 accidents, except for a few specific areas where the rules do 23 address some severe accidents such as the ATWS and the station I
d 25 (Slide.)
i 1
1 MR. KING:
As a result, the commission issued the l
2 severe accident policy statement in August of '85, which 3
provided general guidance for resolving severe accident issues 4
for future and existing reactors.
As a result of this policy 5
statement for existing reactors, the staff is developing 6
guidance for an individual plant examination process to address 7
severe accident issues.
Future reactors, the policy statement 8
directed that one technical resolution of the TMI items, 9
unresolved safety issues, medium and high priority generic 10 safety issues be demonstrated with special emphasis on the 11 reliability of decay heat removal in electrical power systems.
12 (Slide.)
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13 MR. KING:
It went on to state that a probabilistic 14 risk assessment should be completed on future plants, including 15 consideration of severe accident vulnerabilities and directed 16 that the staff issue guidance on the form purpose and role that
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17 PRA's are to play in severo accident analysis and decision l
18 making for both existing and future plant designs.
That would 19 include the minimum criteria of adequacy that the PRA's should 20 meet.
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21 (Slido.)
l 22 MR. KING:
The policy statement also stated the i
23 Commission's expectation that new standard or custom plants i
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24 will achievo a higher standard of severe accident safety l
t 25 performanco than the prior designs.
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8 1
(Slide.)
2 MR. KING:
Therefore, the question that the staff has 3
addressed in our SECY paper and in today's presentation is what 4
form and content should such additional guidance take and how i
5 should the expectation of a higher standard of severe accident 6
safety performance be ensured.
Later in the presentation, I 7
will summarize the options considered in the staff's 8
recommendation, and also the staff's recommendation itself.
9 (Slide.)
10 MR. KING:
On Page 8, we talk about related industry 11 efforts.
It's important to taention that industry has been 12 actively involved in the severe accident area and has been f
's 13 attempting to address severe accident concerns for future LWR's 14 for several years and is in the process of recommending 15 solutions to certain severe accident issues.
16 Two main areas in this regard are, one, the Electric 1
17 Power Research Institute's advanced light water reactor I
18 program, which is recommending design solutions to certain 19 severe accident concerns through the ALWR requirements 20 document.
And the Department of Energy industry cooperative 3
l 21 effort, called the advanced reactor severe accident program, l
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22 ARSAP, which is in direct support of the combustion engineering l
23 system plus stundard plant application which is currently
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24 before the staff for review.
25 In addition the other standard plants applications, i
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1 the advanced boiling water reactor and the Westinghouse SP/90 2
are also proposing solutions to selected severe accident 3
concerns as part of the review of their designs.
4 With these activicies in mind, we held a workshop in r
5 June of this year to explore with the industry and the public 6
the need for rdditional guidance in the severe accident area.
7 As a result of this workshop, ther.s was a strong consensus that i
8 guidance from NRC is desirable.
However, there were varying 9
opinions as to the form and content this guidance should take.
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10 (Slido.)
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11 MR. KING:
On Page 9, I'd like to summarize, l
12 beginning on Page 9, the benefits of such guidance and what I g.
1 13 believe are the reasons there was such a consensus both among 14 the staff and the industry as to the need for such guidance.
l 15 These could also be thought of as objectives of any guidance f
16 that we would put forth.
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17 First, such guidance, we believe, would clarify j
i 18 Commission requirements and expectations for the treatment of i
19 severe accidents on future LWR's, which would be valuable to
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20 both the industry and the NRC staff reviewers.
We believe such 1
21 clarification would promote stability in the design, licensing, i
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22 and operation of new plants by making licensing requirements i
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23 predictable.
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24 (Slide.)
25 MR. KING:
Continuing on Pago 10, we believe the 1
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guidance would codify current staff treatment of severe 2
accidents in the ongoing standard plant reviews and putting 3
forth such guidance will help avoid having to litigate savore 4
accident requirements at each licensing hearing, whether it's a 5
design certification hearing or a custom plant hearin7.
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6 believe that will feuilitate the hearings and in the long run 7
would save staff resources.
8 (slide.)
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MR. KING:
Finally, we believe the guidance will help 10 ensure that enhanced safety is achieved through elimination of 11 significant severe accident vulnerabilities including those 12 vulnerabilities that have been discovered through our past f"
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13 experience, through the probablistic risk assessments that have i
14 already been completed, and through the research programs that 15 have been going on for several years.
16 (Slide.)
1 l
17 MR. KING:
Beginning on Page 12, t%e options that we l
18 considered for putting forth such guidance.
Basically, we h
I 19 considered four options.
Generally, these options had 4
20 increasing specificity in the rule when going from options one i
21 through four.
The first option we considered was to utilize 22 what's already available in the proposed 10CFR Part 52, the I
23 proposed rulemaking on early cite permits design certification f(
24 and combined licenses.
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25 If you recoil, Part 52 has some general words in it.
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r 3
o 11 1
I will just quote them since they're very short.
It requires
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2 applications to include a design-specific probabilistic risk 3
assessment, together with a consideration of any severe 4
accident vulnerabilities that the PRA exposes and a realistic l
J assessment of the degree to which the design conforms to the l
l Commission's safety goals for plant operations.
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1 7
Our option one would utilize those words and devJlop 8
some reg guides to describe, provide additidnal guidanco on the f
9 content of the PRA and the severe accident assessments and 10 acceptance criteria that would be required to meet those, that 11 general words in Part 52.
i 12 (Slide.)
i i
The second option is on Page 13.
That 14 would be a general rule or rules.
It would require a PRA and a i
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15 severe accident assessment.
It would be directed toward
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16 identifying and correcting significant vulnerabilities j
17 resulting from the severe accident assessment.
It would cover k
1 18 both severe accident prevention and mitigation.
The words in I
l 19 the rule would be more specific regarding the intent of the
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20 severe accident assessment than the words that are currently in
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21 the proposed Part 52.
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1 22 Again, there would be reg guides to provide l
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l 23 additional guidance on an acceptable way to meet that rule.
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24 One item in option two which I should emphasize is that the l
l 25 primary acceptance criteria in option two would be a cost l
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benefit, on a cost benefit basis.
We're looking at
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2 vulnerabilities and determining whether something needs to be 3
done about them.
4 (Slide.)
5 MR. KING:
Page 14 is options 3 and 4.
Option 3 is 6
basically the same as option 2 in terms of the Rule, except the 7
Reg Guides would -- acceptance criterion in the Reg Guides 8
would not be based soley on cost benefit analysis.
They would 9
require future designs to resolve any significant severe j
10 accident concerns identified to date through our previous 11 experience, PRA assessments and R&D programs.
They would also 12 require an assessment for vulnerabilities unique to the design r
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13 through the PRA.
14 option 4 is what we call the prescriptive rule.
The 15 rule itself would have more detail in it concerning the severo 16 accident assessment and the acceptance criteria than any of the l
17 other three options.
That's the primary difference between a
18 option 4 and the other options.
These four options are really i
19 four basic concepts for putting forth guidance.
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20 The exact nature of what would go into the Rule and I
21 the Reg Guides in either of these options, would certainly have 22 to be decided when the technical work is completed.
We're not 4
I 23 prepared today to propose exact Rules or Reg Guides.
You might l
24 ask, why isn't there an option 5, which would be, do nothing
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25 now -- address severe accidents on a case-by-case basis in the i
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individual licensing actions.
We believe that the k-2 direction in the severe accident policy statement and the 3
benefits of putting forth such guidance at this time --
4 additional guidance beyond the policy statement have such l
5 advantages that we did really not consider -- seriously 6
consider an option that says do nothing else beyond the policy 7
statement at this point.
