[Federal Register Volume 81, Number 196 (Tuesday, October 11, 2016)]
[Rules and Regulations]
[Pages 70004-70011]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-24466]


=======================================================================
-----------------------------------------------------------------------

NUCLEAR REGULATORY COMMISSION

10 CFR Part 72

[NRC-2015-0270]
RIN 3150-AJ71


List of Approved Spent Fuel Storage Casks: Holtec International 
HI-STORM 100 Cask System; Certificate of Compliance No. 1014, Amendment 
No. 10

AGENCY: Nuclear Regulatory Commission.

ACTION: Direct final rule; comment responses.

-----------------------------------------------------------------------

SUMMARY: On May 31, 2016, the U.S. Nuclear Regulatory Commission (NRC) 
confirmed the effective date of May 31, 2016, for the direct final rule 
that was published in the Federal Register on March 14, 2016. The 
direct final rule amended the NRC's spent fuel storage regulations by 
revising the Holtec International (Holtec) HI-STORM 100 Cask System 
listing within the ``List of approved spent fuel storage casks'' to 
include Amendment No. 10 to Certificate of Compliance (CoC) No. 1014. 
The NRC confirmed the effective date because it determined that none of 
the comments submitted on the direct final rule met any of the criteria 
for a significant adverse comment. The purpose of this document is to 
provide responses to the comments received on the direct final rule.

DATES: The comment responses are available on October 11, 2016.

ADDRESSES: Please refer to Docket ID NRC-2015-0270 when contacting the 
NRC about the availability of information for this action. You may 
obtain publicly-available information related to this action by any of 
the following methods:
     Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2015-0270. Address 
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; email: [email protected]. For technical questions, contact 
the individual listed in the FOR FURTHER INFORMATION CONTACT section of 
this document.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly-available documents online in the 
ADAMS Public Documents collection at http://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and 
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS, 
please contact the NRC's Public Document Room (PDR) reference staff at 
1-800-397-4209, 301-415-4737, or by email to [email protected].
     NRC's PDR: You may examine and purchase copies of public 
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 
Rockville Pike, Rockville, Maryland 20852.

FOR FURTHER INFORMATION CONTACT: Robert MacDougall, Office of Nuclear 
Material Safety and Safeguards, U.S. Nuclear Regulatory Commission, 
Washington, DC 20555-0001; telephone: 301-415-5175; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

I. Background

    On March 14, 2016 (81 FR 13265), the NRC published a direct final 
rule amending its regulations in Sec.  72.214 of title 10 of the Code 
of Federal Regulations (10 CFR) by revising the Holtec HI-STORM 100 
Cask System listing within the ``List of approved spent fuel storage 
casks'' to include Amendment No. 10 to CoC No. 1014. Amendment No. 10 
adds new fuel classes to the contents approved for the loading of 16 x 
16 class fuel assemblies into a HI-STORM 100 Cask System; allows a 
minor increase in manganese in an alloy material for the system's 
overpack and transfer cask; clarifies the minimum water displacement 
required of a dummy fuel rod (i.e., a rod not filled with uranium 
pellets); and clarifies the design pressures needed for normal 
operation of forced helium drying systems. Additionally, Amendment No. 
10 revises Condition No. 9 of CoC No. 1014 to provide clearer direction 
on the measurement of air velocity and modeling of heat distribution 
through the storage system.
    The NRC received four comment submissions with 22 individual 
comments on the companion proposed rule (81 FR 13295; March 14, 2016). 
Electronic copies of these comments can be obtained from the Federal 
Rulemaking Web site, http://www.regulations.gov, by searching for 
Docket ID NRC-2015-0270. The comments are also available in ADAMS under 
Accession Nos. ML16105A426, ML16105A425, ML16105A424, and ML16105A423. 
As explained in the March 14, 2016, direct final rule, the

[[Page 70005]]

NRC would withdraw the direct final rule only if it received a 
``significant adverse comment.'' This is a comment where the commenter 
explains why the rule would be inappropriate, including challenges to 
the rule's underlying premise or approach, or would be ineffective or 
unacceptable without a change. A comment is adverse and significant if:
    (1) The comment opposes the rule and provides a reason sufficient 
to require a substantive response in a notice-and-comment process. For 
example, a substantive response is required when:
    (a) The comment causes the NRC staff to reevaluate (or reconsider) 
its position or conduct additional analysis;
    (b) The comment raises an issue serious enough to warrant a 
substantive response to clarify or complete the record; or
    (c) The comment raises a relevant issue that was not previously 
addressed or considered by the NRC staff.
    (2) The comment proposes a change or an addition to the rule, and 
it is apparent that the rule would be ineffective or unacceptable 
without incorporation of the change or addition.
    (3) The comment causes the NRC staff to make a change (other than 
editorial) to the rule, CoC, or Technical Specifications (TSs).
    The NRC determined that none of the comments submitted on the 
direct final rule met any of these criteria and confirmed the effective 
date of May 31, 2016, for the direct final rule on May 31, 2016 (81 FR 
34241). The comments either were already addressed by the NRC staff's 
preliminary safety evaluation report (SER) (ADAMS Accession No. 
ML15331A309) for this rulemaking, were beyond the scope of this 
rulemaking, or were already addressed in a previous rulemaking. The NRC 
did not make any changes to the direct final rule as a result of the 
public comments. However, in Section II, ``Public Comment Analysis,'' 
of this document, the NRC is taking this opportunity to respond to the 
comments in an effort to clarify information about the 10 CFR part 72 
CoC rulemaking process.

