ML20034D465
| ML20034D465 | |
| Person / Time | |
|---|---|
| Issue date: | 09/04/1992 |
| From: | Federline M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Ballard R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-1 NUDOCS 9209110087 | |
| Download: ML20034D465 (8) | |
Text
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$EP 4 1991 i
MEMORANDUM FOR:
Ronald L.
Ballard, Chief Geology and Engineering Branch Division of High-Level Waste Management t
FROM:
Margaret V.
Federline, Chief Hydrology and Systems Performance Branch Division of High-Level Waste Management
SUBJECT:
REVIEW OF PROPOSED DBE RULE AND COMPANION SECY PAPER DATED AUGUST 27, 1992 The Performance Assessment staff has reviewed the subject documents and has the following general comments.
In addition, four pages of marked-up text are also enclosed with this memo.
Comment 1:
Proposed Change to Section 60.21(c) (3), see page 17.
Although the proposed revision to 60.21(c) (3) would require compliance with 10 CFR Part 20, it does not address compliance with environmental regulations of the EPA (as required by Section 60.111(a) in 10 CFR Part 60).
I suggest, for completeness, that the language for Section 60.21(c) (3) on page 17 be changed to refer to Section 60.111(a) of 10 CFR Part 60 rather than to the requirements of 10 CFR 20.
It should be recognized that this requirement may be more stringent than the EPA intended for its environmental regulations.
Comment 2:
Consistency in use of language, see page 17.
)
The proposed language in the " Content of Application," (Section i
- 60. 21 (c) (3 ), sentence 1, section i) contains the words " reasonably likely," and the proposed language in the definition of design basis events (Section 60.2, page 16) contains the phrase
" reasonably be expected."
I suggest that the same language be used in both sections of the proposed rule.
Comment 3:
Proposed Change to the discussion in the Supplementary Information for Section 60.21, see page 12.
For clarity, include the following concepts into the discussion in Section 60.21 of the Supplementary Information.
For both the underground and surface facilities, the proposed amendment to i
Section 60.21(c) (3) would require the licensee to comply with both the dose limits in 10 CFR Part 20 (100 mrems/ year for the public and 5 rems / year for workers), and such generally applicable environmental standards as may have been published by the EPA, assuming occurrence of events that are reasonably likely prior to Y
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2 permanent closure (Design Events 1 through 3).
In addition, the licensee would also be required to comply with the reference doses in Section 60.123 (e.g., 5 rems per accident to any individual) for all design basis events (Design Events 1 through 4).
Comment 4:
Comparative Risk This section of the Commission Paper (dated 8/27/92), which pertains to the calculation of risk, generally reflects the positions taken in the past by HLHP for this rulemaking.
However, for clarity, I propose that you substitute the language in attachment 1 to this memo to the Comparative Risk section of the Paper.
Comment 5:
Units for Dose The doses in rems should be followed by their equivalents in Sieverts in both subject documents.
Comment 6:
New paragraph (11) for 60.131(b)
The proposed new paragraph would require prevention or mitigation of damage to HLW or HLW containers for all design basis events.
Interpretation of the term " prevent or mitigate" could range from virtually complete assurance of prevention of damage to the merest hint of mitigation of the consequencer of dauage.-
Moreover, the explanation of this new criterion en page 14 suggests that it is meant to provide a substantial degree of protection to workers even following the occurrence of unlikely category IV design basis events.
We had understood that this degree of worker protection was not to be required for such rare events.
Since the meaning of this term is so unclear, and since the proposed new criterion neems to be inconsistent with the Commission's other regulations for occupational safety, we recommend that paragraph (11) not be proposed for addition to 60.131(b).
Instead, paragraph (1) should be reworded as follows:
(1)
Protection aaainst natural phenomen; and envircn=cntal conditienc desian basis events.
The structures, systems and components important to safety shall be designed so that they will perform their necessary safety functions assuming occurrence of design basis events attributable to the Occurrence of natural phenc=cna cr resulting frcm envircn= ental conditienc in the cite.
On page 14, the text of the first paragraph should also be deleted, from "However, in order to.
" through the end of the paragraph.
ENCLOSURE 1 COMPARATIVE RISK The amendments proposed here would allow a person located at the boundary of the controlled-use area to receive a maximum accident radiation dose of 5 rems.
This dose limit would be allowed only for those accidents that are unlikely to occur during the 100 year operating lifetime of a repository -- that is, those accidents with frequencies on the order of 10~8/ year or less.
The fatal cancer risk for such accidents would be given by the following expression:
Risk = (10-8/yr) (5 rem) (5 X 10-' risk / rem)
- 2. 5 X 10-'/ year
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For comparison, the revisions to 10 CFR Part 20 allow non-occupational doses to be as large as 0.1 ren/ year.
The fatal cancer risk associated with such doses would be:
Risk = (0.1 ren/yr) (5 X 10~' risk /ren)
= 5 X 10-5/yr Thus, the amendments proposed here would impose a risk to members of the public that is only a small fraction of the level of risk currently permitted by Part 20.
