[Federal Register Volume 72, Number 133 (Thursday, July 12, 2007)]
[Proposed Rules]
[Pages 38030-38033]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-13539]


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NUCLEAR REGULATORY COMMISSION

10 CFR Part 50

[Docket No. PRM-50-87]


Raymond A. Crandall; Receipt of Petition for Rulemaking

AGENCY: Nuclear Regulatory Commission.

ACTION: Petition for rulemaking; notice of receipt.

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SUMMARY: The Nuclear Regulatory Commission (NRC) has received and 
requests public comment on a petition for rulemaking dated May 17, 
2007, filed by Raymond A. Crandall (petitioner). The petition was 
docketed by the NRC and has been assigned Docket No. PRM-50-87. The 
petitioner is requesting that the NRC amend the regulations that govern 
domestic licensing of production and utilization facilities to 
eliminate the specific criteria related to the radiological doses for 
control room habitability at nuclear power plants. The petitioner 
believes that the current deterministic radiological dose requirements 
for control room habitability have resulted in several negative safety 
consequences, including an increased risk to public safety.

DATES: Submit comments by September 25, 2007. Comments received after 
this date will be considered if it is practical to do so, but assurance 
of consideration cannot be given except as to comments received on or 
before this date.

ADDRESSES: You may submit comments by any one of the following methods. 
Please include the following number (PRM-50-87) in the subject line of 
your comments. Comments on petitions submitted in writing or in 
electronic form will be made available for public inspection. Because 
your comments will not be edited to remove any identifying or contact 
information, the NRC cautions you against including personal 
information such as social security numbers and birth dates in your 
submission.
    Mail comments to: Secretary, U.S. Nuclear Regulatory Commission, 
Washington, DC 20555. Attention: Rulemaking and Adjudications staff.
    E-mail comments to: [email protected]. If you do not receive a reply e-
mail confirming that we have received your comments, contact us 
directly at (301) 415-1966. You may also submit comments via the NRC's 
rulemaking website at http://ruleforum.llnl.gov. Address comments about 
our rulemaking website to Carol Gallagher, (301) 415-5905; (e-mail 
[email protected]). Comments can also be submitted via the Federal 
eRulemaking Portal http://www.regulations.gov.
    Hand deliver comments to 11555 Rockville Pike, Rockville, Maryland, 
between 7:30 am and 4:15 pm on Federal workdays.
    Publicly available documents related to this petition may be viewed 
electronically on the public computers located at the NRC Public 
Document Room (PDR), O1 F21, One White Flint North, 11555 Rockville 
Pike, Rockville, Maryland. The PDR reproduction contractor will copy 
documents for a fee. Selected documents, including comments, may be 
viewed and downloaded electronically via the NRC rulemaking Web site at 
http://ruleforum.llnl.gov.
    Publicly available documents created or received at the NRC after 
November 1, 1999 are also available electronically at the NRC's 
Electronic Reading Room at http://www.nrc.gov/reading-rm/adams.html. 
From this site, the public can gain entry into the NRC's Agencywide 
Documents Access and Management System (ADAMS), which provides text and 
image files of NRC's public documents. If you do not have access to 
ADAMS or if there are

[[Page 38031]]

problems in accessing the documents located in ADAMS, contact the NRC 
PDR Reference staff at 1-800-397-4209, 301-415-4737 or by e-mail to 
[email protected].
    For a copy of the petition, write to Michael T. Lesar, Chief, 
Rulemaking, Directives and Editing Branch, Division of Administrative 
Services, Office of Administration, U.S. Nuclear Regulatory Commission, 
Washington, DC 20555-0001. The petition is also available 
electronically in ADAMS at ML071490250.

FOR FURTHER INFORMATION CONTACT: Michael T. Lesar, Office of 
Administration, U.S. Nuclear Regulatory Commission, Washington, DC 
20555. Telephone: 301-415-7163 or Toll-Free: 1-800-368-5642 or E-mail: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The NRC has received a petition for rulemaking dated May 17, 2007, 
submitted by Raymond A Crandall (petitioner). The petitioner requests 
that the NRC amend 10 CFR Part 50, ``Domestic Licensing of Production 
and Utilization Facilities.'' Specifically, the petitioner requests 
that 10 CFR 50.67, ``Accident source term'' and ``Criterion 19--Control 
room'' in Appendix A to Part 50, ``General Design Criteria for Nuclear 
Power Plants'' be amended by eliminating the specific criteria related 
to the radiological doses for control room habitability at nuclear 
power plants.
    The NRC has determined that the petition meets the threshold 
sufficiency requirements for a petition for rulemaking under 10 CFR 
2.802. The petition was docketed by the NRC as PRM-50-87 on May 25, 
2007. The NRC is soliciting public comment on the petition for 
rulemaking.