II. Public Comment Analysis

    For rulemakings amending or revising a CoC, the scope of the 
rulemaking is limited to the specific changes in the applicant's 
request for the amendment or amendment revision. Therefore, comments 
about the system or spent fuel storage in general that are not 
applicable to the changes requested are outside the scope of this 
rulemaking. Comments about details of the particular system subject to 
the rulemaking that do not address the rulemaking's specific proposed 
changes have already been resolved in prior rulemakings. Persons who 
have concerns about prior rulemakings and the resulting final rules may 
consider the NRC's process for petitions for rulemaking under 10 CFR 
2.802. Additionally, safety concerns about any NRC-regulated activity 
may be reported to the NRC in accordance with the guidance posted on 
the NRC's Web site at http://www.nrc.gov/about-nrc/regulatory/allegations/safety-concern.html. This Web page provides information on 
how to notify the NRC of emergency or non-emergency issues.
    The following paragraphs summarize each individual comment followed 
by the NRC response.
    Comment 1: Noting that this is Holtec's tenth request to amend CoC 
No. 1014 for the HI-STORM 100 Cask System, one commenter stated that 
many people find this pattern disturbing. The nine earlier amendments 
and revisions to CoC No. 1014 suggest that Holtec's overall performance 
in achieving technical accuracy has been poor, not only in the 
originally-submitted TSs and quality assurance (QA) for this cask, but 
in the nine subsequent amendments and revisions that the NRC has 
approved. Because this is Holtec's tenth amendment, this commenter 
asserted that Holtec has failed to address the full range of the cask's 
technical deficiencies comprehensively, and appears instead to have 
applied the needed QA only in incremental steps.
    NRC Response: This comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The NRC is providing a specific 
response, however, to clarify the NRC's process for issuing and 
amending CoCs for dry storage system (DSS) casks.
    When the NRC first approves a CoC for a particular storage cask 
design, the CoC is based on a postulated generic spent fuel design 
using a composite of fuel characteristics and engineered features of 
the DSS. Important fuel characteristics include the level of the 
uranium enrichment in the fuel pellets and their burnup time in the 
reactor. Fuel assembly variables include the composition of the alloys 
used in the fuel cladding and assembly hardware; the diameter, number, 
and length of the fuel rods; and the spacing between them. These fuel 
characteristics and assembly design variables affect the overall heat 
load that the cask and multipurpose canister (MPC) holding the fuel 
assemblies inside the cask must be able to withstand, with a 
conservative margin of safety, to maintain their integrity for long-
term storage under normal, off-normal, and accident conditions. The 
residual heat and level of uranium burnup in the spent fuel, and the 
spacing of the fuel in the assemblies, in turn affect the number of 
fuel assemblies that can be loaded into the MPC, which must have 
internal components tailored to maintain the configuration of the fuel 
in the canister. Burnup also affects the composition and physical 
configuration of the neutron-absorbing materials arranged around the 
assemblies within the MPC. Each of these considerations must be 
evaluated with each fuel design to ensure the long-term performance of 
the overall cask system with an adequate margin of safety.
    Fuel and fuel assembly designs have evolved since each storage cask 
design was originally certified by the NRC. Contemporary fuel assembly 
designs now differ in several important respects from the generic 
designs postulated for the casks' original CoCs. To save costs and 
reduce worker exposures to radiation, for example, many contemporary 
assembly designs are optimized for fuel with higher enrichment levels 
to stay in the reactor's core to ``burn,'' or fission, a larger 
fraction of uranium for a longer period. This produces fewer spent fuel 
assemblies per unit of power generated. It also stretches out the time 
between re-fuelings, when workers need to remove the reactor's head to 
load new fuel assemblies, off-load used ones, and rearrange partially-
burned assemblies to maintain the efficiency of the overall fuel burnup 
within the reactor core. To accommodate the changes in fuel enrichment, 
fuel cladding materials, and fuel assembly materials and 
configurations, a similar evolution is continuing in MPC componentry, 
including neutron-absorbing alloys and other materials, so that casks 
can safely accept evolving fuel designs.
    Therefore, the nine amendments to CoC No. 1014, like amendments to 
other CoCs, each represent an NRC safety finding about the vendor's 
analysis of proposed measures to adapt the cask to a new fuel design 
for long-term storage. The nine amendments, and the tenth issued in May 
2016, are not the product of trial and error, nor of the incremental 
application of QA, which must be applied in a safety-graded fashion to 
all aspects of cask design, fabrication, loading, and deployment.
    The NRC made no changes to the rule as a result of this comment.
    Comment 2: One commenter asserted that in the absence of actual 
evidence