8 (Slide.)
9 MR. KING:
On page 15, conclusions regarding the 10 options; Options 2 and 4 are not believed to be attractive inc a
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11 comparison to 1 and 3, for the basic reasons that option 2 has i
12 heavy reliance on cost benefit analysis.
Guidance for
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13 application of cost benefit analysis to future reactors, needs 14 development and we're afraid that even if it developed, there
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15 is a potential for -- using cost benefit in the acceptance i
I 16 criteria, relying heavily on it; thoce's a large potential for
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17 diverting attention to pencil-sharpening numbers and not really 18 solving the problem.
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l 19 Option 4, the prescriptive rule -- we're concerned J
l 20 that it limits flexibility.
Wo believe that putting details in L
j 21 the Reg Guide allows more flexibility to update the guidance to 22 account for new information.
It's in the framework and intent I
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23 of the rule.
Option 4 would take a step in the wrong direction j
j 24 in allowing this flexibility.
Therefore, we do not consider it 1 (
25 one of the favorable options.
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14 1
(Slide.)
2 MR. KING:
Option 1, which is reliance an the words n 3
the proposed 10 CFR 52, is workable, however, we feel it has 4
some dicadvantages, i
5 (Slide.)
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MR. KING:
The Rule itself, the words in the Rule 7
itself, lack focus on the importance of severe accidents in 8
future reactor designs, and lacks focus on the intent af what 9
we're trying to achieve with this proposed rule.
10 The words emphasize the procedure aspects and not the 11 parformance requirements.
Right now, the way 10 Cix 52 is r
12 worded, those words would only be applicable to designs wh1 f(
13 utilize 10 CFR 52 in the licensing process.
Custom plants, or 14 plants not utilizing the one-step licensing options, would not t
15 be covered.
16 (Slide.)
17 MR. KING:
Page 18, Option 3 -- we believe that i
18 Option 3 provides all the benefits that I mentioned earlier in f
t 19 the presentation and appears to be stronger than the other 20 options, in that the Rulo more specifically addresses the t
21 severe accident concerns by documenting the purposes and intent 22 of the severe accident assessments in the rule, yet maintaining
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23 flexibility by putting the details of the assessment in the l
24 acceptance criteria and Reg Guides.
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25 it is applicable to all standard and custou LWR i
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applications.
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i 2
(Slide.)
3 MR. KING:
Therefore, our recommendation is to pursue 4
Option 3.
5 (Slide.)
6 MR. KING:
On page 20, to summarize the scope of th l
7 guidance that we have in mind under option 3, as Mr. Stello p
8 mentioned, the proposed Rules and Regulatory Guides would be 0
limited to LWR designs not significantly different than current t
10 generation LWRs, such as the three large standard plant F
1 11 concepts that are currently under review, as well as the 600 12 megawatt electric smaller plants currently included in EPRI's l
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13 ALWR program.
i 14 We believe that for designs such as these, the severe
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d 15 accident issues are sufficiently known to allow us to develop j
i 16 detailed guidance at this time.
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17 (Slide.)
f 18 MR. KING:
Guidance for LWR designs is significantly j
19 different than current generation LWR designs, would be t
i 20 developed later under our proposal -- only after consideration l
r 21 of the unique attributes of those designs, so as not to inhibit 22 innovation of designs that are much different than what we know 23 of today.
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24 The guidance to be developed by the staff will 25 consist of a general Rulo or Rules an supporting Regulatory t
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16 1
Guides which will do the following.
/
2 (Slide.)
3 MR. KING:
Beginning on page 22, what we envision 4
will be an update of the existing 10 CFR 50.34 (f) to make it i
5 applicable to future LWRs, and would include a requirement for i
f 6
future LWR designs to do and submit a PRA, a well as to 7
demonstrate technical resolution of unresolved safety issues, 8
high and medium priority generic safety issues and the TMI l
d 9
action items.
i 10 This assessment and update of 10 CFR 50.34(f) would
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11 also include an integrated look at other parts of 10 CFR 50 to 12 ensure consistence and appropriate applicability of future 13 LWRs.
The guidance would require severe accident i
14 vulnerabilities be assessed on future plants, including l
l 15 specifically addressing those severe accidents events and l
i 16 phenomena judged from previous experience to be of significant
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i 17 risk.
I 18 (Slide.)
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19 MR. KING:
It would also provide guidance on
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t 20 acceptance criteria, however, we do not envision that this I
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21 acceptance criteria will not prescribe design solutions.
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1 22 (slide.)
i 23 MR. KING:
It will involve an assessment of severe
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I 24 internal and external events, and will build upon and utilize
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t 25 products of other ongoing and related programe as much as much 1
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as possible.
For example, what's going on today in the f\\
2 individual plant examinations, as well as the information we're 3
receiving through the EPRI and the ARSAP programs.
L 4
(Slide.)
5 MR. KING:
On page 25, it's important to note that we 6
do not view this effort as changing the definition of the l
7 adequate level of safety for reactors.
This is not an attempt h
8 to change the current definition of the design of basis of l
9 reactors.
Rather, it is viewed as e muring safety enhancement 10 through increased margin for severe accidents, which we believe l
11 was consistent with the Commission's severe accident policy l
l 12 statement to expect future designs to achieve a higher standard
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13 of severe accident safety performance.
14 on this particular point, any views the Commission 15 has, we would certainly be interested in hearing.
16 (Slide.)
17 HR. KING:
on page 26, we had attached to the 18 Commission paper, to the SECY paper, some draft Rules and Reg 19 Guides.
I wanted to point out that these are really examples 20 to illustrate the scope and depth of the kind of guidance we're l
21 talking about for these Rules and Reg Guides.
They're not 22 intended to represent any final wording at this point.
We 23 still have a lot of work to do in this regard, and we come back 24 with final wording, as you can see when we get to the schedule.
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25 I mentioned earlior some additional benefits in
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addition to doing PRA and assessing for severe accident t
2 vulnerabilities, we believe that requiring future plants to do 3
a PRA and do the severe accident assessment, may help identify 4
and preserve other assumptions that are related to safe 5
operation.
6 (Slide.)
3 I
7 MR. KING:
Page 28 lists some examplos of these.
For 8
example, in doing a PRA, various assumptions are made regarding 9
operators taking action regarding equipment qualification and 10 so forth.
What our assessment, what our requirements would i
11 involve, would be, the designer would have to keep track of 12 these items, these assumptions and document these to assure i
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13 that they find their way into the final plant design and into 14 the final operation and maintenance at the plant.
15 (Slide.)
1 16 MR. KING:
Page 29, regarding schedule -- schedule i
17 for developing guidance is presently driven by the schedule for 18 review of the three evolutionary standard reactor designs now l
19 under way.
The Westinghouse SP/90, GE's ABWR and the CE System 20 80+.
l 21 We want to have these Rules and Reg Guides in place i
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22 to support the first design certification hearing which is now 23 scheduled for approximately mid-1990.
24 To facilitate the standard plant reviews, and to
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25 avoid last minute impacts on these reviews, we plan to work
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closely with NRR on the development of these Rules and Reg
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i 2
Guides, as well as provide several opportunities for public l
3 ar.d industry involvement in the process via workshops.
r 4
These would be in addition to the formal public 5
comment process that such Rules and Reg Guides would go I
6 through.
t 7
(Slide.)
8 MR. KING:
On the last page, we have developed a 9
schedule, so as to have the Rule making and Reg Guides 10 completed, prior to the start of the design certification, as l
l 11 Well as providing for two workshops.
