The Attorney General of Commonwealth of Massachusetts, The Attorney General of California; Denial of Petitions for Rulemaking, 46204-46213 [E8-18291]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 73, Number 154 (Friday, August 8, 2008)]
[Proposed Rules]
[Pages 46204-46213]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-18291]


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Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

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Federal Register / Vol. 73, No. 154 / Friday, August 8, 2008 / 
Proposed Rules

[[Page 46204]]



NUCLEAR REGULATORY COMMISSION

10 CFR Part 51

[Docket No. PRM-51-10, NRC-2006-0022 and Docket No. PRM-51-12, NRC-
2007-0019]


The Attorney General of Commonwealth of Massachusetts, The 
Attorney General of California; Denial of Petitions for Rulemaking

AGENCY: Nuclear Regulatory Commission (NRC).

ACTION: Petition for rulemaking; denial.

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SUMMARY: The NRC is denying two petitions for rulemaking (PRM), one 
filed by the Attorney General of the Commonwealth of Massachusetts 
(Massachusetts AG) and the other filed by the Attorney General for the 
State of California (California AG), presenting nearly identical issues 
and requests for rulemaking concerning the environmental impacts of the 
high-density storage of spent nuclear fuel in large water pools, known 
as spent fuel pools (SFPs). The Petitioners asserted that ``new and 
significant information'' shows that the NRC incorrectly characterized 
the environmental impacts of high-density spent fuel storage as 
``insignificant'' in its National Environmental Policy Act (NEPA) 
generic environmental impact statement (EIS) for the renewal of nuclear 
power plant licenses. Specifically, the Petitioners asserted that spent 
fuel stored in high-density SFPs is more vulnerable to a zirconium fire 
than the NRC concluded in its NEPA analysis.

ADDRESSES: You can access publicly available documents related to these 
petitions for rulemaking using the following methods:
    Federal e-Rulemaking Portal: Go to https://www.regulations.gov and 
search for documents filed under Docket ID [NRC-2006-0022] (PRM-51-10), 
and [NRC-2007-0019] (PRM-51-12).
    NRC's Public Document Room (PDR): The public may examine and have 
copied for a fee publicly available documents at the NRC's PDR, Public 
File Area O1 F21, One White Flint North, 11555 Rockville Pike, 
Rockville, Maryland.
    NRC's Agencywide Documents Access and Management System (ADAMS): 
Publicly available documents created or received at the NRC are 
available electronically at the NRC's electronic Reading Room at http:/
/www.nrc.gov/reading-rm/adams.html. From this page, the public can gain 
entry into ADAMS, which provides text and image files of NRC's public 
documents. If you do not have access to ADAMS or if there are problems 
in accessing the documents located in ADAMS, contact the NRC PDR 
reference staff at 1-899-397-4209, 301-415-4737, or by e-mail to 
pdr.resource@nrc.gov.

FOR FURTHER INFORMATION CONTACT: L. Mark Padovan, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001, telephone (301) 415-1423, e-mail Mark.Padovan@nrc.gov.

SUPPLEMENTARY INFORMATION: 

I. Background
II. Petitioners' Requests
III. Public Comments
IV. NEPA and NUREG-1437
V. Reasons for Denial--General
    A. Spent Fuel Pools
    B. Physical Security
    C. Very Low Risk
VI. Reasons for Denial--NRC Responses to Petitioners' Assertions
    A. New and Significant Information
    B. Spent Fuel Assemblies Will Burn if Uncovered
    1. Heat Transfer Mechanisms
    2. Partial Drain-Down
    3. License Amendments
    C. Fuel Will Burn Regardless of its Age
    D. SFP Zirconium Fire Will Propagate
    E. SFP Zirconium Fire May Be Catastrophic
    1. Not New and Significant Information; Very Low Probability
    2. Shearon Harris Atomic Safety and Licensing Board Panel 
(ASLBP) Proceeding
    3. SFP Zirconium Fire Does Not Qualify As a DBA
    F. Intentional Attack on a SFP is ``Reasonably Foreseeable''
    1. NAS Report
    2. Ninth Circuit Decision
    G. SFP Zirconium Fire Should be Considered within the Analysis 
of SAMAs
VII. Denial of Petitions

I. Background

    The NRC received two PRMs requesting that Title 10 of the Code of 
Federal Regulations (10 CFR), Part 51, be amended. The Massachusetts AG 
filed its petition on August 25, 2006 (docketed by the NRC as PRM-51-
10). The NRC published a notice of receipt and request for public 
comment in the Federal Register on November 1, 2006 (71 FR 64169). The 
California AG filed its petition on March 16, 2007 (docketed by the NRC 
as PRM-51-12). PRM-51-12 incorporates by reference the facts and legal 
arguments set forth in PRM-51-10. The NRC published a notice of receipt 
and request for public comment on PRM-51-12 in the Federal Register on 
May 14, 2007 (72 FR 27068). The California AG filed an amended petition 
(treated by the NRC as a supplement to PRM 51-12) on September 19, 
2007, to clarify its rulemaking request. The NRC published a notice of 
receipt for the supplemental petition in the Federal Register on 
November 14, 2007 (72 FR 64003). Because of the similarities of PRM-51-
10 and PRM-51-12, the NRC evaluated the two petitions together.
    The Petitioners asserted the following in their petitions:
    1. ``New and significant information'' shows that the NRC 
incorrectly characterized the environmental impacts of high-density 
spent fuel storage as ``insignificant'' in the NRC's NUREG-1437, 
Generic Environmental Impact Statement for License Renewal of Nuclear 
Plants, May 1996. Specifically, the Petitioners asserted that an 
accident or a malicious act, such as a terrorist attack, could result 
in an SFP being drained, either partially or completely, of its cooling 
water. The Petitioners further asserted that this drainage would then 
cause the stored spent fuel assemblies to heat up and then ignite, with 
the resulting zirconium fire releasing a substantial amount of 
radioactive material into the environment.
    2. The bases of the ``new and significant information'' are the 
following:
    a. NUREG-1738, Technical Study of the Spent Fuel Pool Accident Risk 
at Decommissioning Nuclear Power Plants, January 2001
    b. National Academy of Sciences Committee on the Safety and 
Security of Commercial Spent Nuclear Fuel Storage, Safety and Security 
of Commercial

[[Page 46205]]

Spent Nuclear Fuel Storage (National Academies Press: 2006) (NAS 
Report)
    c. Gordon R. Thompson, ``Risks and Risk-Reducing Options Associated 
with Pool Storage of Spent Nuclear Fuel at the Pilgrim and Vermont 
Yankee Nuclear Power Plants,'' May 25, 2006 (Thompson Report)
    3. Specifically, the Petitioners asserted that the ``new and 
significant'' information shows the following:
    a. The fuel will burn if the water level in an SFP drops to the 
point where the tops of the fuel assemblies are uncovered (complete or 
partial water loss resulting from SFP drainage being caused by either 
an accident or terrorist attack).
    b. The fuel will burn regardless of its age.
    c. The zirconium fire will propagate to other assemblies in the 
pool.
    d. The zirconium fire may be catastrophic.
    e. A severe accident caused by an intentional attack on a nuclear 
power plant SFP is ``reasonably foreseeable.''
    The Petitioners also asserted that new and significant information 
shows that the radiological risk of a zirconium fire in a high-density 
SFP at an operating nuclear power plant can be comparable to, or 
greater than, the risk of a core-degradation event of non-malicious 
origin (i.e., a ``severe accident'') at the plant's reactor. 
Consequently, the Petitioners asserted that SFP fires must be 
considered within the body of severe accident mitigation alternatives 
(SAMAs).