[[Page 70006]]

from operational experience or testing, using computer models to 
estimate a system's behavior or performance has produced ``extreme 
failures'' and ``major departures between [the computer model's] 
predictions and [the system's] actual performance.'' These departures, 
the commenter stated, resulted in a January 2012, radiation release at 
San Onofre Nuclear Generating Station's (SONGS) Unit 2 that eventually 
led to its premature retirement.
    NRC Response: This comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The commenter does not identify an 
issue related to any of the specific revisions proposed in Amendment 
No. 10 to CoC No. 1014. Instead, this comment is about a reactor 
licensee's computer models for the performance of a reactor system, not 
the cask vendor's models for the performance of the HI-STORM 100 Cask 
System at issue in this rulemaking. Different types of computer models 
are typically validated using different methods. The NRC uses industry 
accepted practices to evaluate an applicant's computational modeling 
software for storage casks in accordance with Interim Staff Guidance 
SFST-ISG-21, ``Use of Computational Modeling Software'' (ADAMS 
Accession No. ML061080669). Because Amendment No. 10 does not involve 
computational modeling for reactor systems, the comment is not within 
the scope of this rulemaking.
    As the commenter pointed out, there was a radiation release to the 
environment at SONGS in January 2012. This comment too is about an 
issue beyond the scope of this rulemaking. The commenter can obtain 
more information about the release, which was well below allowable 
limits, in Southern California Edison's (SCE) report to the NRC on the 
incident (ADAMS Accession No. ML12090A153), and a report by the NRC 
Office of the Inspector General (ADAMS Accession No. ML14276A478).
    The NRC made no changes to the rule as a result of this comment.
    Comment 3: One commenter stated that the proposed CoC amendment 
pertains to the same or similar Holtec cask as that to be installed at 
SONGS, and southern California stakeholders are ``extremely 
disappointed'' that SONGS' licensee, SCE, has chosen Holtec's \5/8\'' 
thin metal cask over 14''-to-20'' thick casks that the commenter stated 
can be inspected in real time to monitor the condition of the spent 
fuel and measure the depth of stress corrosion cracking.
    NRC Response: This comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The commenter does not identify an 
issue related to any of the specific revisions proposed in Amendment 
No. 10 to CoC No. 1014, and this rulemaking does not concern SCE's 
choice of cask products. In addition, the NRC has not approved any 
spent fuel dry storage cask design that permits the continuous real 
time inspection or monitoring of the condition of the fuel in the cask, 
or the continuous or periodic direct measurement of the extent or depth 
of stress corrosion cracking. Such inspection, monitoring, and 
measurement cannot be accomplished without the additional worker 
radiation exposures that would be necessary to open the cask overpack 
and canister. The NRC's regulation at 10 CFR 20.1101(b), however, 
requires radiation doses to workers and members of the public to be as 
low as is reasonably achievable. This makes such additional exposures 
to open casks and overpacks difficult to justify in light of the very 
slow rates of degradation in the cask system and its contents that have 
been measured under realistic conditions in a laboratory.
    The commenter's description of Holtec's product as a ``\5/8\'' thin 
metal cask,'' however, compels a response for clarification purposes. 
The comment appears to conflate the MPC, which is not a cask, with the 
entirety of the HI-STORM dry cask storage system. The HI-STORM 100 MPC, 
which has \1/2\'' thick stainless steel walls, holds the spent fuel 
assemblies and their hardware within an overpack. The overpack consists 
of outer and inner steel walls with the annulus between them filled 
with concrete. The overpack, with 29\1/2\'' thick concrete and steel 
walls, provides radiation shielding and mass for stability against such 
natural phenomena as winds, floods, and earthquakes. The MPC, an 
internal component of the cask system, is not directly exposed to these 
outside phenomena.
    The NRC made no changes to the rule as a result of this comment.
    Comment 4: One commenter stated that the NRC has ``mostly 
`dismissed' multiple credible public safety concerns.'' The commenter 
also noted that SCE's ``Community Engagement Panel'' has failed to 
function as an independent advisory panel of experts, and instead 
``functions more as a promotional extension of [SCE's] marketing and 
media platforms.''
    NRC Response: These comments are not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The commenter did not identify any of 
the ``multiple credible public safety concerns'' that the NRC is said 
to have dismissed. Nor did the commenter explain how any of these 
concerns pertain to any specific revision proposed in Amendment No. 10 
to CoC No. 1014.
    The NRC made no changes to the rule as a result of these comments.
    Comment 5: One commenter asserted that many stakeholders believe 
that the NRC has allowed ``a utility to improperly apply credit for 
performing an `educational' function'' that has involved, among other 
things, ``extensive private meetings with elected officials in adjacent 
communities in San Diego and Orange County.''
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. In addition, the NRC's safety-focused 
mission does not include authority to allow or prohibit a licensee from 
engaging in public relations activities, which do not directly relate 
to the design, fabrication, configuration, loading, or deployment of 
the dry cask storage system at issue here.
    The NRC made no changes to the rule as a result of this comment.
    Comment 6: A commenter stated that many stakeholders are asserting 
that SONGS licensee, SCE, ``consistently underestimates'' the actual 
extent of potential public safety risks associated with its 
decommissioning plan.
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The SCE's decommissioning plan does 
not pertain to the specific revisions proposed in Amendment No. 10 to 
CoC No. 1014; nor does the comment identify any specific potential 
public safety risks pertinent to the other purposes of this amendment.
    The NRC has a safety hotline that members of the public can use to 
report any identified public safety risk, such as may be associated 
with any decommissioning action. The hotline number is 1-800-695-7403. 
Note that a call during normal business hours (7:00 a.m. to 5:00 p.m., 
Eastern Time) will automatically be directed to the NRC Regional Office 
for the caller's geographical area. If the call is placed after normal 
business hours, or can't be