Basically, for the r
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12 proposed Rule, we would hope to have proposed Rule for your A'
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13 review ist May of 1989, and the ff.nal Rule in March of 1990.
14 In summary, what would be provided on these j
15 schedules, would be a proposed Rule change and two Rr,gulatory 16 Guides, as we view this activity right now.
That completes my
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I 17 presentation.
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i 18 CHAIRMAN ZECH:
Thank you very much.
Questions?
Mr.
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J 19 Roberts?
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l 20 COMMISSIONER P0BERTS:
No questions.
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21 CHAIRMAN ZECH:
Mr. Rogers?
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j 22 COMMISSIONER ROGERS:
Well, yes.
I have a couple of
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23 questions about some things I'm not too comfortable about.
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24 With respect to the use of the word, "prescriptive 25 rule," it seems to me we're using it in a little different l
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sense than the way we have been using it recently in talking t
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2 about, for example, a maintenance rule.
3 In that instance, proscriptiva means relating to 2
4 detailed procedures that the licensees have to follow.
- Here, 5
it seems to me, we talk about flexibility in connection with 6
the prescriptive rule, but the flexibility, if I understand l
7 what I've heard and seen in the documentation so far, is for 8
ourselves -- not necessarily flexibility for the licensee or j
I 9
the designer.
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10 In fact, I'm concerned that the approach that we seem 11 to be taking here, if I understand it correctly, could in fact, 12 give some significant problems to designers, if there is if that flexibility relates to a evolution of requirements or f
13 s
14 not requirements, but essentially requirements in Ragulatory i
15 Guides that evolve during the time that the designs are going l
i 16 on.
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17 So, I am uncomfortable with what I normally am l
j 18 comfortable with -- namely, a less prescriptive approach, j
i 19 because it.eems to me that we are ducking the job that has to t
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20 be done which is to set the performance objectives that the l
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4 21 designs cust meet, and allow the flexibility to the designers l
22 as to how they are going to meet them.
f i
i 23 So, it seams to me in looking over the materials,
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t 24 that we nay not know what those performance objectives are.
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25 We're leaving ourselves the flexibility to find cut what we 1
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think they should be, and then to put them out in the form of a i
2 Regulatory Guide.
3 My concern is if this is in fact what we are 4
proposing to do here, that we seem to be perpetuating the 5
problem which has existed for a long time, namely, that we are 6
changing the standards which we expect licensees to meet, or 7
those people who are designing plants for licenses.
8 So I am uncomfortable by what we mean by flexibility 9
here because it seems to me that the flexibility relates to a 1
10 lack of our readiness to be prescriptive in terms of specific 11 objectives that have to be met.
So I would like you to comment 12 on that because I think that is a very fundamental question as i
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14 One big question mark in front of me is are we ready 15 to do what we are saying that we want to do now?
Are we really i
16 ready to proceed?
I would like to know to what extent options 17 three and four, for example, have been dircussed with the 18 industry and DOE people who have been concerned with the ARSAP 19 program.
20 I know you have had talks with industry, you have had 21 a dorkshop, but the question is what did you talk to them 1
22 about? Thuy asked for guidance and definition, and have you i
i 23 gotten any response back on now the form that that guidance and F
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24 definition is beginning to take insofar as it relates to the 25 options that have been developed here for consideration, or did
22 1
the discussions with the industry people precede that
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2 formulation in your own minds as to what the options might be?
3 I would like to hear that.
I have the impression 4
that perhaps these options had not by themselves been 5
discussed. I think that the industry has asked for guidance and 6
specificity so they know what the ground rules are that they l
7 have to operate under in terms of designing something, and I am 8
uncomfortable if we are not ready to do that but we want to 9
start to go down the road of a process which would define those i
10 things through regulatory guides rather than thrcugh really i
11 putting out the rule with the objectives that have to be not.
l 12 I am not for our trying to dictate how a plant should g-13 be designer?, but I am very much in favor of our coming to a s.
i 14 clear definition of what we expect designers to meet and not to 15 let that float out to be defitted later on through a collection 16 of changing regulatory guides.
17 So I would like to hear your comments on that.
I 18 would also like to have a question for the general counse and 19 that would bei What would be the status of a regulatory guide 20 that is referenced in a rule?
Regulatory guides we can change.
21 There is some process.
I'm not sure I understand or know what 22 it is, but I understand that we can do it and that it is easier l
t 23 to do than to chang a rule.
If we reference a regulatory guide l
24 in a rule, does that make it as difficult to change that
(
25 regulatory guide as it would be to change the rule, so that l
e o
23 I
referencing a regulatory guide in a rule might not give you the 2
flexibility that you are looking for to change the rag guide?
3 I would like to hear something from general counsel 4
on that question, either now or some other time.
l 5
MR. PARLER:
I would be glad to respond now.
We do 6
have somewhat of a parallel to the question that you put l
7 already in the sections in Part 50, where the Part 50 sections t
8 refer to various code requirements.
As those code 9
requirements change from time to time, the regulation has to be 1
10 changed, so if something is referenced in a regulation, in 11 order to change it and update it you would have to change the 12 regulation.
13 If I ray, sir, a different question that is, at least 1
j 14 in my judgment from the legal standpoint, a more serious 15 question is whether the reference in a regulation to a s
16 regulator guide legally changes the regulatory significance of 17 the guide.
Under our approach to licensing and regulation, 4
j 18 regulatory guides generally are simply that.
They are one 19 approach to follow in oraer to satisfy the staff's 20 requirements.
21 If an applicant or a licensee wants to follow some 22 other approach, it is free to do so. In other words, they are 23 suggestions.
Guides are suggestions. Now, it is not clear to 24 me that one can simply by referencing a regulatory guide in a
['
25 regulation have tea regulatory or the rule advantages of a i
i
, ~.. _ _ _ _ _.
._.____.___,m_.
. _ - _ _ _ - = _ - - -,.
24 1
guide that would not otherwise be present.
You can probably 2
tell from my response that there would certainly be 3
considerable uncertainty unless the statement of considerations 4
makes it quite clear what we were trying to accomplish.
5 I will reflect on it further, and if I have any other 6
thoughts on the subject, I will advise you and your colleagues, 7
sir.
8 COMMISSIONER ROGERS:
If I could get your responses 9
on some of those questions.
I have got sote others, and I 10 don't want to just add them to the list.
11 MR. KING:
I will try and address the ones you asked.
12 COMMISSIONER ROGERS:
Yes.
[t 13 MR. PARLER:
Discussion with the industry of the 14 options.
At the June 1988 workshop, we did discuss these four 15 options with the industry.
16 COMMISSIONER ROGERS:
You did.
17 MR. KING:
There was no consensus in favor of any one 18 option.
There was a consensus against Option 4.
We had other 19 parties, varying views on the first three options, some in 20 favor, some against. So we took that information and we heard 21 some suggestions as to how these rules and reg guides should be 22 structured, and we factore that in into our recommendation for 23 Option 3.
(
24 Your problem with Option 3 is you are worried that 25 maybe it doesn't define the performance objeacives.
I think
25 1
the intent is that it does define the performance objectives.
(
2 The question is do you put those performance objectives in the 3
rule or in the reg guide?
Under Option 3 we have a general 4
statement as to the performance objectives would be in the 5
rule, but the specific objectives themselves would be in the 6
reg guide.
7 Under Option 4 it would be the other way around.
The 8
specific performance objectives or acceptance criteria would be 9
in the rule itself.
10 COMMISSIONER ROGERS:
Could ve have some examples of 11 exactly how that would translate into a statement?
I have a 12 little trouble visualizing exactly what we are talking about k
13 here when we talk about these objectives.