II. Petitioners' Requests

    PRM-51-10 requested that the NRC take the following actions:
    1. Consider new and significant information showing that the NRC's 
characterization of the environmental impacts of spent fuel storage as 
insignificant in NUREG-1437 is incorrect.
    2. Revoke the regulations which codify that incorrect conclusion 
and excuse consideration of spent fuel storage impacts in NEPA 
decision-making documents, namely, 10 CFR 51.53(c)(2), 51.95(c) and 
Table B-1, ``Summary of Findings on NEPA Issues for License Renewal of 
Nuclear Power Plants,'' of appendix B to subpart A of 10 CFR Part 51. 
Further, revoke 10 CFR 51.23(a) and (b), 51.30(b), 51.53, 51.61, and 
51.80(b) to the extent that these regulations find, imply, or assume 
that environmental impacts of high-density pool storage are 
insignificant, and therefore need not be considered in any plant-
specific NEPA analysis.
    3. Issue a generic determination that the environmental impacts of 
high-density pool storage of spent fuel are significant.
    4. Require that any NRC licensing decision that approves high-
density pool storage of spent fuel at a nuclear power plant, or any 
other facility, must be accompanied by a plant-specific EIS that 
addresses the environmental impacts of high-density pool storage of 
spent fuel at that nuclear plant and a reasonable array of alternatives 
for avoiding or mitigating those impacts.
    5. Amend its regulations to require that SAMAs that must be 
discussed in utility company environmental reports (ERs) and NRC 
supplemental EISs for individual plants under 10 CFR 51.53(c)(3)(ii)(L) 
and Table B-1 of appendix B to subpart A of 10 CFR part 51 
(``Postulated Accidents: Severe Accidents'') must include alternatives 
to avoid, or mitigate, the impacts of high-density pool zirconium 
fires.
    PRM-51-12 incorporates by reference PRM-51-10. PRM-51-12 requested 
that the NRC take the following actions:
    1. Rescind all NRC regulations found in 10 CFR part 51 that imply, 
find, or determine that the potential environmental effects of high-
density pool storage of spent nuclear fuel are not significant for 
purposes of NEPA and NEPA analysis.
    2. Adopt, and issue, a generic determination that approval of such 
storage at a nuclear power plant, or any other facility, does 
constitute a major federal action that may have a significant effect on 
the human environment.
    3. Require that no NRC licensing decision that approves high-
density pool storage of spent nuclear fuel at a nuclear power plant, or 
other storage facility, may issue without the prior adoption and 
certification of an EIS that complies with NEPA in all respects, 
including full identification, analysis, and disclosure of the 
potential environmental effects of such storage, including the 
potential for accidental or deliberately caused release of radioactive 
products to the environment, whether by accident or through acts of 
terrorism, as well as full and adequate discussion of potential 
mitigation for such effects, and full discussion of an adequate array 
of alternatives to the proposed storage project.

III. Public Comments

    The NRC's notice of receipt and request for public comment invited 
interested persons to submit comments. The comment period for PRM 51-10 
originally closed on January 16, 2007, but was extended through March 
19, 2007. The public comment period for PRM 51-12 closed on July 30, 
2007. Accordingly, the NRC considered comments received on both 
petitions through the end of July 2007. The NRC received 1,676 public 
comments, with 1,602 of these being nearly identical form e-mail 
comments supporting the petitions. Sixty-nine other comments also 
support the petitions. These comments were submitted by States, private 
organizations, and members of the U.S. Congress. Two letters from the 
Nuclear Energy Institute (NEI) oppose the petitions, and three nuclear 
industry comments endorse NEI's comments.
    In general, the comments supporting the petitions focused on the 
following main elements of the petitions:
     NRC should evaluate the environmental impacts (large 
radioactive releases and contamination of vast areas) of severe 
accidents and intentional attacks on high-density SFP storage in its 
licensing decisions (NEPA analysis).
     The 2006 decision of the United States Court of Appeals 
for the Ninth Circuit, San Luis Obispo Mothers for Peace v. NRC, 449 
F.3d 1016 (9th Cir. 2006), cert. denied 127 S. Ct. 1124 (2007), 
concluded that the NRC must evaluate the environmental impacts of a 
terrorist attack on SFP storage in its licensing decisions.
     NRC's claim that the likelihood of a SFP zirconium fire is 
remote is incorrect. Partial loss of water in an SFP could lead to a 
zirconium fire and release radioactivity to the environment.
     NRC's characterization of the environmental impacts of 
high-density SFP storage as ``insignificant'' in NUREG-1437 is 
incorrect, and the NRC should revoke the regulations which codify this.
     Any licensing decision approving high-density spent fuel 
storage should have an EIS.
    Comments opposing the petitions centered on the following:
     Petitioners failed to show that regulatory relief is 
needed to address ``new and significant'' information concerning the 
potential for spent fuel zirconium fires in connection with high-
density SFP storage. None of the documents that the Petitioners cited 
or referenced satisfy the NRC's standard for new and significant 
information.
     Petitioners failed to show that the Commission should 
rescind its Waste Confidence decision codified at 10 CFR 51.23, or 
change its determination that the environmental impacts of high-density 
spent fuel storage are insignificant.
     The Commission has recently affirmed its longstanding view 
that NEPA demands no terrorism inquiry,

[[Page 46206]]

and that the NRC therefore need not consider the environmental 
consequences of hypothetical terrorist attacks on NRC-licensed 
facilities.
     The Commission's rejection of the Ninth Circuit Court's 
view is consistent with the U.S. Supreme Court's position that NEPA 
should not be read to force agencies to consider environmental impacts 
for which they cannot reasonably be held responsible. Moreover, the NRC 
has, in fact, examined terrorism under NEPA and found the impacts 
similar to the impacts of already-analyzed, severe reactor accidents.
    The NRC reviewed and considered the comments in its decision to 
deny both petitions, as discussed in the following sections:

IV. NEPA and NUREG-1437

    The NRC's environmental protection regulations in 10 CFR Part 51 
identify renewal of a nuclear power plant operating license as a major 
federal action significantly affecting the quality of the human 
environment. As such, an EIS is required for a plant license renewal 
review in accordance with the NEPA. The Petitioners challenge NUREG-
1437, which generically assesses the significance of various 
environmental impacts associated with the renewal of nuclear power 
plant licenses. NUREG-1437 summarizes the findings of a systematic 
inquiry into the potential environmental consequences of operating 
individual nuclear power plants for an additional 20 years. The 
findings of NUREG-1437 are codified in Table B-1 of appendix B to 
subpart A of 10 CFR part 51.
    The NUREG-1437 analysis identifies the attributes of the nuclear 
power plants, such as major features and plant systems, and the ways in 
which the plants can affect the environment. The analysis also 
identifies the possible refurbishment activities and modifications to 
maintenance and operating procedures that might be undertaken given the 
requirements of the safety review as provided for in the NRC's nuclear 
power plant license renewal regulations at 10 CFR part 54.
    NUREG-1437 assigns one of three impact levels (small, moderate, or 
large) to a given environmental resource (e.g., air, water, or soil). A 
small impact means that the environmental effects are not detectable, 
or are so minor that they will neither destabilize, nor noticeably 
alter, any important attribute of the resource. A moderate impact means 
that the environmental effects are sufficient to alter noticeably, but 
not to destabilize, important attributes of the resource. A large 
impact means that the environmental effects are clearly noticeable, and 
are sufficient to destabilize important attributes of the resource.
    In addition to determining the significance of environmental 
impacts associated with license renewal, the NRC determined whether the 
analysis in NUREG-1437 for a given resource can be applied to all 
plants. Under the NUREG-1437 analysis, impacts will be considered 
Category 1 or Category 2. A Category 1 determination means that the 
environmental impacts associated with that resource are generic (i.e., 
the same) for all plants. A Category 2 determination means that the 
environmental impacts associated with that resource cannot be 
generically assessed, and must be assessed on a plant-specific basis.
    The NRC regulations at 10 CFR part 51, subpart A, appendix B, Table 
B-1 and NUREG-1437 set forth three criteria for an issue to be 
classified as Category 1. The first criterion is that the environmental 
impacts associated with that resource have been determined to apply to 
all plants. The second criterion is that a single significance level 
(i.e., small, moderate, or large) has been assigned to the impacts.\1\ 
The third criterion is that the mitigation of any adverse impacts 
associated with the resource has been considered in NUREG-1437 and 
further, it has been determined that additional plant-specific 
mitigation measures are not likely to be sufficiently beneficial to 
warrant implementation. For Category 1 issues, the generic analysis may 
be adopted in each plant-specific license renewal review.
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    \1\ A note to Table B-1 states that significance levels have not 
been assigned ``for collective off site radiological impacts from 
the fuel cycle and from high level waste and spent fuel disposal.'' 
10 CFR part 51, subpart A, app. B, Table B-1, n. 2.
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    A Category 2 classification means that the NUREG-1437 analysis does 
not meet the criteria of Category 1. Thus, on that particular 
environmental issue, additional plant-specific review is required and 
must be analyzed by the license renewal applicant in its ER.
    For each license renewal application, the NRC will prepare a draft 
supplemental EIS (SEIS) to analyze those plant-specific (Category 2) 
issues. Neither the SEIS nor the ER is required to cover Category 1 
issues. However, both are required to consider any new and significant 
information for Category 1 or unidentified issues. The draft SEIS is 
made available for public comment. After considering public comments, 
the NRC will prepare and issue the final SEIS in accordance with 10 CFR 
51.91 and 51.93. The final SEIS and NUREG-1437, together, serve as the 
requisite NEPA analysis for any given license renewal application.
    The NUREG-1437 analysis, as shown in Table B-1 of appendix B to 
subpart A of 10 CFR part 51, found that the environmental impact of the 
storage of spent nuclear fuel, including high-density storage, in SFPs, 
during any plant refurbishment or plant operation through the license 
renewal term, are of a small significance level and meet all Category 1 
criteria. It is this finding that the Petitioners challenge. After 
reviewing the petitions and the public comments received, the NRC has 
determined that its findings in NUREG-1437 and in Table B-1 remain 
valid, both for SFP accidents and for potential terrorist attacks that 
could result in an SFP zirconium fire.

V. Reasons for Denial--General

A. Spent Fuel Pools

    Spent nuclear fuel offloaded from a reactor is stored in a SFP. The 
SFPs at all nuclear plants in the United States are massive, extremely-
robust structures designed to safely contain the spent fuel discharged 
from a nuclear reactor under a variety of normal, off-normal, and 
hypothetical accident conditions (e.g., loss of electrical power, 
floods, earthquakes, or tornadoes). SFPs are made of thick, reinforced, 
concrete walls and floors lined with welded, stainless-steel plates to 
form a leak-tight barrier. Racks fitted in the SFPs store the fuel 
assemblies in a controlled configuration (i.e., so that the fuel is 
both sub-critical and in a coolable geometry). Redundant monitoring, 
cooling, and makeup-water systems are provided. The spent fuel 
assemblies are positioned in racks at the bottom of the pool, and are 
typically covered by at least 25 feet of water. SFPs are essentially 
passive systems.
    The water in the SFPs provides radiation shielding and spent fuel 
assembly cooling. It also captures radionuclides in case of fuel rod 
leaks. The water in the pool is circulated through heat exchangers for 
cooling. Filters capture any radionuclides and other contaminants that 
get into the water. Makeup water can also be added to the pool to 
replace water loss.
    SFPs are located at reactor sites, typically within the fuel-
handling (pressurized-water reactor) or reactor building (boiling-water 
reactor). From a structural point of view, nuclear power plants are 
designed to protect against external events such as tornadoes, 
hurricanes, fires, and floods. These structural features, complemented 
by the deployment of effective and visible

[[Page 46207]]

physical security protection measures, are also deterrents to terrorist 
activities. Additionally, the emergency procedures and SAMA guidelines 
developed for reactor accidents provide a means for mitigating the 
potential consequences of terrorist attacks.

B. Physical Security

    The Petitioners raise the possibility of a successful terrorist 
attack as increasing the probability of an SFP zirconium fire. As the 
NAS Report found, the probability of terrorist attacks on SFPs cannot 
be reliably assessed, quantitatively or comparatively. The NRC has 
determined, however, that security and mitigation measures the NRC has 
imposed upon its licensees since September 11, 2001, and national anti-
terrorist measures to prevent, for example, aircraft hijackings, 
coupled with the robust nature of SFPs, make the probability of a 
successful terrorist attack, though numerically indeterminable, very 
low.
    The NRC's regulations and security orders require licensees to 
develop security and training plans for NRC review and approval, 
implement procedures for these plans, and to periodically demonstrate 
proficiency through tests and exercises.\2\ In addition, reactor 
physical security systems use a defense-in-depth concept, involving the 
following:
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    \2\ For additional related information, please see the NRC fact 
sheet ``NRC Review of Paper on Reducing Hazards From Stored Spent 
Nuclear Fuel,'' which is available on the NRC's public Web site at: 
https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/reducing-
hazards-spent-fuel.html.
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     Vehicle (external) barriers.
     Fences.
     Intrusion detection, alarm, and assessment systems.
     Internal barriers.
     Armed responders.
     Redundant alarm stations with command, control, and 
communications systems.
     Local law enforcement authority's response to a site and 
augmentation of the on-site armed response force.
     Security and emergency-preparedness procedure development 
and planning efforts with local officials.
     Security personnel training and qualification.
    The NRC's regulatory approach for maintaining the safety and 
security of power reactors, and thus SFPs, is based upon robust designs 
that are coupled with a strategic triad of preventive/protective 
systems, mitigative systems, and emergency-preparedness and response. 
Furthermore, each licensee's security functions are integrated and 
coordinated with reactor operations and emergency response functions. 
Licensees develop protective strategies in order to meet the NRC 
design-basis threat (DBT).\3\ In addition, other Federal agencies such 
as the Federal Aviation Administration, the Federal Bureau of 
Investigation, and the Department of Homeland Security have taken 
aggressive steps to prevent terrorist attacks in the United States. 
Taken as a whole, these systems, personnel, and procedures provide 
reasonable assurance that public health and safety, the environment, 
and the common defense and security will be adequately protected.
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    \3\ The DBT represents the largest threat against which a 
private sector facility can be reasonably expected to defend with 
high assurance. The NRC's DBT rule was published in the Federal 
Register on March 19, 2007 (72 FR 12705).
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C. Very Low Risk