[[Page 70007]]

answered by the Regional Office during its normal business hours, the 
call will be directed to the NRC's Headquarters Operations Center, 
which is staffed 24 hours a day and has a recorded telephone line.
    The NRC made no changes to the rule as a result of this comment.
    Comment 7: A commenter stated that the licensee expecting to 
acquire the Holtec casks subject to Amendment No. 10 for spent fuel 
storage at SONGS has ``severely overestimated performance capabilities 
of equipment, components and parts, defense in depth, operator 
training, emergency response capability, system reliability, cost 
containment, and technical capability to safely implement Aging 
Management Programs.''
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. As noted in the response to Comment 
6, the NRC has a safety hotline that members of the public can use to 
report any identified public safety risk.
    The NRC made no changes to the rule as a result of this comment.
    Comment 8: Noting the ``large inventory'' of high-burnup fuel (HBF) 
in storage at SONGS, a commenter stated that stakeholders have 
``extreme safety concerns'' about the accuracy of the predicted service 
life of the Holtec underground maximum capacity (UMAX) casks containing 
HBF, which typically has higher heat loads and radiation levels. Among 
these concerns, the commenter explained, are ``thermal tolerance 
variability, measurement of air velocity, modeling of heat load 
distribution, performance capability and integrity of fuel cladding.''
    This commenter also stated that with the applicant's proposed 
changes in the composition of alloy material in MPC componentry, 
stakeholders have concerns about the accuracy of predicted helium 
pressure limits for the MPC in underground installations where closed 
loop forced helium dehydration (FHD) is mandatory for drying MPCs with 
one or more HBF assemblies or a higher heat load.
    NRC Response: The comment about HBF storage at SONGS is not within 
the scope of this rulemaking, which is limited to the specific 
revisions proposed in Amendment No. 10 to CoC No. 1014. None of these 
revisions included a change in spent fuel burnup specifications. The 
comment is about the HI-STORM UMAX Canister Storage system, which was 
authorized generically for underground emplacement under CoC No. 1040 
and approved on March 6, 2015 (80 FR 12073). The SONGS will be 
utilizing cask systems specified by Amendment No. 1 to CoC No. 1040, 
not Amendment No. 10 to CoC No. 1014.
    The commenter also expressed concerns about the accuracy of 
predicted helium pressure limits for the MPC where closed loop forced 
FHD is mandatory for drying MPCs with one or more HBF assemblies or a 
higher heat load. The comment does not explain the basis for the 
commenter's concern about the predicted pressure limit for drying. This 
limit was established to provide an ample safety margin against both 
inadequate pressure for thorough drying and excessive pressure that 
could result in damage to the spent fuel or other hardware. To maintain 
this margin, helium pressure limits are controlled during FHD 
operations at all times. During FHD drying, the MPC's inlet (drain 
port) and exit (vent port) each have calibrated pressure-indicating 
devices that show inlet and outlet pressure during drying operations. 
Trained operators use the helium regulator in accordance with the 
site's procedures to ensure that the 75-psi limit is not exceeded.
    The NRC made no changes to the rule as a result of this comment.
    Comment 9: One stakeholder stated that despite Holtec's unproven 
assurances about the performance capabilities of its casks, a 2015 
Sandia National Laboratory report contained evidence that similar thin-
metal casks had through-wall cracks in only 5 years.
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The Sandia National Laboratory report 
referred to by the commenter was for a set of design specifications for 
a Standardized Transportation, Aging, and Disposal (STAD) canister for 
eventual emplacement in a geologic repository (ADAMS Accession No. 
ML16132A321). The NRC could find nothing in this report to support the 
commenter's assertion that it ``contained evidence that similar thin 
metal casks had through-wall cracks in only 5 years.''
    The NRC made no changes to the rule as a result of this comment.
    Comment 10: As evidence that Holtec casks are ``an inferior 
choice'' for spent fuel storage, one commenter, speaking for 
``stakeholders in California,'' referred the NRC to the Web site 
``sanonofresafety.org.''
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014 and does not concern SCE's choice of 
cask products. Beyond the issue of SCE's choice, if the commenter has 
concerns about prior spent fuel storage cask rulemakings, or other 
issues beyond the scope of this rulemaking that make Holtec casks ``an 
inferior choice,'' the commenter may consider the NRC's process for 
petitions for rulemaking under 10 CFR 2.802. Additionally, safety 
concerns about any NRC-regulated activity may be reported to the NRC in 
accordance with the guidance posted on the NRC's Web site at http://www.nrc.gov/about-nrc/regulatory/allegations/safety-concern.html. This 
Web page provides information on how to notify the NRC of emergency or 
non-emergency issues.
    The NRC made no changes to the rule as a result of this comment.
    Comment 11: One commenter criticized the NRC for giving in to 
Holtec's corporate lawyers and failing to hold the company responsible 
for ``creating inadequate safety measures within this [cask] design.'' 
The commenter exhorted the NRC to ``stop paying for fraud'' and force 
Holtec to ``spend [its] own treasure . . ., not tax dollars,'' to fix 
the problem.
    NRC Response: This comment does not provide sufficient information 
to identify the ``inadequate safety measures'' in the Holtec cask's 
design that the commenter has in mind. With respect to the concern 
regarding payment for the NRC's review and oversight, these functions 
are not performed at taxpayers' expense. The vendor, in this case 
Holtec, pays for the NRC's evaluation of the application, as the NRC 
bills the vendor for the review.
    The NRC made no changes to the rule as a result of this comment.
    Comment 12: A commenter expressed concern that in permitting a cask 
system to accept additional classes of spent fuel, the NRC does not 
decrease the ability of these storage systems to contain the fuel under 
adverse conditions. The commenter wanted to know whether current 
requirements for the durability of spent fuel storage systems are 
sufficient to contain these additional fuels, whatever they may be, in 
the event of a disaster.
    NRC Response: The general issue of the durability of spent fuel 
storage systems to contain additional types of spent fuel in the event 
of a disaster is not within the scope of this rulemaking, which is 
limited to the specific revisions proposed in Amendment No. 10 to CoC 
No. 1014. The NRC is addressing the commenter's concern, however, for 
educational and clarification purposes.
    The NRC addressed a similar comment about the ability of HI-