How specific would 14 they be?
Would they be numerical numbers?
Would they be --
15 what would they be?
16 MR. KING:
I can give you our current thinking.
We 17 have not nailed everything down at this point as to what those 18 would be or how many there would be.
Right now we are thinking 19 of three basic areas that th6se acceptance criteria or 20 performance objectives would fall in.
We know from past PRAs 21 and experience there are a number of items, phenomena or event 22 sequences that are of concern in the severe accident area.
23 Direct containment heating is an example of one.
{
24 We would require that this reg guide would list those 25 items that are of concern that we know about today and require
26 1
future plans at riress those in their designs.
In other words,
(
2 don't send in tomorrow's designs with today's problems.
The 3
acceptance criteria that we have in mind would be, one, that 4
there would be a design solution to the problem and that the l
5 PRA would have to show that that problem is no longer a 6
significant contributor to risk.
7 At this point we haven't decided whether we would tie 8
a probability number or risk number to that, but that in i
9 essence would be the thrust of the performance criteria or 10 acceptance criteria.
11 The secondary is the unique vulnerabilities to the l
12 plant.
These are different designs in some areas.
The PRA
((.
13 would be directed toward looking for the unique features of 14 that plant that could have some severe accident 15 vulnerabilities, and some acceptance criteria would be set up l
J 16 as to whether you need to do scmething about that vulnerability 17 or not, l
18 What we had in mind was an approach -- maybe a l
19 parallel would Le how we prioritize generic issues -- to look 20 at the contribution to risk, look at the potential person rem f
21 dose that you could get from such an event sequence versus 22 potential solutions to that problem in terms of their cost, and 23 you have some decision criteria that would tell you whether you
(
24 need to do something about that vulnerability or not do 25 something about it, just like we do today on generic issues, l
27 1
whether we do something about it or not do something about it.
(
2 The third general area is one of documenting the 3
assumptions that are made in the PRA, operator actions, 4
equipment qualification and so forth.
l 5
So those are the three areas that we have in mind 6
that would be performance or acceptance criteria.
Again, there 7
is a lot of work to be done yet in this area to nail down 8
exactly the specific list of those and the specific set of l
9 acceptance criteria.
10 COMMISSIONER ROGERS:
I noticed in Enclosure 3 of 11 SECY 08-248 there are some sample performance oriented 12 requirements, and there are no numerical values there.
There 13 is a statement that ends up by saying neither the single nor 4
14 multiple failures have more than a very low likelihood of 15 resulting in severe core damage.
16 MR. KING:
That's right.
17 COMMISSIONER ROGERS:
How is that to be interpreted?
l i
18 How is the very low likelihood to be interpreted?
1 19 MR. KING In the Reg Guide we would have to put down 20 what that means.
At this point we are not sure whether that 21 should be defined in terms of a risk number or a probability 22 number or should be defined in terms of a relative importance 23 to the overall risk picture of the reactor.
24 The problem with putting probability numbers or risk
(
J 25 numbers in the rule is that there is a certain amount of I
28 1
uncertainty when you do a PRA.
It is still an evolving art.
k-If you start putting numbers in the rules, in the reg guides, 2
3 how locked in are you to rigorously demonstrating that you need 4
that number?
We have a concern in that area.
We don't want to 5
get ourselves in a box trying to demonstrate a number that has 6
a lot of uncertainty associated with it.
We would rather use 7
the PRA and the severe accident assessment in a more 8
qualitative sense and a more relative sense to look for these 9
vulnerabilities and set our decision criteria in a more 10 qualitative sense, and then putting specific core melt numbers 11 or whatever numbers you want to put in.
12 COMMISSIONER ROGERS:
If you ultimately do come back f
i 13 with some numbers and they are in reg guides and they do take 14 on a status that approaches what would be in a rule, you've 15 done it anyhow.
So start changing those numbers, then you're 16 back in to the moving target problem for the designer.
17 MR. KING:
Our intent wJuld be, by tne time this 18 process is completed, by the time we reach March of 1990, that 19 we would have the performance criteria nailed down. Whether 20 they're in a rule or whether they're in a reg guide or some 21 combination, they would be nailed down.
It would stop being a 22 moving target at that point.
The reason we prefer a reg guide 23 is beyond March of 1990, there will still be other designs 24 being worked on.
We will not have looked at all the designs
{
25 yet.
There will stil. be some research results coming in.
29 1
If we get soma new piece of information that could 2
effect some of those criteria, it's easier to fold that into 3
the reg guide than into the rule.
But the intent would be to 4
not have a moving target.
The int 6nt would be to pin things 5
down as best we can by March of 1990, whether it's in a rule or C
a reg guide or a combination.
7 COMMISSIONER ROGERS:
That March of 1990 date, now, S
can you just once again tell me, I know you did tell me -- tell 9
us where that came from.
I know it came from the three designs 10 that are up in front of us now, but all of them, one of them --
11 12 MR. KING:
One of them would be advanced boiling 13 water reactors, under current schedules, would be the first one m
14 to proceed into a design certification hearing.
On current 15 schedules, that's the mid-1990.
We chose March of 1990 to 16 provide a proposed rule and reg guides to the Commission, and l
17 that would allow two months for review and comment prior to 18 formally issuing it as a final rule.
The intent would be to 19 have the final rule on the street before the design 20 certification hearings begin for that first plant.
21 COMMISSIONER ROJERS But the design has got to be 22 pretty well locked up well before that then.
23 MR. KING:
That's correct.
We have to work over this I
l
{
24 process, from today right through to mid-1990.
We have to work 25 closely with NRR and with the applicants.
That's why we have I
J J
i m
m
30 1
two workshops scheduled in our proposed schedule, as well as
(
2 the formal public comment process.
And regular interactions 3
with NRR so they know what the current thinking is, they can 4
factor that into their reviews.
It has to be a very closely 5
coordinated effort.
6 COMMISSIONER ROGERS:
I would like you also to say a 7
little bit more about the statement that's in the SECY on Page 8
7, and it's mentioned here, because the language seems to be a 9
little bit aifferent than what we've heard here, from what was 10 in the SECY.
And this has to do, this paragraph, the second 11 one from the bottom on page 7 of the SECY that says we also do 12 not propose to redefine the required level of adequate 13 protection for light water reactors as compared to existing l
14 plans.
Then there's -- some words go along with that.
And yet c
15 the last sentence of the paragraph says such an assessment will l
4 j
16 help ensure that that significant vulnerabilities to severe 17 accidents are identified and that future reactors provide 1
i 18 enhanced safety, consistent with the Commission's severe 19 accident policy statement.
j 20 I'm a little uncomfortable with whether we're saying r
21 on the one hand we're not redefining anything, on the other 22 hand we are.
That we're looking for something beyond what 23 we've looked for in the past.
The severe accident policy i
24 statement does express an expectation of a higher standard of j
f 25 severe accident safety performance without defining exactly 5
i
-O i
31 1
what that is.
But it says there's an expectation of a higher
(
2 standard and so how do we square thac with the statement that 3
ve don't propose to redefine the required level of adequate 4
protection for future light water reactors.
It seems a little 5
bit to me as if we're contradicting ourselves here.
6 MR. KING:
We started with the words in the l
7 Commission's policy statement to state an expectation to 8
achieve a higher level of safety.
Did not state it as a j
9 requirement.
10 COMMISSIONER ROGERS:
The difference is between an 11 expectation and a requirement.
Is that --
[
t 12 M. KING:
We looked at the words in the Commission's j
13 policy as wanting an assessment to be made of severe accidents, t
14 wanting significant vulnerabilities to Le fixed.