    Risk is defined as the probability of the occurrence of a given 
event multiplied by the consequences of that event.\4\ Studies 
conducted over the last three decades have consistently shown that the 
probability of an accident causing a zirconium fire in an SFP to be 
lower than that for severe reactor accidents. The risk of beyond 
design-basis accidents (DBAs) in SFPs was first examined as part of the 
landmark Reactor Safety Study: An Assessment of Accident Risks in U.S. 
Commercial Nuclear Power Plants (WASH-1400, NUREG-75/014, 1975), and 
was found to be several orders of magnitude below those involving the 
reactor core. The risk of an SFP accident was re-examined in the 1980's 
as Generic Issue 82, Beyond Design Basis Accidents in Spent Fuel Pools, 
in light of increased use of high-density storage racks and laboratory 
studies that indicated the possibility of zirconium fire propagation 
between assemblies in an air-cooled environment. The risk assessment 
and cost-benefit analyses developed through this effort, NUREG-1353, 
Regulatory Analysis for the Resolution of Generic Issue 82, Beyond 
Design Basis Accidents in Spent Fuel Pools, Section 6.2, April 1989, 
concluded that the risk of a severe accident in the SFP was low and 
``appear[s] to meet'' the objectives of the Commission's ``Safety Goals 
for the Operations of Nuclear Power Plants; Policy Statement,'' (August 
4, 1986; 51 FR 28044), as amended (August 21, 1986; 51 FR 30028), and 
that no new regulatory requirements were warranted.\5\
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    \4\ The American Society of Mechanical Engineers (ASME) 
``Standard for Probabilistic Risk Assessment for Nuclear Power Plant 
Applications,'' ASME RA-S-2002, defines risk as the probability and 
consequences of an event, as expressed by the risk ``triplet'' that 
is the answer to the following three questions: (1) What can go 
wrong? (2) How likely is it? and (3) What are the consequences if it 
occurs?
    \5\ The Commission's Safety Goals identified two quantitative 
objectives concerning mortality risks: (1) The risk to an average 
individual in the vicinity of a nuclear power plant of prompt 
fatalities that might result from reactor accidents should not 
exceed one-tenth of one percent (0.1 percent) of the sum of prompt 
fatality risks resulting from other accidents in which members of 
the U.S. population are generally exposed; and (2) The risk to the 
population in the area near a nuclear power plant of cancer 
fatalities that might result from nuclear power plant operation 
should not exceed one-tenth of one percent (0.1 percent) of the sum 
of cancer fatality risks resulting from all other causes.
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    SFP accident risk was re-assessed in the late 1990s to support a 
risk-informed rulemaking for permanently shutdown, or decommissioned, 
nuclear power plants. The study, NUREG-1738, Technical Study of Spent 
Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants, 
January 2001, conservatively assumed that if the water level in the SFP 
dropped below the top of the spent fuel, an SFP zirconium fire 
involving all of the spent fuel would occur, and thereby bounded those 
conditions associated with air cooling of the fuel (including partial-
draindown scenarios) and fire propagation. Even when all events leading 
to the spent fuel assemblies becoming partially or completely uncovered 
were assumed to result in an SFP zirconium fire, the study found the 
risk of an SFP fire to be low and well within the Commission's Safety 
Goals.
    Furthermore, significant additional analyses have been performed 
since September 11, 2001, that support the view that the risk of a 
successful terrorist attack (i.e., one that results in an SFP zirconium 
fire) is very low. These analyses were conducted by the Sandia National 
Laboratories and are collectively referred to herein as the ``Sandia 
studies.'' \6\ The Sandia studies

[[Page 46208]]

are sensitive security related information and are not available to the 
public. The Sandia studies considered spent fuel loading patterns and 
other aspects of a pressurized-water reactor SFP and a boiling-water 
reactor SFP, including the role that the circulation of air plays in 
the cooling of spent fuel. The Sandia studies indicated that there may 
be a significant amount of time between the initiating event (i.e., the 
event that causes the SFP water level to drop) and the spent fuel 
assemblies becoming partially or completely uncovered. In addition, the 
Sandia studies indicated that for those hypothetical conditions where 
air cooling may not be effective in preventing a zirconium fire (i.e., 
the partial drain down scenario cited by the Petitioners), there is a 
significant amount of time between the spent fuel becoming uncovered 
and the possible onset of such a zirconium fire, thereby providing a 
substantial opportunity for both operator and system event mitigation.
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    \6\ Sandia National Laboratories, ``Mitigation of Spent Fuel 
Pool Loss-of-Coolant Inventory Accidents and Extension of Reference 
Plant Analyses to Other Spent Fuel Pools,'' Sandia Letter Report, 
Revision 2 (November 2006) incorporates and summarizes the Sandia 
Studies. This document is designated ``Official Use Only--Security 
Related Information.'' A version of the Sandia Studies, with 
substantial redactions, was made public as a response to a Freedom 
of Information Act request. It is available on the NRC's Agencywide 
Document Access and Management System (ADAMS). The redacted version 
can be found under ADAMS Accession No. ML062290362. For access to 
ADAMS, contact the NRC Public Document Room Reference staff at 1-
800-397-4209, 301-415-4737, or by e-mail to pdr.resource@nrc.gov. 
For additional related information, please see the NRC fact sheet 
``NRC Review of Paper on Reducing Hazards From Stored Spent Nuclear 
Fuel,'' which is available on the NRC's public Web site at: https://
www.nrc.gov/reading-rm/doc-collections/fact-sheets/reducing-hazards-
spent-fuel.html.
---------------------------------------------------------------------------

    The Sandia studies, which more fully account for relevant heat 
transfer and fluid flow mechanisms, also indicated that air-cooling of 
spent fuel would be sufficient to prevent SFP zirconium fires at a 
point much earlier following fuel offload from the reactor than 
previously considered (e.g., in NUREG-1738). Thus, the fuel is more 
easily cooled, and the likelihood of an SFP fire is therefore reduced.
    Additional mitigation strategies implemented subsequent to 
September 11, 2001, enhance spent fuel coolability and the potential to 
recover SFP water level and cooling prior to a potential SFP zirconium 
fire. The Sandia studies also confirmed the effectiveness of additional 
mitigation strategies to maintain spent fuel cooling in the event the 
pool is drained and its initial water inventory is reduced or lost 
entirely. Based on this more recent information, and the implementation 
of additional strategies following September 11, 2001, the probability, 
and accordingly, the risk, of a SFP zirconium fire initiation is 
expected to be less than reported in NUREG-1738 and previous studies.
    Given the physical robustness of SFPs, the physical security 
measures, and SFP mitigation measures, and based upon NRC site 
evaluations of every SFP in the United States, the NRC has determined 
that the risk of an SFP zirconium fire, whether caused by an accident 
or a terrorist attack, is very low. As such, the NRC's generic findings 
in NUREG-1437, as further reflected in Table B-1 of appendix B to 
subpart A of 10 CFR part 51, remain valid.