[[Page 70008]]

STORM UMAX Canister Storage Systems to withstand seismic events during 
the CoC No. 1040 certification rulemaking. It should be noted that the 
certification provided by approval of the HI-STORM 100 Cask System does 
not, in and of itself, authorize the use of this system at any specific 
site. Under 10 CFR 72.212(b)(5), before applying the changes authorized 
by an amended CoC and loading a cask, a general licensee wishing to use 
this cask system must perform written evaluations in accordance with 10 
CFR 72.212 to establish, among other things, that:
     Cask storage pads and areas have been designed to 
adequately support the static and dynamic loads of the stored casks, 
considering potential amplification of earthquakes through soil-
structure interaction, and soil liquefaction potential or other soil 
instability due to vibratory ground motion; and
     The independent spent fuel storage installation at the 
reactor site where the casks will be located will meet the requirements 
of 10 CFR 72.104 to ensure that radiation doses beyond the reactor's 
controlled area do not exceed 0.25 mSv (25 mrem) to the whole body, 
0.75 mSv (75 mrem) to the thyroid, and 0.25 mSv (25 mrem) to any other 
critical organ, and are further controlled to a level as low as is 
reasonably achievable.
    The seismic design levels of the HI-STORM 100 Cask System CoC are 
acceptable for most areas in the continental United States. For 
locations with potential for seismic activity beyond those analyzed for 
this system, additional NRC evaluations and certifications may be 
required before the system may be used in those locations.
    Similarly, although the design levels of the HI-STORM 100 Cask 
System CoC for flooding are also acceptable for most areas in the 
continental United States--again depending on site-specific analyses--
the NRC staff previously evaluated the impacts of flooding during the 
review of the initial certification for the HI-STORM Flood/Wind (FW) 
System. In its March 28, 2011, SER for the initial certification of the 
HI-STORM FW MPC Storage System (see Sections 4.8.2 and 7.3.1 of ADAMS 
Accession No. ML103020151), the NRC staff considered both full and 
partial flooding for both the vertical and horizontal positions for the 
MPC. The NRC staff found that the fully flooded condition would produce 
the highest reactivity in the spent fuel, and that the fully flooded 
model for safety evaluations ``is acceptable and applicable to all of 
the assembly configurations that are to be stored in the HI-STORM FW 
MPC Storage system,'' including damaged fuel configurations. In its 
March 28, 2011, SER, the NRC staff also noted the system's design 
measures to limit the rise in fuel cladding temperature under the most 
adverse flood event (one with a water level just high enough to block 
the MPC overpack's air convection inlet duct). The changes requested in 
Amendment No. 10 to CoC No. 1014 do not affect the NRC's prior flooding 
evaluation for the initial certification of this system.
    In addition, under 10 CFR 72.212(b)(6), before using the general 
license, the reactor licensee must review the Safety Analysis Report 
(SAR) referenced in the CoC or amended CoC and the NRC's SER evaluating 
the SAR to determine whether the reactor site parameters, including 
analyses of earthquake intensity, tornado missiles, and flooding, are 
enveloped by the cask design bases considered in these reports. Like 
those for seismic activity, the flooding and tornado missile design 
levels of the HI-STORM 100 Cask System CoC are acceptable for most 
areas in the continental United States. For locations with potential 
for flooding or tornado activity beyond those analyzed for this system, 
additional NRC evaluations and certifications may be required before 
the system may be used in those locations.
    Therefore, the ability of a particular cask system to protect 
additional spent fuel types against postulated natural disasters is 
required to be subject to rigorous analyses, both generic and site-
specific, before the fuel can be loaded at any given site. If the 
design basis of the HI-STORM 100 Cask System CoC No. 1014, Amendment 
No. 10, cannot be shown to envelop a particular site's parameters, 
Holtec or another vendor would need to obtain NRC certification for 
another system meeting the design specifications of the subject spent 
fuel before it could be loaded for dry storage.
    The NRC made no changes to the rule as a result of this comment.
    Comment 13: One commenter suggested that the NRC was in collusion 
with the licensee and cited an email exchange between the licensee and 
a member of the NRC staff as evidence of such collusion.
    NRC Response: The NRC disagrees with the comment. In its capacity 
as a regulator, the NRC regularly engages in discussions with licensees 
and applicants to facilitate a mutual understanding of the need for any 
licensing action, as well as the scope and intent of the licensing 
action. The NRC strives to make as much information as possible, 
including these interactions, publicly available whenever possible 
except where legal obligations dictate otherwise, such as for 
proprietary or security-related sensitive information. (see NRC 
Management Directive 3.4, ``Release of Information to the Public'' 
(ADAMS Accession No. ML080310417)). The email exchange cited by the 
commenter, which is a publicly available document in ADAMS, is one such 
example of this type of discussion. The NRC grounds its licensing 
actions on thorough and documented reviews of technical documents that 
enable the NRC to reach findings that public health and safety, as well 
as the common defense and security, will be adequately protected.
    The NRC made no changes to the rule as a result of this comment.
    Comment 14: One commenter objected to the use of a newer American 
Society of Mechanical Engineers (ASME) code standard for the manganese 
content in a carbon steel alloy used in some components of the cask 
system and one commenter asserted that at the 1.5 percent manganese 
content in the proposed standard, the steel becomes brittle. 
Furthermore, the commenter contended, these standards are not specific 
to the nuclear industry, and cannot compensate for poor design. 
Therefore, the alloy formula must be tested and specific for this 
particular design and nuclear spent fuel use.
    NRC Response: The NRC disagrees with these comments, and has 
provided its detailed assessment in the preliminary SER for Amendment 
No. 10 to CoC No. 1014 (ADAMS Accession No. ML15331A309). The minor 
change in manganese and carbon content of the proposed alloy has been 
endorsed by the ASME. This endorsement provides a high level of 
confidence in the quality and safety of the material for nuclear as 
well as non-nuclear applications. Any change in an ASME standard must 
be documented by rigorous testing under carefully controlled 
conditions. Based on this extensive and peer-reviewed testing, the fact 
that there is no change to the properties used in the original 
technical basis for the HI-STORM 100 Cask System CoC, and the fact that 
none of the safety analyses for this CoC are affected by the minor 
change in manganese content, the NRC believes that further testing for 
this specific application is unnecessary.
    The proposed increase in manganese content from 1.2 percent to 1.5 
percent maintains, if not improves, the toughness properties of the SA-
516 Grade 70 steel used in the HI-STORM 100 Cask System overpack. The 
NRC's preliminary SER for Amendment No. 10 to CoC No. 1014 analyzed 
this proposed