By that 1
15 process, an enhanced level of safety would be achieved.
That 16 it wasn't coming out and requiring adding, for example, to the i
17 design basis accident envelopes some set of severe accidents.
4 r
18 So the process we chose to s.citieve that was the one in this i
f i
19 paper and the words we have in here.
Again, it's the way we i
I 20 interpreted the words in the commission's policy statement.
Wo 21 were not proposing an addition of new accidents to the set of 22 what we already call the design basis accident spectrum.
l 23 COMMISSIONER ROGERS:
Well, yes, but then what is the l
2
] {
24 meaning, and I'm not badgering you, I'm just trying to get this j
25 out on the table because it seens to ne that we're moving and I i
t I
i 32 1
think probably in the right way, but we're doing it by saying
[
(
2 we're not moving.
And so I feel a little uncomfortable about -
)
3
- adrift here along a certain direction without recognizing l
i
~
that's exactly what we're doing.
And I, for one, would be 4
5 perfectly happy to go on the record of endorsing that we are, 6
in fact, looking for a higher standard of severe accident l
t 7
safety performance.
That we really mean that and whatever it l
l I
8 takes to pin that down.
But building pieces of that statement J
9 in at the same time dragging along with us the baggage of a l
I 10 statement that says that -- that omits that.
11 MR. STELLO:
In the two docur.dnts that are already j
12 now part of what we're trying to implement, the commission's i
g(*
13 advanced reactor policy would certainly suggest an expectation t
i 14 that future designs will have improved safety.
The severe 15 ac.ident policy statement I think states that the current t
16 gencration of current operating reactors are safo.
But in i
j 17 dealing with the issues that come out of severe accidents, you
'e will even cause safety to be advanced or to be improved.
And i
i 19 it is that policy which is being implemented which produces 20 that very problem that you raised.
We are, and the commission f
21 has not proposed in its advanced policy to redefine the level I
4 i
22 of adequate protection, but has suggested that there are ways 23 to look at severe accidents and implement those in a cost h
1 f
24 benefit way which will cause further anfety enhancements.
And
{
i 25 I think that is what we propose to do.
i
i P
33 1
CHAIRMAN ZECH:
Let me just state that EDO has I i
2 think stated the Commission views very well.
We discussed this 3
issue at some length when we made the severe accident policy 4
statement.
I think we worded it very carefully.
We did, l
5 indeed, expect improvements.
We did also state that we 6
believed the current reactors were operating safely and that 7
was an amportant conclusion I believe to state that.
8 And also though in expecting future reactors to 9
improve, we were careful not to lay a number on or a 10 quantitative number that would perhaps be unrealistic.
But it r
11 was clear and I think we've been consistent in the severe 12 accident statement and other statements along the same line j
13 that we expected improvements to continue.
And I think it was 14 worded very carefully, but also very clearly, I think, to show I
15 that improvement was expected.
But it was also recognized that 16 it was probably not appropriate at that time, at least to lay l
17 any kind of a more quantitative expectation on than just that, t
18 COMMISSIONER ROGERS:
Well, I would hope that somehow 19 we will come to a way to measure, some way, whether that l
l i
20 expectation is fulfilled or not.
Whether it's quantitative or 21 in some other way, but I think that a statement that has no way j
22 of being measured and determined whether it's satisfied or not, j
23 doesn't really have very much meaning to me.
So I hope we 4
24 would have some way of really measuring whether we've achieved I
\\
i l
25 something, j
i I
I 1
i
34 1
MR. MIZOGUCHI:
I think we're trying to measure, but
(
2 again we're being, at least I think, responsible in measuring 3
it in a qualitative way, but a realistic qualitative way that 4
does show improvement, and I think we can show improvements in 5
a very realistic sort of way, the things that we can measure.
6 But I do think that we were trying to again be realistic in not 7
trying to attempt to quantify with numbers something that 1
8 perhaps would not be appropriate to do at that time.
But I do 9
think we have been, again, consistent and encourtging in 10 expecting improvements, and I think frankly we're seeing those i
11 in the operating plants and I think in the advanced plants the l
12 designs that we're viewing and looking at, again, it's been my 1
4' i
(
13 impression that those words that we put in there have been l
]
14 respected and the proposals we're getting at least show an i
15 expectation of enhanced safety and that's exactly what we had 1
16 in mind.
17 COMMISSIONER ROGERS:
You always have the problem of 18 when you are on the margin, you know, is it enough?
19 CHAIRMAN ZECH:
It is always a judgment call, no 1
20 question about it, but I think we are trying to show that we 21 are expecting and encouraging and watching very carefully for 22 improved safety and I think we're getting it, personally.
4 l
23 COMMISSIONER ROGERS:
Well, I would just like us to j
{
24 be as clear on some of these matters as we can be.
25 CHAIRMAN ZECH:
I am just trying to say, I guess, l
l
35 l
1 another thing -- it is not the Staff.
It was a Commission i
2 decision.
It was our decision, our responsibility.
The Staff 3
is I think very faithfully carrying out what we gave them and 4
if we gave them words that were too vague or not appropriate, 5
it is our responsibility, so I just want to make that clear for l
6 us.
l 7
I know you were not here then, Commissioner Rogers, l
8 but the Commission did uake that decision and I think the Staff 9
is attempting ver'/ faithfully to carry out the Commission i
10 decision.
11 COMMISSIONER ROGERS:
Ac I said -- I am not beating 12 on the Staff.
I am trying to see that we know where we're i
p(-
13 going and we know once we've gotten there and that we have some 14 measures of those things.
15 CHAIRMAN ZECH:
We don't mind beating on the Staff l
l 16 when we think they're wrong but in this case I do think it was j
i 17 our decision and I think the Staff is again trying to carry out l
18 what we gave them and if we didn't give it to them in as l
19 definitive a way, then it is our responsibility.
[
I 20 But I can assure you that the Commissioneru j
[
21 themselves thought very carefully of these words and I I
22 perscnally at this time still think they were appropriate.
23 MR. STELLO:
Let me try to use two examples, and Tom, t
i 24 listen very carefully and if I get off track to let me know.
I l
{
1 l
25 haven't had time really to think about this, f
l
)
l c
l.
36
[
t 1
One of the issues -- dealing with the containment, we
(
2 know that that is an issue of uncertainty in how to treat an 3
existing plant.
As a matter of policy we would look for the 4
future to say that's clearly an issue we want disposed of.
In
}
5 a qualitative sense we now know we no longer have a challenge j
l 6
to the containment that we need to deal with it.
It's gone.
i 7
In terms of now measuring it, we have done a great i
8 deal of study using a number of PRAs to get quantitative 9
indication of what that would mean.
Qualitatively, yes, I I
10 think it's on its face, getting rid of that problem is very
}
11 wise to the extent you can and the extent to which that will l
u change risk I think we'll have some measures of that through
(
I f(
13 the PRA, which as a matter of policy we would also include in j
14 the regulation which would help do that.
15 So I think if you take that example, you could see i
16 how you could make very quickly a qualitative judgment of the
}
l l
17 advances and because you're going to require the PRA I think l
18 you will have some fairly good insights in terms of the l
19 quantitative assessments.
I 20 They're trying to work all that out right now, since f
I 21 we haven't done that work and to give you lots of specific j
22 examples I think it would be very difficult.
i 23 But I think I understand the concern you are raising 24 and we are mindful of that and then the commission wrote its l
{
l 25 backfit rule.