VI. Reasons for Denial--NRC Responses to Petitioners' Assertions

A. New and Significant Information

    The Petitioners asserted that new and significant information shows 
that the NRC incorrectly characterized the environmental impacts of 
spent fuel storage as ``insignificant.'' The information relied upon by 
the Petitioners, however, is neither ``new'' nor ``significant,'' 
within the NRC's definition of those terms. The NRC defines these terms 
in its Supplement 1 to NRC Regulatory Guide 4.2, Preparation of 
Supplemental Environmental Reports for Applications to Renew Nuclear 
Power Plant Operating Licenses, Chapter 5 (September 2000) (RG 4.2S1). 
``New and significant'' information, which would require supplementing 
NUREG-1437, is defined as follows:

    (1) Information that identifies a significant environmental 
issue that was not considered in NUREG-1437 and, consequently, not 
codified in Appendix B to Subpart A of 10 CFR Part 51, or
    (2) Information that was not considered in the analyses 
summarized in NUREG-1437 and that leads to an impact finding 
different from that codified in 10 CFR Part 51.

    The Petitioners' ``new and significant'' information does not meet 
the RG 4.2S1 criteria. NUREG-1437 (Sections 6.4.6.1. to 6.4.6.3.), and 
the analyses cited therein, including the NRC's ``Waste Confidence 
Rule'' (September 18, 1990; 55 FR 38474, 38480-81), extensively 
considered the risk of SFP accidents. Moreover, to the extent any 
information submitted by the Petitioners was not considered in NUREG-
1437, none of the information is ``significant,'' because, as explained 
further in this document, it would not lead to ``an impact finding 
different from that codified in 10 CFR Part 51,'' or as set forth in 
NUREG-1437.

B. Spent Fuel Assemblies Will Burn If Uncovered

    The Petitioners asserted that new and significant information, 
consisting primarily of the Thompson Report, NUREG-1738, and a 
government-sponsored study, the NAS Report, show that spent fuel will 
burn if the water level in an SFP drops to the point where the tops of 
the fuel assemblies are uncovered. Specifically, the Petitioners 
asserted that the NRC fails to recognize the danger of a partial loss 
of water in an SFP, which in the Petitioners' view, is more likely to 
cause an SFP zirconium fire than a complete loss of water, because the 
remaining water will block the circulating air that would otherwise act 
to cool the spent fuel assemblies.
    The NRC does not agree with the Petitioners' assertions. The NRC 
has determined that a zirconium cladding fire does not occur when only 
the tops of the fuel assemblies are uncovered. In reality, a zirconium 
fire cannot occur unless fuel uncovering is more substantial. Even 
then, the occurrence of a zirconium fire requires a number of 
conditions which are extremely unlikely to occur together. The Sandia 
studies provide a more realistic assessment of the coolability of spent 
fuel under a range of conditions and a better understanding of the 
actual safety margins than was indicated in NUREG-1738. The Sandia 
studies have consistently and conclusively shown that the safety 
margins are much larger than indicated by previous studies such as 
NUREG-1738.
1. Heat Transfer Mechanisms
    Past NRC studies of spent fuel heatup and zirconium fire initiation 
conservatively did not consider certain natural heat-transfer 
mechanisms which would serve to limit heatup of the spent fuel 
assemblies and prevent a zirconium fire. In particular, these studies, 
including NUREG-1738, did not consider heat transfer from higher-decay-
power assemblies to older, lower-decay-power fuel assemblies in the 
SFP. This heat transfer would substantially increase the effectiveness 
of air cooling in the event the SFP is drained, far beyond the 
effectiveness of air cooling cited in past studies. Both the Sandia 
studies and the NAS Report confirm the NRC conclusion that such heat 
transfer mechanisms allow rapid heat transfer away from the higher-
powered assemblies. The NAS Report also noted that such heat transfer 
could air-cool the assemblies to prevent a zirconium fire within a 
relatively short time after the discharge of assemblies from the 
reactor to the SFP.\7\ Thus, air cooling is an effective, passive 
mechanism for cooling spent fuel assemblies in the pool.
---------------------------------------------------------------------------

    \7\ NAS Report at 53.
---------------------------------------------------------------------------

2. Partial Drain-Down
    Air cooling is less effective under the special, limited condition 
where the water level in the SFP drops to a point where water and steam 
cooling is not sufficient to prevent the fuel from overheating and 
initiating a zirconium fire, but the water level is high enough to 
block the full natural circulation of air flow through the assemblies. 
This condition has been commonly referred to as a partial draindown, 
and is cited in the Thompson Report. Under those

[[Page 46209]]

conditions, however, it is important to realistically model the heat 
transfer between high- and low-powered fuel assemblies. The heat 
transfer from hot fuel assemblies to cooler assemblies will delay the 
heat-up of assemblies, and allow plant operators time to take 
additional measures to restore effective cooling to the assemblies. 
Further, for very low-powered assemblies, the downward flow of air into 
the assemblies can also serve to cool the assembly even though the 
full-circulation flow path is blocked. Also, as discussed further in 
this document, all nuclear plant SFPs have been assessed to identify 
additional, existing cooling capability and to provide new supplemental 
cooling capability which could be used during such rare events. This 
supplemental cooling capability specifically addresses the cooling 
needs during partial draindown events, and would reduce the probability 
of a zirconium fire even during those extreme events.
3. License Amendments
    In January 2006, the nuclear industry proposed a combination of 
internal and external strategies to enhance the spent fuel heat removal 
capability systems at every operating nuclear power plant. The internal 
strategy implements a diverse SFP makeup system that can supply the 
required amount of makeup water and SFP spray to remove decay heat. The 
external strategy involves using an independently-powered, portable, 
SFP coolant makeup and spray capability system that enhances spray and 
rapid coolant makeup to mitigate a wide range of possible scenarios 
that could reduce SFP water levels. In addition, in cases where SFP 
water levels can not be maintained, leakage control strategies would be 
considered along with guidance to maximize spray flows to the SFP. Time 
lines have been developed that include both dispersed and non-dispersed 
spent fuel storage. The NRC has approved license amendments and issued 
safety evaluations to incorporate these strategies into the plant 
licensing bases of all operating nuclear power plants in the United 
States.