[[Page 70009]]

amendment and related Holtec documents and found that there is no 
change to the material strength, material density, or thermal 
properties of the SA-516 alloy steel, as indicated in the ASME 2007 and 
2010 codes. In order to use the alloy approved in the updated 2007-2010 
ASME codes, Holtec was required to request an amendment to use these 
codes for this alloy because the original HI-STORM 100 Cask System CoC 
references only the 1995-1997 ASME codes.
    The NRC made no changes to the rule as a result of this comment.
    Comment 15: A commenter stated that concrete temperature should be 
properly measured on a continuous basis. The same commenter also stated 
that each cask should be tested due to possible defects or damage 
during loading, as well as differences in the types and ages of spent 
fuel. Because conditions change over time, monitoring should be 
constant.
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The NRC agrees that concrete 
temperatures are important and should be properly measured, but 
disagrees that continuous measurement of these temperatures and 
constant monitoring are needed. Continuous measurement and constant 
monitoring of temperatures are unnecessary in an operating environment 
of very gradual temperature changes. Revision 1 of NUREG-1536, 
``Standard Review Plan for Spent Fuel Dry Storage Systems at a General 
License Facility'' (ADAMS Accession No. ML101040620), notes that for 
storage systems with internal air flow passages, the NRC has accepted 
periodic visual inspection of vents coupled with temperature 
measurements to verify proper thermal performance and detect flow 
blockages. The inspections are to take place within an interval that 
will allow sufficient time for corrective actions to be taken before 
the limiting accident temperature for spent fuel cladding is reached. 
The inspection interval should be more frequent than the time interval 
required for the fuel to heat up to the established accident 
temperature criteria, assuming a total blockage of all inlets and 
outlets.
    The NRC made no changes to the rule as a result of this comment.
    Comment 16: A commenter contended that all airflow and temperature 
measurements should be made ``constantly . . . not one time only,'' and 
performed ``on intake and output and within the annulus and with an up 
to date measurement device and not an antiquated anemometer.''
    NRC Response: The NRC disagrees with these comments. The NRC 
evaluated the proposed conditions for airflow and temperature 
measurements in its final SER (ADAMS Accession No. ML003711865) for the 
initial issuance of CoC No. 1014 in 2000, and did not find that 
constant temperature measurements were necessary. That SER noted that 
in addition to the mandatory initial air temperature rise test when the 
system is first placed in service, the overpack air inlet and outlet 
vents would be periodically surveyed or an optional overpack air 
temperature program would be implemented to verify continued 
operability of the heat removal system. Operating experience with this 
cask system since that time has given the NRC no reason to change its 
initial position on the need for constant temperature measurement.
    Concerning the commenter's statement about the need for an up-to-
date measurement device, the NRC has not specifically required the use 
of hot-wire anemometer or any other airflow measurement technology. The 
applicant may propose the use of any technology it believes will 
measure airflow with sufficient accuracy and reliability. The NRC is 
not aware of any basis to prohibit the use of hot-wire anemometer 
technology for measuring airflow or temperature.
    The NRC made no changes to the rule as a result of these comments.
    Comment 17: The same commenter that provided Comment 16 objected 
that Holtec and the NRC did not provide adequate information on ``other 
topics,'' and that this must be presumed to diminish the safety of the 
``flimsy'' Holtec cask system.
    NRC Response: The commenter did not specify any grounds for 
pronouncing the HI-STORM 100 Cask System flimsy, or any ``other 
topics'' for which additional information might be considered adequate.
    The NRC made no changes to the rule as a result of this comment.
    Comment 18: A commenter contended that ``measurements are not 
supposed to validate methods outside of experiments testing theory,'' 
and that the requirement to ``demonstrate'' an airflow model with 
measurements implies ``fraudulent'' intent to ``play with numbers to 
get what [NRC] and/or Holtec want'' to show the safety of the storage 
cask system.
    NRC Response: These comments are not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The NRC also disagrees with these 
comments. The NRC does not require measurements to validate methods 
that cannot be tested experimentally. The commenter particularly 
disapproved of a draft NRC requirement in an email to Holtec (ADAMS 
Accession No. ML15327A043) in which users of the HI-STORM 100 Cask 
System would be required to perform a ``thermal validation test'' to 
measure the total air mass flow rate through the cask system using 
direct measurements of air velocity in the inlet vents. The user would 
then be required to do an analysis of the cask system with these 
measurements ``to demonstrate that the measurements validate the 
analytic methods'' described in Chapter 4 of Holtec's Final Safety 
Analysis Report (ADAMS Accession No. ML14086A412), supporting its 
application for CoC No. 1014. The NRC has reason to require a licensee 
to demonstrate that an analytic method for thermal modeling of airflow 
through a cask is supported by real-world measurements. In making this 
demonstration, a licensee could ``play with numbers'' if it were 
allowed to measure anywhere it chose, but that is not the case here. 
The licensee is required to take measurements at NRC-specified 
locations.
    The NRC made no changes to the rule as a result of these comments.
    Comment 19: Citing NRC regulations at 10 CFR 72.236, ``Specific 
requirements for spent fuel storage cask approval and fabrication,'' 
one commenter alleged that Holtec violated U.S. law because ``the only 
protection from lethal radiation leaks is the \1/2\ inch MPC, whereas 
`The spent fuel storage cask must be designed to provide redundant 
sealing of confinement systems.' ''
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The NRC also disagrees with this 
comment. The MPC does provide protection from radiation leaks, but it 
is not the only protective barrier. Radiation shielding is also 
provided by the HI-STORM 100 Cask System overpack that is composed of 
inner and outer steel shells with the annulus between them filled with 
concrete, which is the primary radiation shielding material. If the 
commenter was referring only to leakage of radioactive materials from 
the MPC, however, Section 7.1 of the SER (ADAMS Accession No. 
ML003711865) for the HI-STORM 100 Cask System confirms the presence of 
redundant sealing of confinement systems in the canister's design:

[[Page 70010]]