It says if we are going to backfit that we do in s
i 37 j
1 fact do ', cost benefit enalysis to make the assessment, is in j
t 2
fact the backfit warranted and when we make the assessment if j
i I
3 the particular rules, wnatever they are, to the extent that I
4 that is applicable, then we would be in fact making that t
l 5
judgment as best we know how to decide whether or not that s
6 particular rule ought to or ought not to stand or a specific l
7 requirement it it is imposed in a particular case.
3 8
MR. PARLERt Part of that rule, Mr. Chairman, is of f
4 9
course whether you are at the adequate level or at the margin
[
l 10 under the rule, as Mr. Ste11o I'm sure knows, but just for the l
t 11 record here, if you are talking about adequacy, you can't
(
)
l 12 consider the cost of the effort --
l f
i l (
13 CHAIRMAN ZECH:
That's correct and I'm sure --
j 14 MR. PARLER:
-- or one of the options approaches here i
)
f 15 would be irrelevant.
~
1 16 CHAIRMAN ZECH:
Yes.
I appreciate that.
I'm sure i
17 Mr. Stello does too.
l 18 MR. STELLO:
It is for that very reason that we made f
19 the observation that we do not plan to redefine in any way the 20 level of adequacy.
21 COMMISSIONER ROGERS:
I do not want to debate, turn 22 this into a big debate because I think we really ought to move e
23 along, but the language in SECY doesn't exactly say that.
It 24 doesn't say "adequate."
It says something else and I would l
{
25 like you to just review that agsin to see whether that's i
i I
l 38 i
exactly what you mean.
1 k-2 It doesn't refer to -- it says va do not propose to i
3 redefine the required level of adequate protection and so that i
i 4
could be interpreted a couple of ways, but I think we should 5
not pursue this to a great degree, except that if you lock at 6
the timetable of the schedule on which you have got to work, 7
you don't have an awful lot of time and if by the fifth month i
8 of 1990 you are going to be : ready to use something, you are I
9 going to have to come to some of those things that you are 10 going to put in the reg guides before then.
i 11 You just said that you would have to do that and I am 1
12 just wondering what is going to happen between now and then E
(
13 with respect to pinning down these measures because they will l
j 14 be in the reg guides, as you have told us that you will have f
15 ways of determining these things in the reg guides.
When will i
16 they start to appear and do you expect to ir. sue supplements to
{
17 the reg guides after 19907 i
)
I i
18 MR. KING:
Well, we would hope within six months from i
19 now to have the draft reg guide and rules in pretty good shape l
l i
l 20 and the process that goes on beyond that would be the formal f
'3 21 public comment process and then the formal process to get it 22 into a final rule and final reg guides.
23 We hope in the next six months the information that i
24 is lacking today, the basic technical information, will be in
(
}
25 place in a draft reg guido that NRR people will be aware of and f
I i
1
O O
39 1
through the workshops the industry will be aware of, so it
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2 won't come at the eleventh hour in the review with these j
}
3 plants.
4 Regarding supplements to the reg guides, our intent f
5 now is to make these reg guides and rules as complete as l
6 possible.
If some new piece of information comes up later on l
7 down the road, it could result in a supplement.
It is an l
8 mmbitious schedule, I would agree with you.
I 9
COMMISSIONER ROGERSt All right.
That you very much.
l 10 CHAIRMAN ZECH:
Well, let me just say I think that 11 the Staff has addressed this question very well but I am *ot i
12 frankly sure in my own mind whether we really need or whether i
l t
I (q
13 we really should have another rule on this subject at this i
r
)
14 time.
It seems to me that perhaps reg guides at least for now j
j 15 might be sufficient.
\\
16 Perhaps you could tell me what is the real impetus to r
l 17 get a rule in place and what is deficient about the rules we i
la have in place for severe accident at this time?
j l
f 19 MR. STELLot I think one very significant j
20 consideration is the fact that as we take plants that are in j
l i
21 the review process through the certification and rule-making, i
?
22 it would be very, very helpful to have these issues resolved to f
i 23 the extent we can by rule-making before starting the actual l
i 24 rule-making process or certification by rule-making of the l {
l 25 plants.
I
i 40 1
CHAIRMAN ZECH:
But I thought you pointed out earlier
(
2 whoa you mentioned that we're focusing on -- rather than near 3
term, if you will, advanced reactors and not the broader, 4
longer term --
5 MR. STELLC That's correct.
6 CHAIRMAN ZECH:
-- advanced reactors, as I understood 7
it.
So if that is the case, it we are really focusing on not 8
the real long range but the more naar term advanced reactors, 9
then is there not sufficient guidance already out and would not i
10 a reg guide be sufficient at this time?
11 MR. STELLO:
Yen, but it would cause these issues of j
12 how to handle -- because there is only a Commission policy 4^
13 statement on the severe accidents -- how to handle those issues s
i 14 would all be subject to part of the rule-making process for 15 each of the individual five plants -- I guess it is five or wix 16 cases that would be going through certification, or potentially i
17 through certification.
As you take each of those through 1
l 18 certification without the benefit of this rule, then by 19 definition all of those issues become issues which would be 20 potentially litigated in each and every case.
21 so by having a rule then you would eliminate or 22 reduce the amount of effort it would take to deal with these in 23 individual cases.
24 CHAIRMAN ZECHt Are we sure enough about the future
(
25 at this time to propose a rule?
j l'
41 1
MR. STELLO:
I am hesitant to ever say we are sure
(
2 about the future.
3 CHAIRMAN ZECH:
Just looking at the immediate i
4 future.
5 MR. STELLO:
In the plants we are looking right now, t
6 there are three of them which are in the review process.
We 1
7 have one for sure which we believe will go through s
certification, two others which I would classify as probably
[
9 and if the EPRI designs on the 600 megawatt level come forward l
t 10 I suspect that they too will go through the certification, j
11 So if they all go through it, then I do think it i
i 12 would be a big benefit to have it, but it is with those
}
\\
assumptions which I don't know how to deal with si.' ace we only
(
13 14 have as I understand it, confirmation of one certification.
(
i 15 Am I right?
16 CHAIRMAN ZECH:
Would you step to the microphone, 17 please, and identify yourself to the Reporter?
18 Thank you very much.
i l
l 19 MR. RUBENSTEIN:
Les Rubenstein, NRR.
L l
20 We have a formal request for the ABWR with their i
I 21 fairly rigid schedule to go through the design certification 22 process and we have also shortly behind that the combustion 23 plant.
Westinghouse's plant is currently in-house for a PDA f
24 and they have not -- although they have said they would be
(
{
25 submitting an FDA, they have not formally done so.
We also f
42 L
1 have indications that the two 600 megawatt plants would be I
2 coming in.
3 But formally in-house, in the final design stage, we L
4 have the ABWR from General Electric and the combustion plant.
i 5
CHAIRMAN ZECH:
Thank you very much.
6 MR. STELI4 One thought that just came to mind is 7
that we also need to deal with the potential possibility thst f
8 we may have custom plants.
If there is a need for building f
f 9
additional facilition and it arises in the near future, the l
10 next few years, clearly this would be of significant benefit I
11 for that purpose as well.
I 12 CHAIRMAN 2ECH:
Of course, we are open for
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13 standardized plants, not custom plants.
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14 MR. STELI4:
Yes, but I don't believe we have l
t 15 precluded.
I 16 CHAIRMAN ZECH:
Well, you haven't precluded it, but 17 it's going to be a -- going to have to make an awful hard case i
18 if they're other than standardized plants.
During the t
19 workshops, what was the views of the applicants?
Do they want 20 to propose -- do they want a rule?
f 21 MR. KING:
Yes.
All three applicants had l
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22 representatives there and it was unanimous that they did want l
23 to see guidance from NRC in the severe accident area.