Discussion of the Petition

    The petitioner notes that the current regulations provide specific 
dose criteria, based on deterministic radiological dose analyses 
performed by the licensee and reviewed by the NRC staff for 
demonstrating the acceptability of the control room design for 
radiological release events. NRC regulatory guides and standard review 
plans provide the methodologies used to perform dose analyses that are 
incorporated into a licensee's site-specific technical specifications 
(TS). However, the petitioner believes that the deterministic dose 
analysis methodology and associated regulatory process has resulted in 
several negative safety consequences. The petitioner states that these 
consequences include:
    (1) Control designs that are not optimum for ensuring continued 
control room habitability and may increase the probability of control 
room evacuation.
    (2) Site procedures for mitigation of dose consequences to control 
room personnel that are not optimum for ensuring control room 
habitability and are inconsistent with more effective mitigation 
strategies.
    (3) Unnecessary challenges to safety systems, such as increased 
challenges to the Emergency Diesel Generators if control room 
ventilation system fans are used early in an accident to meet analysis 
assumptions.
    (4) TS action statement requirements that require a plant shutdown 
for failure to meet a control room dose analysis input assumption and 
result in a net increase in the risk to the public.
    (5) TS surveillance requirements that cannot be cost-justified 
based on the risk significance that results in expenditures that could 
be used on risk-significant improvements.
    The petitioner believes the suggested amendments would eliminate 
the specific radiological dose acceptance criteria; the need for 
deterministic dose analyses; and the need for the associated regulatory 
process, including the TS imposed to ensure compliance. The petitioner 
also states that the proposed change does not eliminate the requirement 
for the control room to be designed to ensure safe conditions under 
accident conditions, but would eliminate what he believes are safety 
concerns with the current regulation.
    The petitioner states that because the primary objective of control 
room habitability is to ensure continuous occupancy, the primary focus 
should be on minimization of whole body doses from noble gases. The 
petitioner believes that the current regulation is inconsistent with 
the goal of allowing the control room operator to remain in the control 
room to mitigate accident consequences. He states that some common 
designs focus on compliance with existing criteria, such as a filtered 
air-intake pressurization design, and increase the probability that the 
control room will have to be evacuated. The petitioner has concluded 
that the current requirements and operational criteria are established 
to minimize the thyroid dose at the expense of increasing the whole 
body dose. The petitioner notes that the dose from increased iodine 
concentration can be mitigated by use of potassium iodide (KI) or 
respiratory protection, but that the current requirements do not permit 
these mitigating techniques for radiological releases to be used in 
design analyses. The petitioner believes it is inconsistent that credit 
for respiratory protection is permitted in control room habitability 
toxic gas release evaluations, but not for design analyses.
    The petitioner also states that current procedures for dose 
mitigation are simplified to be consistent with the licensing basis 
hypothetical analysis and that these analyses have resulted in 
procedures that may not be an optimum mitigation strategy for more 
likely conditions. The petitioner believes that mitigation strategies 
should be based on overall risk reduction that would involve strategies 
for more likely conditions. The petitioner has concluded that the 
current mitigation strategies are based on one set of fixed 
hypothetical conditions that are unlikely as a result of the required 
deterministic dose analysis specified in the existing regulation.
    The petitioner states that procedures for dose mitigation must be 
consistent with the licensing basis and may not be the optimum 
mitigation strategy for the more likely conditions. The petitioner 
states that control room dose models do not model dispersion as a 
period during the day with higher concentrations while the plume is 
blowing towards the control room and then a period of zero 
concentration for the rest of the day. Instead, analysis methods 
simplify this effect by assuming that a lower concentration is present 
continuously. The petitioner states that if procedures were revised to 
include a purge mode strategy, a calculated increase in consequences in 
the simplistic design basis analysis would result.
    The petitioner states that the design requirements in the current 
regulations result in unnecessary challenges to safety systems. The 
petitioner cites an example during an assumed loss-of-coolant accident 
(LOCA) and states that a common design requirement specifies that the 
normal control room ventilation must isolate when a safety injection or 
containment isolation signal occurs. The petitioner believes it would 
be more logical to delay control room isolation until radioactivity is 
detected in the control room or it is known that a radioactive plume is 
blowing towards the control room. The petitioner suggests that 
mitigating design strategies should be based on overall risk reduction 
designed for more likely conditions, not on one set of fixed 
hypothetical conditions that the petitioner believes is unlikely.
    The petitioner states that current radiological dose mitigation 
analyses also result in inappropriate TS action