    The [MPC] confinement boundary includes the MPC shell, the bottom 
baseplate, the MPC lid (including the vent and drain port cover 
plates), the MPC closure ring, and the associated welds. . . . The MPC 
lid (with the vent and drain port cover plates welded to the lid) and 
closure ring are welded to the upper part of the MPC shell at the 
loading site. This provides redundant sealing of the confinement 
boundary. . . . The redundant closures of the MPC satisfy the 
requirements of 10 CFR 72.236(e) for redundant sealing of confinement 
systems.
    The MPC's confinement design has multiple related purposes. The 
confinement design ensures that potentially contaminated air is 
contained within the MPC and that the MPC remains filled with helium 
coolant, so that the MPC can fulfill a third purpose: to keep outside 
air from contacting the spent nuclear fuel for the licensed life of the 
system.
    In addition to the redundant barriers to airborne radiation leakage 
in the design of the HI-STORM 100 MPC and cask system, there are 
procedural requirements to ensure that the system and its components 
function in operation as designed. In accordance with the CoC itself 
(ADAMS Accession No. ML15331A307), the design, purchase, fabrication, 
assembly, inspection, testing, operation, maintenance, repair, and 
modification of all structures, systems, and components that are 
important to safety, both for the MPC and the system as a whole, must 
be conducted in accordance with a Commission-approved quality assurance 
program that satisfies the applicable requirements of 10 CFR part 72, 
subpart G.
    The CoC also requires that when the MPC shell is welded to its 
baseplate, the fabricator must perform a helium leak test of the MPC 
weld's confinement using a helium mass spectrometer. This weld leakage 
test must include the base metals of the MPC shell and baseplate. 
Another helium leak test must be performed on the base metal of the 
fabricated MPC lid. Then, in the field, a helium leak test must be 
performed on the vent and drain port confinement welds and cover plate 
base metal before the loaded MPC can be emplaced within the concrete 
overpack. All MPC confinement boundary leakage rate tests must be 
performed in accordance with ANSI N14.5 to ``leaktight'' criteria. If 
the user detects a leakage rate exceeding the acceptance criteria, the 
user must determine the area of leakage and repair it to meet ASME Code 
Section III, Subsection NB requirements. The affected area must then be 
re-tested until the leakage rate acceptance criterion is met.
    The NRC made no changes to the rule as a result of this comment.
    Comment 20: Citing NRC regulations at 10 CFR 72.236, ``Specific 
requirements for spent fuel storage cask approval and fabrication,'' a 
commenter asserted that Holtec violated U.S. law also because its 
storage cask is not designed to provide adequate heat removal capacity 
without active cooling systems, and ``[t]he refusal to properly test 
[the cask's heat removal capacity] appears intentional to avoid knowing 
if it properly removes heat.''
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. The comment also does not explain how 
Holtec storage casks are not designed to meet the 10 CFR 72.236 
requirement to provide adequate heat removal capacity without active 
cooling systems. HI-STORM 100 Cask Systems have been deployed at 
independent spent fuel storage installations for more than a decade 
without active cooling systems.
    The NRC disagrees with the comment. The NRC's preliminary SER 
evaluated Holtec's supporting thermal analysis for Amendment No. 10 to 
CoC No. 1014 and found that the HI-STORM 100 Cask System certification 
``continues to be designed with a heat-removal capability having 
verifiability and reliability consistent with its importance to 
safety.'' The SER also found that spent fuel cladding continues to be 