I think
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24 they were pretty much unanimous and that they wanted to see the 25 rule to be as general as possible and allow them as much i
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43 1
flexibility as possible in terms of how you would address the
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2 various severe accident issues.
But it was unanimous that they 3
did want to see soma guidance come forth from the NRC.
4 CHAIRMAN ZECH:
And so the staff also agrees that a 5
rule is, should I say needed, necessary?
6 MR. STELLO:
Useful.
7 CHAIRMAN ZECH:
Useful.
But not mandatory.
8 MR. STELLO:
Not mandatory.
It is -- we could go 9
forward, and it is clear we could without a rule.
10 CHAIRMAN ZECH:
I guess my only concern is I just --
11 I can't get the feeling that we're really ready perhaps to make 12 the definitive judgments that are necessary for a rule.
I
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13 recognize the value if we could do tnat at this time.
14 Certainly that would be helpful, I think, and useful to us as 15 well as the applicants.
But I'm just not sure that from what 16 you've told us here today and what I read in this paper that i
17 we're really ready to do that and I must give it more j
18 reflection nyself before I can make such a judgment.
19 It seems to me that reg guides would indeed be 20 helpful, but I recognize that a rule is different from a reg 21 guide and has certain advantages.
Could you try to petsuado me 22 that you really need a rule or do you want to try to do that or 23 not?
How bad do you need a rule?
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24 MR. STELlot It would be useful, but not i
25 necessary.
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1 CHAIRMAN ZECH:
Okay.
That's good enough.
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2 MR. PARLER:
May I comment on that?
3 CHAIRMAN ZECH:
Yes, please.
4 MR. PARLER:
In order to answer a question like that, 5
at least from ny perspective, the answer may be assisted by l
I l
6 going out and getting the comments on a particular proposal.
i 7
Perhaps the proposal could sharpen the situation.
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8 CHAIRMAN ZECH:
I'm sure it could.
9 MR. PARLEkt The make a decision at that point.
f 10 CHAIRMAN ZECH:
Sure.
Of course, that's exactly the j
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11 approach to take.
My only question in my mind frankly was is i
12 it -- at this stage, is it even worth going out with a proposal L
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because of at least the uncertainty I sense about the readiness i
13 s
14 we are to put forward a proposed rule at this time.
I just --
15 I feel maybe we're not, but certainly I don't want to preclude l
16 anything and perhaps just putting something out for proposed l
17 comment would be useful and we would gather information that 18 would help us in that decision.
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19 But I guess in most proposed rules that I've seen 1
j 20 that we've put out so far, I've had a little more confidence l
i 21 that we're really ready to perhaps go ahead with it, and this l
l 22 one, I'm just not as confident that we have in hand the 23 wherewithal we really need to put out a proposed rule that 24 would be useful.
But I certainly would agree that the comments
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25 perhaps might sharpen up this issue and be helpful, but again, i
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I'm going to, myscif, have to reflect on it and decide what to k
2 do and I'm sure my colleagues will want to do the same thing.
3 Are there any other additional comments of any of my 4
colleagues?
5 (No response.)
6 CHAIRMAN ZECH:
Let's just say that we have been 7
asked by the staff to make a decision on the SEcY 84-248, and a
we've heard the staff's position, tr.d had the chance to 9
question them about it today.
As I say, it's currently not 10 clear to me that we're ready to do this yet, but I am going to 11 think about it more myself and ask my colleagues to do the same 12 thing.
Perhaps we can respond to the staff's request on this f'L 13 with a decision here in the near future.
14 If there are no other comments, thank you very much.
15 We stand adjourned.
16 (Whereupon, at 3:10 p.m.,
the briefing was 17 concluded.)
18 19 20 l
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24 25 l
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CERTIFICATE OF TRANSCRIBER l
This is to certify that the attached events l
of a meeting of the U.S. Nuclear Regulatory Commission
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entitled:
IMPLEMENTATIONOF SEVERE ACCIDENT POLICY FOR TITLE OF MEETING:
FUTURE LlGHT WATER REACTORS l
1 PLACE OF MEETING:
Washington, D.C.
(
DATE OF MEETING:
HONDAY, SEPTEMBER 12, 1988 I
were transcribed by me.
I further certify that said transcription is accurate and complete, to the best of my ability, and that the transcript is a true and accurate record of the foregoing events.
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1 lhPLEMENTATION OF i
SEVERE ACCIDENT POLICY FOR FUTURE LWRS t
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STAFF PRESENTATION TO COMMISSION SEPTEMBER 12, 1988 t
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PRESENTATION OUTLINE PURPOSE BACKGROUND BENEFITS OF GUIDANCE OPTIONS C0flS!DERED C0fsCLUSI0lls REGARD! fig OPTIONS SCOPE OF PROPOSED GUIDANCE ADDIT 10fiAL BENEFITS SCHEDULE 1
PURPOSE TO BRIEF THE COMMISS10f4 ON THE STAFF'S PROPOSAL ( AS PRESENTED If4 SECY-88-248)
FOR IMPLEMEt4 TAT 10N OF THE SEVERE ACCIDEl4T POLICY STATEf1ENT FOR FUTURE
- LWRs,
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CORRESPONDS TO ITEM LOA IN SECY-88-147 "INTEGRATION PLAN FOR CLOSING OF SEVERE ACCIDENT ISSUES."
3
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BACKGROUND CURRENT REGULATIONS DO'NOT REQUIRE PLANTS TO SUBMIT A PRA OR ASSESS SEVERE ACCIDENTS.
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SEVERE ACCIDENT POLICY STATEMENT 1
(50 FR 32138) ISSUED AUGUST 1985 PROVIDED GENERAL GUIDANCE FOR RESOLVING SEVERE ACCIDENT ISSUES FOR FUTURE AND EXISTING REACTORS.
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FOR Ex! STING REACTORS, THE STAFF IS DEVELOPING GUIDA14CE FOR AN INDIVIDUAL PLANT EXAMINATION PROCESS TO ADDRESS SEVERE ACCIDEN1 ISSUES.
FOR FUTURE REACTORS, THE POLICY STATEMENT DIRECTED THAT:
TECHNICAL RESOLUTION OF TKl/USl/GSIS BE DEMONSTRATED 5
J PRA BE COMPLETED, INCLUDING CONSIDERATION OF SEVERE ACCIDENT VULNERABILITIES.
THE STAFF !SSUE GUIDANCE ON THE FORM, PURPOSE AND ROLE THAT PRAS ARE TO PLAY IN SEVERE ACCIDENT ANALYSIS I
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d AND DECISION MAKING FOR BOTH EXISTING AND FUTURE PLANT DESIGNS, INCLUDING MINIMUM CRITERIA 0F ADEQUACY PRAS SHOULD MEET.
THE POLICY STATEMENT ALSO STATED THE COMMISSION'S EXPECTATION THAT "fiEW STAh3ARD (OR CUSTOM) PLANTS, WILL ACHIEVE A HIGHER STAllDARD OF SEVERE ACCIDENT SAFETY PERFORMAf4CE THAtt PRIOR DESIGNS."
7
RELATED INDUSTRY EFFORTS:
ADVANCED LIGHT WATER REACTOR (ALWR) PROGRAM DOE / INDUSTRY ADVANCED REACTOR SEVERE ACCIDENT PROGRAM (ARSAP),
INDUSTRY EXPRESSION OF SUPPORT FOR FUTURE GUIDANCE AT A JUNE 9, 1988 WORKSHOP.