C. Fuel Will Burn Regardless of Its Age

    The NRC disagrees with the Petitioners' assertion that fuel will 
burn regardless of age. Older fuel (fuel which has been discharged from 
the reactor for a longer time) is more easily cooled and is less likely 
to ignite because of its lower decay power. A study relied upon by the 
Petitioners, NUREG-1738, did conservatively assume that spent fuel 
stored in an SFP, regardless of age, may be potentially vulnerable to a 
partial drain down event, and that the possibility of a zirconium fire 
could not be ruled out on a generic basis. This conclusion, however, 
was in no sense a statement of certainty and was made in order to reach 
a conclusion on a generic basis, without relying on any plant-specific 
analyses.
    Furthermore, the SFP zirconium fire frequency in NUREG-1738 was 
predicated on a bounding, conservative assumption that an SFP fire 
involving all of the spent fuel would occur if the water level in the 
SFP dropped below the top of the spent fuel. The NUREG-1738 analysis 
did not attempt to specifically address a number of issues and actions 
that would substantially reduce the likelihood of a zirconium fire, 
potentially rendering the frequency estimate to be remote and 
speculative. For example, NUREG-1738 did not account for the additional 
time available following the spent fuel being partially or completely 
uncovered, but prior to the onset of a zirconium fire, that would allow 
for plant operator actions, makeup of SFP water levels, and other 
mitigation measures. In addition, NUREG-1738 did not consider the 
impact of plant and procedure changes implemented as a result of the 
events of the September 11, 2001, terrorist attacks. NUREG-1738 did 
clarify that the likelihood of a zirconium fire under such conditions 
could be reduced by accident management measures, but it was not the 
purpose of NUREG-1738 to evaluate such accident management measures.

D. SFP Zirconium Fire Will Propagate

    Although it is possible that once a spent fuel assembly ignites, 
the zirconium fire can propagate to other assemblies in the SFP, the 
NRC has determined (as explained previously) that the risk of an SFP 
zirconium fire initiation is very low.

E. SFP Zirconium Fire May Be Catastrophic

1. Not New and Significant Information; Very Low Probability
    The Massachusetts AG states that ``while such a catastrophic 
accident is unlikely, its probability falls within the range that NRC 
considers reasonably foreseeable.'' Thus, the Petitioners asserted that 
an SFP zirconium fire qualifies as a DBA and, that the impacts of an 
SFP fire must be discussed in the ER submitted by the licensee and the 
NRC's EIS, as well as designed against under NRC safety regulations.
    The facts that a SFP contains a potentially large inventory of 
radionuclides and that a release of that material could have adverse 
effects are not new. These facts are well known, and were considered in 
the risk evaluation of spent fuel storage contained in NUREG-1738. Even 
with the numerous conservatisms in the NUREG-1738 study, as described 
previously, the NRC was able to conclude that the risk from spent fuel 
storage is low, and is substantially lower than reactor risk.
    A study relied upon by the Petitioners, the Thompson Report, 
claimed that the probability (frequency) of an SFP zirconium fire would 
be 2E-5 per year \8\ for events excluding acts of malice (e.g., 
terrorism) and 1E-4 per year \9\ for acts of malice. With respect to 
random events (i.e., excluding acts of malice), the NRC concludes that 
the Thompson Report estimate is overly conservative. A more complete 
and mechanistic assessment of the event, as described in section 
VI.E.2. of this Notice, and associated mitigation measures, leads to 
considerably lower values. With respect to events initiated by a 
terrorist attack, the NRC concludes that such probability (frequency) 
estimates are entirely speculative. The NRC also concludes that the 
additional mitigation measures for SFP events implemented since 
September 11, 2001, together with the more realistic assessment of 
spent fuel cooling, indicates that the likelihood of a zirconium fire, 
though numerically indeterminable, is very low.
---------------------------------------------------------------------------

    \8\ Two occurrences in 100,000 reactor years.
    \9\ One occurrence in 10,000 reactor years.
---------------------------------------------------------------------------

    The 2E-5 per year estimate for events excluding acts of malice is 
based on an unsubstantiated assumption that 50 percent of all severe 
reactor accidents that result in an early release of substantial 
amounts of radioactive material will also lead to a consequential SFP 
zirconium fire. The Thompson Report does not identify the necessary 
sequence of events by which such scenarios might lead to SFP zirconium 
fires, or discuss the probability of their occurrence. The NRC analysis 
in the Shearon Harris ASLBP proceeding (described in section VI.E.2. of 
this Notice) showed that a more complete and mechanistic assessment of 
the event and associated mitigation measures leads to considerably 
lower values. This assessment includes the following:
     Frequency and characteristics of the releases from the 
containment for each release location;
     Transport of gases and fission products within the reactor 
building;

[[Page 46210]]

     Resulting thermal and radiation environments in the 
reactor building, with emphasis on areas in which SFP cooling and 
makeup equipment is located, and areas in which operator access may be 
needed to implement response actions;
     Availability/survivability of SFP cooling and makeup 
equipment in the sequences of concern; and
     Ability and likelihood of successful operator actions to 
maintain or restore pool cooling or makeup (including consideration of 
security enhancements and other mitigation measures implemented in 
response to the terrorist attacks of September 11, 2001).
2. Shearon Harris Atomic Safety and Licensing Board Panel (ASLBP) 
Proceeding
    In the proceeding regarding the expansion of the SFP at the Shearon 
Harris nuclear power plant, located near Raleigh, North Carolina, the 
Shearon Harris intervenor described a scenario similar to that raised 
by the Petitioners, namely, that a severe accident at the adjacent 
reactor would result in a SFP zirconium fire.\10\ The Shearon Harris 
proceeding considered the probability of a sequence of the following 
seven events:
---------------------------------------------------------------------------

    \10\ Carolina Power Light Co., LBP-01-9, 53 NRC 239, 244-245 
(2001).
---------------------------------------------------------------------------

    a. A degraded core accident.
    b. Containment failure or bypass.
    c. Loss of SFP cooling.
    d. Extreme radiation levels precluding personnel access.
    e. Inability to restart cooling or makeup systems due to extreme 
radiation doses.
    f. Loss of most or all pool water through evaporation.
    g. Initiation of a zirconium fire in the SFP.
    Based on a detailed probabilistic risk assessment, the licensee 
calculated the probability of a severe reactor accident that causes an 
SFP zirconium fire to be 2.78E-8 per year. The NRC staff calculated the 
probability to be 2.0E-7 per year. The intervenor calculated the 
probability to be 1.6E-5 per year. The ASLBP concluded that the 
probability of the postulated sequence of events resulting in an SFP 
zirconium fire was ``conservatively in the range described by the 
Staff: 2.0E-7 per year (two occurrences in 10 million reactor years) or 
less.'' \11\ Accordingly, the ASLBP found that the occurrence of a 
severe reactor accident causing an SFP zirconium fire ``falls within 
the category of remote and speculative matters.'' \12\ The Commission 
affirmed the ASLBP's decision, and the United States Court of Appeals, 
District of Columbia Circuit, upheld the Commission decision.\13\
---------------------------------------------------------------------------