(The number, 5 X 10-' risk / rem, is taken from the supplementary information for the revised 10 CFR 20, 56 FR 23363.)
yy ENCLOSURE 2 The Federal Reaister also noted that the DOE s
approach differed markedly from that contemplated T
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gf by NRC.
The DOE proposed rule would continue to 9'
MMN identify structures,
- systems, and components k
i important to
- safety, relative to a
reference boundary dose.
It would be possible to extend'the y >. >
boundary of the controlled area such the potential (g gi dose would be reduced through dilution and no structures,
- systems, or components would be p(, g identified as important to safety.
As a result, ki certain safety and quality assurance requirements (y linked to these important-to-safety items would ka 29l
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Although jpdP public protection might be D
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adequate, the safety of workers would -';
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Q k j; NRC envisioned that the scope of, and the design criteria for, structures, systems, and components important to safety would be derived from d
k consideration of the functional requirements of the g*f )
i repository system.
Accordingly, safety and quality assurance requirements for structures, systems, and component items would be retained and worker
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Only DOE commented on the Federal Recister notice k(
(Enclosure 4).
In its comments, DOE stated the j
intent to irlplement NRC guidance on quality L
I' assurance and to meet the requirements of Part 20 i
that would ensure worker safety through M
implementation of NUREG-1318, and urged proceeding
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with the petition for rulemaking.
The staff chose Y {h to proceed with its regulatory initiative and informed DOE of the petition status in July 1991.
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'O Discussion:
The intent of the proposed rule change is to l
correct deficiencies in Part 60 related to worker g 4 l and public protection and inconsistencies with n
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agency rules that regulate similar types of
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facilities.
This is accomplished as discussed next.
The definition of "important to safety" is changed to a functional definition, as in Part 72, rather than the present dose-related definition.
Structures, systems, and components will now be "important to safety" and subject to quality assurance and special design requirements, if they are important to: store HLW safely; prevent or mitigate damage to HLW or HLW containers; or provide reasonable assurance that HLW can be received, handled, and retrieved without undue risk to the health and safety of the public.
In this definition, structures,
- systems, and l
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i design basis for other regulated facilities, including nuclear L
reactors.
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<6 Section 60.21.
Content of application.
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The petition for rulemaking suggested that provision for accident, p analysis might be accomplished by amendment of 10 CFR 60.111.
The d
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commission proposes instead to provide for an accident analysis as Gy'f part of the content of application section (i.e.,
10 CFR 60. 21).
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The proposed language would require the application to address the Ji g potential dose, to an individual on or beyond the controlled-use i
area boundary, that is attributable to the full range of design 9>
is that the E
I basis events.
The procedure that is envisaged applicant would address the critical design basis events c ? h k '
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ese, and demonstrate by its analysis that the doses on or beyond
,2 the controlled-use area boundary would be in accordance with the J
h applicable standards.
The proposed language serves the same purpose as the counterpart section of Part 72 (namely 10 CFR it 72.24 (m) ).
O The proposed rule would also reflect the position, outlined
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above, that the applicant should demonstrate compliance with Part g
i 20 assuming the occurrence of any events that are reasonably likely j
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to occur " prior to permanent closure" (a phrase that is used 1
2 inte: changeably with "until permanent closure has been completed").
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The Commission also proposes to eliminate certain terms t
pertaining to the functions of structures, systems, and components t
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important to safety that may be subject to differing 'g intarpretations -- specifically,. the tcrxs " normal conditions,"
" anticipated operational occurrences," non " accidents."
Besides pI enhancing clarity of expr.ession, the nw e mguage better reflects l
the policy framework articulated above.
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section 60.12.3.
Controlled-use area.
k The proposed rule would adopt the petitioner's concept of a L
preclosure control area, but under the name " controlled-use area" o
instead.
The function of this area, it should be recalled, is to
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define a zone from which members of the public can be excluded under the unusual conditions that have here been characterized as Design Event IV credible yet not likely to occur during the period of operations.
The issue that is presented concerns the y
reference dose on or beyond the controlled-use area boundary that M
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is appropriate to assure that the occurrence of any such events i
presents no unreasonable risk to the health and safety of the public.
(Releases resulting from events classified' as Design Events I,
II, and III would not be permitted to cause doses exceeding the limits of Part 20.)
The Commission proposes to adapt the basic provisions of Part 72 - namely, a reference 5-rem dose on
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4 or be end the cont olled-use area boundary - as modified to reflect K('
the re ntly amended Part 20.
4 ':_ v Qq To a complish this, there would be th-r eference doses: a 4
total effe tive p se equivalent of 5 rems d n eye dose equivalent D
of 15 rems; and reference crgar dere, fer 2ny Other Organ, Of 50 v
peam The htt' "" reference doses are adequate to ensure that h ;
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no observable effects (e.g., induction of cataracts in the 1 ens of y
the eye) will a result of any accidental radiation g ge g as Thepare, reference dose, which restricts the total exposure.
effective dose equivalent, addresses the fatal cancer risk.