[[Page 38032]]

statements. The petitioner explains that radiological dose analyses 
differ from other types of engineering calculations. The petitioner 
states that even though most engineering analyses involve some amount 
of uncertainty, the results reasonably match what can be expected 
during a real event. The petitioner cites the thermal hydraulic 
analyses for an assumed LOCA event and explains that conservatism is 
built into the model, and that numerous assumptions go into the 
analysis to demonstrate that fuel damage will not occur due to 
overheating. The petitioner states that for other assumptions such as 
the temperature of the safety injection water or the flow rate of the 
safety injection pump, uncertainty is limited by specifying an 
acceptable value for such a parameter in the TS. The petitioner 
believes that TS requirements for a safety injection system that cannot 
meet design requirements impose a shutdown requirement.
    The petitioner states that a large break LOCA is usually the 
limiting accident for control room habitability design and that the 
associated radiological analysis requires multiple inputs, including 
the source term, which is the amount of radioactivity released from the 
reactor core that can reach the environment. The petitioner explains 
that the source term assumption can vary by many orders of magnitude 
and that total curies released is not the only consideration. The 
calculated and actual dose during an event depends on the nuclide mix 
of the release, decay time since reactor shutdown, the fraction of 
particulate nuclides that become airborne, and the chemical form of the 
source term. The petitioner also states that many uncertainties are 
considered in these models that include the removal mechanism for the 
various nuclides; the release pathway and forces that cause a release 
by that pathway; atmospheric dispersion; and dose modeling that depends 
on the size of an exposed individual, their breathing rate, biological 
removal mechanisms, etc.
    The petitioner believes that the combined probability of all 
assumptions being at the high end of uncertainty is so small that the 
design basis event will not be realistic and makes each assumption 
meaningless for predicting actual results. The petitioner cites the 
Three Mile Island accident as an example when the dose analysis input 
assumptions had no significance in predicting the actual consequences 
of the event. The petitioner states that for control room habitability 
TS, the analyses assumptions and results are even further removed from 
any significance because there is no direct public impact from not 
meeting control room habitability system requirements, any dose an 
operator receives can be mitigated by KI, and the dose limit is overly 
restrictive. The petitioner states that the potential indirect impact 
on public safety of having to evacuate the control room can be easily 
avoided, regardless of the control room habitability system status. The 
petitioner has concluded that this means ``there is insignificant 
safety significance to the TS associated with control room habitability 
and yet there are shutdown requirements.''
    The petitioner notes that in the past, the NRC has specified on 
numerous occasions that the inability to meet the assumptions or 
criteria of control room habitability analyses has low safety 
significance. The petitioner states that the primary basis for the low 
safety significance was usually due to the existence of mitigating 
actions such as the issuance of KI tablets to ensure continued 
occupancy of the control room and to justify continued operation. The 
petitioner believes that to evaluate the net public safety risk 
associated with these TS shutdown requirements, small but quantifiable 
public risks associated with the shutdown of a nuclear power plant must 
be considered that include but are not limited to the:
    (1) Risk associated with bringing the plant through a transient and 
another thermal cycle;
    (2) Airborne pollutants released by the fossil units required to 
operate to make up for lost power; and
    (3) Potential for challenging electric power grid stability with 
the public risk associated with the possibility of rolling blackouts or 
brownouts, or under the worst conditions of grid stability, the 
potential for a loss of offsite power at multiple nuclear power 
facilities.
    The petitioner states that the shutdown requirement increases the 
net public risk and has concluded that the shutdown requirement needs 
to be eliminated because it is only imposed as a ``matter of 
compliance'' that he believes results from the way the input 
assumptions are treated when using deterministic calculations.
    The petitioner also states that ``individual input assumptions for 
radiological dose analyses have no significance in predicting reality 
or the acceptability of results. Even if actual conditions were such 
that one of the assumptions was non-conservative by a couple orders of 
magnitude, the ultimate result (in this case habitability of the 
control room) would still be acceptable due to the significant 
conservatisms in the other assumptions and the simplicity of effective 
mitigating actions such as the use of KI.''
    The petitioner states that although most control room habitability 
surveillances can be performed with minimal resources, licensees have 
been required to demonstrate the accuracy of the assumption on 
unfiltered inleakage using a tracer gas testing method that costs 
approximately $100,000 per test and cannot be justified. The petitioner 
believes these tests have demonstrated that although inleakage values 
assumed in the analyses were non-conservative, there was no safety 
significance and continued operation was justified. The petitioner has 
concluded that the expenditure for tracer gas testing could be better 
used for improvements that would likely be more beneficial to plant 
safety and, therefore, the required performance of this test could have 
a net negative safety consequence. The petitioner states that previous 
surveillances, such as a pressurization test, combined with lessons 
learned from tracer gas testing results in an effective preventative 
maintenance program to provide a cost-justified approach to ensure that 
there are no significant failures of the control room habitability 
boundary and an insignificant potential for control room evacuation.