    \11\ Id., 53 NRC at 267.
    \12\ Id., 53 NRC at 268.
    \13\ Carolina Power Light Co., Commission Law Issuance (CLI)-01-
11, 53 NRC 370 (2001), pet. for review denied, sub nom, Orange 
County, NC v. NRC, 47 Fed. Appx. 1, 2002 WL 31098379 (D.C. Cir. 
2002).
---------------------------------------------------------------------------

    In the Shearon Harris proceeding, the intervenor assumed that, 
given an early containment failure or bypass, a spent fuel zirconium 
fire would occur (i.e., a conditional probability of 1.0). In order for 
a reactor accident to lead to a SFP zirconium fire a number of 
additional conditions must occur. The reactor accident and containment 
failure must somehow lead to a loss of SFP cooling and must lead to a 
condition where extreme radiation levels preclude personnel access to 
take corrective action. There must be then an inability to restart 
cooling or makeup systems. There must be a loss of significant pool 
water inventory through evaporation (which can take substantial time). 
Finally, the event must also lead to a zirconium fire. In contrast to 
the intervenor's estimate, the licensee and the NRC staff estimated a 
conditional probability of about one percent that a severe reactor 
accident with containment failure would lead to a SFP accident. The NRC 
staff expects that the conditional probability of a SFP zirconium fire, 
given a severe reactor accident, would be similar to that established 
in the Shearon Harris proceeding. As such, the probability of a SFP 
zirconium fire due to a severe reactor accident and subsequent 
containment failure would be well below the Petitioners' 2E-5 per year 
estimate.
    The 1E-4 per year estimate in the Thompson Report for events 
involving acts of malice assumes that there would be one attack on the 
population of U.S. nuclear power plants per century, and that this 
attack will be 100 percent successful in producing a SFP zirconium fire 
(thus, fire frequency = 0.01 attack/year x 1.0 fire/attack x 1/104 
total reactors = 1E-4/year). The security-related measures and other 
mitigation measures implemented since September 11, 2001, however, have 
significantly reduced the likelihood of a successful terrorist attack 
on a nuclear power plant and its associated SFP. Such measures include 
actions that would improve the likelihood of the following:
    a. Identifying/thwarting the attack before it is initiated.
    b. Mitigating the attack before it results in damage to the plant.
    c. Mitigating the impact of the plant damage such that an SFP 
zirconium fire is avoided.
    Given the implementation of additional security enhancements and 
mitigation strategies, as well as further consideration of the factors 
identified above, the NRC staff concludes that the frequency of SFP 
zirconium fires due to acts of malice is substantially lower than 
assumed by the Petitioners.
3. SFP Zirconium Fire Does Not Qualify As a DBA
    Regarding the Petitioners' assertion that a SFP zirconium fire 
qualifies as a design-basis accident (DBA), the NRC staff has concluded 
that a realistic probability estimate would be very low, such that 
these events need not be considered as DBAs or discussed in ERs and 
EISs. Moreover, the set of accidents that must be addressed as part of 
the design basis has historically evolved from deterministic rather 
than probabilistic considerations. These considerations, which include 
defense-in-depth, redundancy, and diversity, are characterized by the 
use of the single-failure criterion.\14\ The single-failure criterion, 
as a key design and analysis tool, has the direct objective of 
promoting reliability through the enforced provision of redundancy in 
those systems which must perform a safety-related function. The single 
failure criterion is codified in Appendix A and Appendix K to 10 CFR 
Part 50 and other portions of the regulations. The SFP and related 
systems have been designed and approved in accordance with this 
deterministic approach.
---------------------------------------------------------------------------

    \14\ ``A single failure means an occurrence which results in the 
loss of capability of a component to perform its intended safety 
functions * * * Fluid and electric systems are considered to be 
designed against an assumed single failure if neither (1) a single 
failure of any active component * * * nor (2) a single failure of a 
passive component * * * results in a loss of the capability of the 
system to perform its safety functions.'' 10 CFR Part 50, App. A.
---------------------------------------------------------------------------

F. Intentional Attack on a SFP is ``Reasonably Foreseeable.''

    The Petitioners asserted that an intentional attack targeting a 
plant's SFP is ``reasonably foreseeable.'' Specifically, the 
Petitioners raised both the NAS study and the decision by the United 
States Court of Appeals for the Ninth Circuit, San Luis Obispo Mothers 
for Peace v. NRC, 449 F.3d 1016 (9th Cir. 2006), cert. denied 127 S. 
Ct. 1124 (2007), to support the assertion that the NRC's NEPA analysis 
of a license renewal action for a given facility must include analysis 
of the environmental impacts associated with a terrorist attack on that 
facility. The NRC has

[[Page 46211]]

considered both the NAS Report and the Ninth Circuit decision, and 
remains of the view that an analysis of the environmental impacts of a 
hypothetical terrorist attack on an NRC-licensed facility is not 
required under NEPA.\15\ But, if an analysis of a hypothetical 
terrorist attack were required under NEPA, the NRC has determined that 
the environmental impacts of such a terrorist attack would not be 
significant, because the probability of a successful terrorist attack 
(i.e., one that causes an SFP zirconium fire, which results in the 
release of a large amount of radioactive material into the environment) 
is very low and therefore, within the category of remote and 
speculative matters.
---------------------------------------------------------------------------

    \15\ In the wake of the Ninth Circuit's Mothers for Peace 
decision, the Commission decided against applying that holding to 
all licensing proceedings nationwide. See, e.g., Amergen Energy Co. 
LLC (Oyster Creek Nuclear Generating Station), CLI-07-8, 65 NRC 124, 
128-29 (2007), pet. for judicial review pending, No. 07-2271 (3d 
Cir.). The Commission will, of course, adhere to the Ninth Circuit 
decision when considering licensing actions for facilities subject 
to the jurisdiction of that Circuit. See id. Thus, on remand in the 
Mothers for Peace case itself, the Commission is currently 
adjudicating intervenors' claim that the NRC Staff has not 
adequately assessed the environmental consequences of a terrorist 
attack on the Diablo Canyon Power Plant's proposed facility for 
storing spent nuclear fuel in dry casks. See, Pacific Gas & Elec. 
Co., CLI-07-11, 65 NRC 148 (2007). The Commission's ultimate 
decision in that case will rest on the record developed in the 
adjudication.
---------------------------------------------------------------------------

1. NAS Report
    The Petitioners rely, in part, upon the NAS Report, the public 
version of which was published in 2006 and is available from NAS.\16\ 
In response to a direction in the Conference Committee's Report 
accompanying the NRC's FY 2004 appropriation,\17\ the NRC contracted 
with NAS for a study on the safety and security of commercial spent 
nuclear fuel. The NAS made a number of findings and recommendations, 
including:
---------------------------------------------------------------------------

    \16\ The NRC response to the NAS Report is available at ADAMS 
Accession No. ML0502804280.
    \17\ Conference Committee's Report (H. Rept. 108-357) 
accompanying the Energy and Water Development Act, 2004 (Pub. L. 
108-137, December 3, 2003).
---------------------------------------------------------------------------