8
BENEFITS OF GUIDANCE "LARIFY COMMISSION REQUIREMENTS AND EXPECTATIONS FOR THE TREATMENT OF SEVERE ACCIDENTS FOR BOTH THE INDUSTRY AND NRC STAFF REVIEWERS, PR0f',0TE STABILITY IN DES.'GN, LICENSitiG AND OPERATION OF NEW PLANTS BY MAKING LICENSING REQUIREMENTS PREDICTABLE.
9
e CODIFY CURRENT STAFF TREATMENT OF SEVERE ACCIDENTS IN ONGOING STANDARD PLAtiT REVIEWS (1.E., ABWR, ETC.)
AVolD HAVING TO LITIGATE SEVERE ACCIDENT REQUIREMENTS AT EACH HEARING (1.E., FACILITATE HEARINGS) AND IN THE LONG RUN SAVE STAFF RESOURCES.
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F ENSURE THAT ENHAtlCED SAFETY IS ACHIEVED THROUGH ELIMINATION OF SIGNIFICANT SEVERE ACCIDENT VULNERABILITIES, INCLUDING THOSE DISCOVERED THRU PAST EXPERIENCE, PRAS AND RESEARCH PROGRAMS.
11
OPTIONS CONSIDERED FOR PROMULGATING GUIDANCE
- 1) UTILIZE GENERAL STATEMENTS PROPOSED tra 10 CFR 52:
REG GUIDES COULD BE DEVELOPED TO PROVIDE ADDITIONAL GUIDANCE ON PRA, SEVERE ACCIDENT ASSESSMEt4TS AND ACCEPTANCE
- CRITERIA,
, 12
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. t AND SEVERE ACCIDENT ASSESSMENT DIRECTED TOWARD IDENTIFYING AND CORRECTING SIGNIFICANT VULNERABILITIES (COVERS SEVERE ACCIDENT PREVENTION AND 1
MITIGATION).
4 REG. GUIDES TO ' ROVIDE ADDITIONAL GUIDAf4CE ON PhA AND SEVERE ACCIDENT ASSESSMENT T
4 COST / BENEFIT ACCEPTANCE CRITERIA.
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- 3) SAME AS OPT 10ti 2 EXCEPT ACCEPTANCE CRITERIA lta REG GUIDES WOULD t10T BE BASED SOLELY ON COST /BE!4EFIT.
(4 ) PRESCRIPTIVE RULE, IllCLUDiriG ACCEPTANCE CRITERIA.
14
c CONCLUSIONS REGARDING OPTIONS OPT 10 tis 2 At4D 4 ARE fl0T BEllEVED TO BE ATTRACTIVE 111 COMPARISON WITH 1 AllD 3.
OPTI0tt 2 - HEAVY REll alice ON COST BEtlEFIT Af.'ALYSIS.
OPTIOrt 4 - PRESCRIPTIVE RULE LIMITS FLEXIBILITY.
15
r OPT 10f1 1 IS BELIEVED TO BE WORKABLE; HOWEVER, IT HAS SOME DISADVANTAGES, NAMELY:
PULE LACKS FOCUS ON IMPORTAf4CE OF SEVERE ACCIDEf;TS Iff FUTURE REACTOR DESIGftS.
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RULE EMPHASIZES PROCEDURAL ASPECTS Af4D NOT PERFORMANCE REQUIREMENTS.
ONLY APPLICABLE TO DESIGNS WHICH UTILIZE 10CFR52, 17
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OPTION 3 PROVIDES ALL THE BENEFITS AND APPEARS TO BE STRONGER IN THAT THE RULE:
MORE SPECIFICALLY ADDRESSES SEVERE ACCIDENT CONCERNS.
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8 O
r APPLICABLE TO STANDARD AND CUSTOM LWR APPLICATIONS.
THEREFORE, STAFF RECOMMENDS THAT OPT!ou 3 BE PURSUED.
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P l
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l SCOPE OF PROPOSED GUIDANCE 4
l PROPOSED RULES AND REGULATORY GUIDES WOULD BE LIMITED To LWR DESIGNS NOT F
I SIGNIFICANTLY DIFFERENT THAN CURRENT GENERATION LWRS (SUcH AS ABWR, APWRS, 4
j AND 600 MWE DESIGNS IN EPRl'S - ALWR i
PROGRAM).
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GUIDANCE FOR LWR DESIGNS SIGNIFICANTLY DIFFERENT THAN CURREfiT GENERATION LWR DESIGNS WOULD BE DEVELOPED LATER IN CONSIDERATION OF THE UNIQUE ATTRIBUTES OF THOSE DESIGils, SO AS NOT TO INHIBIT INNOVAT10f4.
GUIDANCE WILL CollSIST OF A GEf1ERAL F,ULE(S) AllD SUPPORTING REGULATORY GUIDES WHICH:
21
F UPDATE 10CFR50.34(F) TO APPLY TO FUTURE LWRS, INCLUDING A REQUIREMENT FOR A PRA AND TECHNICAL RESOLUTION OF USIS, GSIS AND TMI ITEMS.
REQUIRE SEVERE ACCIDENT VULNERABILITIES BE ASSESSED, INCLUDING SPECIFICALLY ADDRESSING SEVERE ACCIDENT EVENTS / PHENOMENA JUDGED FROM PREVIOUS EXPERIENCE TO BE OF SIGNIFICANT RISK.
72
PROVIDE GUIDANCE Oft ACCEPTANCE CRITERIAJ HOWEVER, DESIGft SOLUT!0flS WILL NOT BE PRESCRIBED.
23
ASSESSMENT OF SEVERE IllTERNAL AtlD EXTERf1AL EVENTS WILL BE REQUIRED.
WILL UTILIZE PRODUCTS OF OTHER ONG0lt4G RELATED PROGRAF 1S AS MUCH AS PRACTICAL, 1
9 0
74
STAFF DOES NOT VIEW THIS EFFORT AS CHANGING THE DEFINITION OF THE ADECUATE LEVEL OF SAFETY FOR REACTORS.
RATHER, IT IS VIEWED AS ENSURING SAFETY ENHAtiCEMENT THRU INCREASED MARGIN FOR SEVERE ACCIDENTS.
25
=
DRAFT RULES AND REG. GUIDES ATTACHED TO THE COMMISS10t1 PAPER ARE ONLY EXAMPLES TO ILLUSTRATE THE SCOPE AND DEPTH OF WHAT IS EtiVISIONED.
FINAL C0t1 TENT AND WORDitiG IS STILL UNDER DEVELOPMEt4T.
l 26 1
ADDITIONAL BENEFITS IN ADDITION TO HAVING FUTURE DESIGNS ASSESSED FOR VULNERABILITIES, SYSTEMATIC ASSESSMENT OF SEVERE ACCIDENTS WILL HELP IDENTIFY AND PRESERVE OTHER ASSUMPTIONS / ACTIONS RELATED TO SAFE OPERATION, SUCH AS:
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PROCEDURES, TRAINING, DESIGN FEATURES FOR ACCIDENT MANAGEMENT MAINTENANCE R&D NEEDS TO REDUCE UNCERTAINTIES EQUIPMENT GUALIFICATION HEEDS i
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SCHEDULE SCHEDULE FOR DEVELOPING GUIDANCE PRESENTLY DRIVEN BY THE SCHEDULE FOR REVIEW OF THE THREE EVOLUTIONARY STAfiDARD REACTOR DESIGNS fiOW UNDER WAY:
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SCHEDULE TASK PROPOSED Rutt fit 4AL RULE WORKSHOP 12/88 11/89 ACRS LTR.
04/89 02/90 To COMM.
05/89 03/90 ISSUE 06/89 05/90 5
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Document Control Desk, 016 Phillips ADVANCED COPY TO:
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FROM:
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