The Petitioner's Proposed Actions

    The petitioner suggests that the regulations should be revised to 
eliminate the specific radiological criteria for control room 
habitability. The petitioner believes this would result in the ability 
to revise the industry guidelines to eliminate the specified guidelines 
for performing deterministic dose analyses and eliminate all negative 
safety consequences discussed in the petition. Specifically, the 
petitioner recommends that 10 CFR 50.67(b)(2)(iii) and the second 
sentence of Criterion 19 of Appendix A to Part 50 that contain specific 
criteria for control room habitability be removed from the regulations.
    The petitioner suggests that the current guidelines be replaced 
with guidelines that he believes would ensure that the control room 
remains habitable under most postulated conditions, such as:
    (1) The control room ventilation system should isolate on the 
detection of high radiation or toxic gas intake.
    (2) The control room should have a minimum of one foot of concrete 
shielding (or equivalent) on all surfaces.
    (3) Self Contained Breathing Apparatus (SCBAs) and KI tablets 
should be readily available for operator

[[Page 38033]]

use. Operators should maintain training in SCBAs.
    (4) Procedural controls to maintain a low leakage boundary, such as 
preventive maintenance/routine inspection of door seals and dampers 
should be implemented.
    (5) Procedures should be developed to ensure control room purging 
is considered when the outside concentration is less than the inside 
concentration.
    (6) Existing emergency filtration systems should be maintained to 
practical performance criteria.
    The petitioner also states that current TS for system performance 
would be eliminated and that the administrative portion of the TS could 
include a requirement to have a Control Room Habitability Program. The 
petitioner believes that because of the low public risk significance of 
being outside design guidelines in a Control Room Habitability Program, 
a plant shutdown would not be required if it is outside of the 
guidelines. Rather, the petitioner believes that the program could 
specify that timely actions should be taken to return the plant within 
the guidelines. If not complete within 30 days, the petitioner suggests 
that a special report would be sent to the NRC with a justification for 
continued operation and a proposed schedule for meeting the guidelines.
    The petitioner states that removing the specific dose criteria 
would not eliminate the need to perform quantitative analyses as 
required to demonstrate the acceptability for certain conditions. The 
petitioner also states that although the current regulation has no 
specific quantitative limits for toxic gases, the guidelines require 
quantitative analyses for toxic gas habitability assessments under 
certain conditions. The petitioner suggests that as an alternative to 
total removal of dose guidelines from the regulations, most of his 
concerns could be resolved if the dose criteria were based solely on 
the whole body dose from noble gases that he believes is the only 
possible dose impact that may result in control room evacuation. The 
petitioner suggests, as another option, that most of his concerns would 
be resolved if credit for SCBAs and/or KI was allowed in the analysis 
of the dose from iodine and particulates. The petitioner also proposes 
that the TS be revised to eliminate shutdown requirements for failure 
to meet control room habitability requirements.

    Dated at Rockville, Maryland, this 6th day of July 2007.

    For the Nuclear Regulatory Commission.
J. Samuel Walker,
Acting Secretary of the Commission.
[FR Doc. E7-13539 Filed 7-11-07; 8:45 am]
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