     SFPs are necessary at all operating nuclear power plants 
to store recently discharged fuel;
     Successful terrorist attacks on SFPs, though difficult, 
are possible;
     The probability of terrorist attacks on spent fuel storage 
cannot be assessed quantitatively or comparatively;
     If a successful terrorist attack leads to a propagating 
zirconium cladding fire, it could result in the release of large 
amounts of radioactive material; and
     Dry cask storage has inherent security advantages over 
spent fuel storage, but it can only be used to store older spent fuel.
    The NAS Report found, and the NRC agrees, that pool storage is 
required at all operating commercial nuclear power plants to cool newly 
discharged spent fuel. Freshly discharged spent fuel generates too much 
decay heat to be placed in a dry storage cask.
    The NRC agrees with the NAS finding that the probability of 
terrorist attacks on spent fuel storage cannot be assessed 
quantitatively or comparatively. However, the NRC concludes that the 
additional mitigation measures for SFP events implemented since 
September 11, 2001, together with a more realistic assessment of spent 
fuel cooling, as shown by the Sandia studies, indicates that the 
likelihood of a zirconium fire, though numerically indeterminate, is 
very low.
    Furthermore, the NAS Report states that ``[i]t is important to 
recognize, however, that an attack that damages a power plant or its 
spent fuel storage facilities would not necessarily result in the 
release of any radioactivity to the environment. There are potential 
steps that can be taken to lower the potential consequences of such 
attacks.'' \18\ The NAS Report observed that a number of security 
improvements at nuclear power plants have been instituted since 
September 11, 2001, although the NAS did not evaluate the effectiveness 
and adequacy of these improvements and has called for an independent 
review of such measures. Nevertheless, the NAS Report states that ``the 
facilities used to store spent fuel at nuclear power plants are very 
robust. Thus, only attacks that involve the application of large energy 
impulses or that allow terrorists to gain interior access have any 
chance of releasing substantial quantities of radioactive material.'' 
\19\
---------------------------------------------------------------------------

    \18\ NAS Report at 6 (emphasis in the original).
    \19\ NAS Report at 30.
---------------------------------------------------------------------------

    As discussed previously, following the terrorist attacks of 
September 11, 2001, the NRC has required that nuclear power plant 
licensees implement additional security measures and enhancements the 
Commission believes have made the likelihood of a successful terrorist 
attack on an SFP remote.
2. Ninth Circuit Decision
    The Petitioners asserted that the NRC should follow the decision of 
the United States Court of Appeals for the Ninth Circuit, San Luis 
Obispo Mothers for Peace v. NRC, 449 F.3d 1016 (9th Cir. 2006), cert. 
denied 127 S. Ct. 1124 (2007), by considering the environmental impacts 
of intentional attacks on nuclear power plant fuel storage pools in all 
licensing decisions. The Ninth Circuit held that the NRC could not, 
under NEPA, categorically refuse to consider the consequences of a 
terrorist attack against a spent fuel storage facility on the Diablo 
Canyon reactor site.
    The NRC's longstanding view is that NEPA does not require the NRC 
to consider the environmental consequences of hypothetical terrorist 
attacks on NRC-licensed facilities. NEPA requires that there be a 
``reasonably close causal relationship'' between the federal agency 
action and the environmental consequences.\20\ The NRC renewal of a 
nuclear power plant license would not cause a terrorist attack; a 
terrorist attack would be caused by the terrorists themselves. Thus, 
the renewal of a nuclear power plant license would not be the 
``proximate cause'' of a terrorist attack on the facility.
---------------------------------------------------------------------------

    \20\ Department of Transportation v. Public Citizen, 541 U.S. 
752, 767 (2004) citing Metropolitan Edison v. People Against Nuclear 
Energy, 460 U.S. 766, 774 (1983).
---------------------------------------------------------------------------

    If NEPA required the NRC to consider the impacts of a terrorist 
attack, however, the NRC findings would remain unchanged. As previously 
described, the NRC has required, and nuclear power plant licensees have 
implemented, various security and mitigation measures that, along with 
the robust nature of SFPs, make the probability of a successful 
terrorist attack (i.e., one that causes an SFP zirconium fire, which 
results in the release of a large amount of radioactive material into 
the environment) very low. As such, a successful terrorist attack is 
within the category of remote and speculative matters for NEPA 
considerations; it is not ``reasonably foreseeable.'' Thus, on this 
basis, the NRC finds that the environmental impacts of renewing a 
nuclear power plant license, in regard to a terrorist attack on an SFP, 
are not significant.
    The NRC has determined that its findings related to the storage of 
spent nuclear fuel in pools, as set forth in NUREG-1437 and in Table B-
1 of Appendix B to Subpart A of 10 CFR Part 51, remain valid. Thus, the 
NRC has met and continues to meet its obligations under NEPA.

G. SFP Zirconium Fire Should Be Considered Within the Analysis of SAMAs

    The Petitioners asserted that SFP fires should be considered within 
the analysis of severe accident mitigation alternatives (SAMAs). While 
a large radiological release is still possible, and

[[Page 46212]]

was assessed as part of Generic Issue 82, Beyond Design Basis Accidents 
in Spent Fuel Pools, and later, in NUREG-1738, the NRC considers the 
likelihood of such an event to be lower than that estimated in Generic 
Issue 82 and NUREG-1738. Based on the Sandia studies, and on the 
implementation of additional strategies implemented following September 
11, 2001, the probability of a SFP zirconium fire is expected to be 
less than that reported in NUREG-1738 and previous studies. Thus, the 
very low probability of an SFP zirconium fire would result in an SFP 
risk level less than that for a reactor accident.
    For example, in NUREG-1738, the SFP fire frequencies were 
conservatively estimated to be in the range of 5.8E-7 per year to 2.4E-
6 per year. NUREG-1738 conservatively assumed that if the water level 
in the SFP dropped below the top of the spent fuel, an SFP zirconium 
fire involving all of the spent fuel would occur, and thereby bounded 
those conditions associated with air cooling of the fuel (including 
partial-drain down scenarios) and zirconium fire propagation. It did 
not mechanistically analyze the time between the spent fuel assemblies 
becoming partially or completely uncovered and the onset of a SFP 
zirconium fire, and the potential to recover SFP cooling and to restore 
the SFP water level within this time. NUREG-1738 also did not consider 
the possibility that air-cooling of the spent fuel alone could be 
sufficient to prevent SFP zirconium fires.
    Furthermore, the Sandia studies indicated that air cooling would be 
much more effective in cooling the spent fuel assemblies. In those 
cases where air cooling is not effective, the time before fuel heatup 
and radiological release would be substantially delayed, thus providing 
a substantial opportunity for successful event mitigation. The Sandia 
studies, which more fully account for relevant heat transfer and fluid 
flow mechanisms, also indicated that air-cooling of spent fuel would be 
sufficient to prevent SFP zirconium fires much earlier following fuel 
offload than previously considered (e.g., in NUREG-1738), thereby 
further reducing the likelihood of an SFP zirconium fire. Additional 
mitigation strategies implemented su