A 5-rems total effective dose equivalent, when applied to the low-
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probability conditions of Design Event IV (those credible events j
l but unlikely to occur during the operating life of the facility),
g would ensure that the fatal cancer risk from Design Event IV V 5
I releases would be only a small fraction of the risk permitted by tha N.issicr' regulations for routine facility operations. jk!
3 r"~~Tiius, the total risk experienced by members of the public, t
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including the risk due to accidental releases, would not be e
d significantly greater than the risk associated with the %
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Commission's Part 20 routine release limit of 0.1 rem per year.
L Considering the low probability of occurence of any Design Basis $
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Event IV, the Commission views these limits as providing an adequate level of protection.
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f The only other noteworthy deviation from Part 72 (specifically g Section 72.106) would be to refer to doses attributable to any g
" design basis event" instead of any " design basis accident." The,i 9
l term " design basis accident" is avoided because it lacks a
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definition.
A design basis accident is merely the consequence of g
some design basis event, and so the change in terminology is not N 5 U
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intended to be one of substance.
5 f'C Section 60.131.
General design criteria for the geologic o
g repository operations area.
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This section is important in accomplishing the Commission's a
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defense-in-depth objectives.
The way this is achieved is by \\t requiring that certain structures, systems, and components must be f{
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able to achieve prescribed performance levels under a defined range of conditions.
The rule currently employs the term " normal and j4 accident conditions", or similar expression, in several places. 4 t
However, the conditions that must be addressed under this language
- 3 is poorly defined.
The Commission proposes to remedy this (O situation by replacing current terminology with references to o
" design basis events,"
thereby assuring that the design Y
appropriately takes into account the consequences of all design fa basis events (i.e., as discussed in this document, Design Events I,
)
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s II,
- III, and IV).
Accordingly, modification of paragraphs (b) (5) (i), (b) (7), and (b) (8) is being propcsed.
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(b) Structures, systems, and components Itmoortant to safety --
(1)
Protection acainst m + u r a l r % S G tri o 4 U Ot SM hencren: cnd wvu vu..en;41
-ec r d i t i o n s.
The structures, systems and components important to safety shall be designed so that they will perform their necessary safety functions assuming occurrence of design basis events.
l attributable te the Occurrence cf natural phenomen2 cr reculting fivu encircracntcl Ocnditivus in the site.
J (5) Utility services.
(i) Each utility service system that is important to safety shall be designed so that essential safety functions can be performed assuming occurrence of the design basis events should occur.
1 (7)
Criticality control.
All systems for processing, transporting,
- handling, storage, retrieval, emplacement, and isolation of radioactive waste shall be designed to ensure that a nuclear criticality accident is not possible unless at least two unlikely, independent, and concurrent or sequential changes have occurred in the conditions essential to nuclear criticality safety.
a' Each system shall be designed for criticality safety assuming occurrence of design basis events.
The calculated effective multiplication factor (keff) must be sufficiently below unity to show at least a 5% margin, after allowance for the bias in the method of calculation and the uncertainty in the experiments used to validate the method of calculation.
(8) Instrumentation and control svstems.
The design shall include provisions for instrumentation and control systems to monitor and control the behavior of systems important to safety assuming occurrence of design basis events.
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(11) The s ru tures, systems, nd component important to i
safety shall be e igne o as to p e' nt or m' gate damage to d
- HLW, or high A
radioactive
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- tainers, assuming]
occurrence design basis eve v---
6.
In 10 CFR 60.132, paragraph (c) is modified to read as follows:
J Sec+. ion 60.132 Additional design criteria for surface f acilities in g
the geologic repository operations area.
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This language would accomplish much the same goal as the proposed l
new paragraph (11) (requiring consideration of all design basis l
events for things important to safety), but would avoid the ambiguities in the " prevent or mitigate" term.
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/s/ MV Federline l
Margaret V.
Federline, Chief Hydrology and Systems Performance Branch Division of High-Level Waste Management
Enclosures:
1.
Comparative Risk 2.
4 Marked-up pages i
DISTRIBUTION:
CNWRA-920146 Central File BJYoungblood, HLWM JJLinehan, HLWM HLHP r/f MVFederline, HLHP RLBallard, HLEN JHolonich, HLPD NMSS r/f DFehringer, HLHP RNeel, HLHP MNataraja, HLEN DChery PAltomare, HLPD BJagannath, HLEN JWolf, OGC 38-I b
LSS F
YF p
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n HLHP h\\ f/))[ l
- b. I @
l HLHP HLHP
_ f HLHP OFC v.w-NAME Fehringer/g RNeelpty DChery)lhgsy MVFederline v-
- jy y
V DATE 09/
/92 09/
/92 09/./92 09/4-/92 OFFICIAL RECORD COPY
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