protected against thermal degradation leading to gross ruptures, and 
other cask component temperatures continue to be maintained below the 
allowable limits for the accidents evaluated.
    There has been no refusal to test the cask system's heat removal 
capacity. The CoC language has been revised to require CoC No. 1014, 
Amendment No. 10, users to submit thermal validation test and analysis 
results in a letter report to the NRC within 180 days of either the 
user's loading of the first cask or undertaking the first spent fuel 
transfer operation with a cask fabricated to Amendment No. 10 
specifications. The revised condition also states, however, that for 
casks of the same system type, users may document in their 10 CFR 
72.212 report a previously performed test and analysis that has 
demonstrated adequate validation of the analytic thermal methods. The 
NRC will evaluate whether this previous test and analysis continues to 
demonstrate adequate validation of thermal analysis methods in light of 
the uncertainty of airflow measurements at the previously-specified 
locations.
    The NRC made no changes to the rule as a result of this comment.
    Comment 21: One commenter stated that the NRC has violated the 
Plain Writing Act of 2010 by failing to make the topics associated with 
this rulemaking clear, and failing to ``attach . . . the relevant 
documents in an orderly, clear manner.''
    NRC Response: The NRC disagrees with these comments. The topics 
associated with this rulemaking must necessarily address the CoC 
amendments requested by the applicant, and these are by nature highly 
technical. The March 14, 2016 (81 FR 13265), Federal Register notice of 
the direct final rule does, however, seek to explain in language as 
non-technical as possible the practical effects of the amendment 
requests for the use of the Holtec HI-STORM 100 Cask System under 
Amendment No. 10 of CoC No. 1014. In general, the NRC strives to write 
agency documents in a clear, concise, well-organized manner that also 
follows other best practices appropriate to the subject and the 
intended audience.
    As to the comment that documents relevant to this rulemaking were 
not ``attached . . . in an orderly, clear manner,'' the NRC followed 
its normal process of providing the ADAMS accession numbers to 
referenced documents so that interested persons may obtain access to 
the documents. If the commenter was referring instead to the table of 
references provided in the Federal Register notice for the direct final 
rule, the NRC also disagrees that the relevant documents were not 
presented in an orderly, clear manner. The order of the references 
starts with the applicant's amendment request, moves to the proposed 
revised CoC and TS documents supporting it, and concludes with the 
NRC's response to these submittals in the form of its SER on the 
proposed revisions.
    The NRC made no changes to the rule as a result of these comments.
    Comment 22: One commenter stated that the percentage of the NRC's 
budget that must be recovered should be recovered in fines and not 
fees.
    NRC Response: The comment is not within the scope of this 
rulemaking, which is limited to the specific revisions proposed in 
Amendment No. 10 to CoC No. 1014. Under the Omnibus Budget 
Reconciliation Act of 1990, as amended, the NRC is required by law to 
recover 90 percent of its budget through fees for licensing and other 
actions. Therefore, any change in this requirement can only be achieved 
by an act of Congress.

[[Page 70011]]

    The NRC made no changes to the rule as a result of this comment.
    In summary, the NRC did not receive any comments that warranted 
withdrawal of the direct final rule. Therefore, none of these comments 
required a change in the rule's effective date of May 31, 2016.

    Dated at Rockville, Maryland, this 28th day of September, 2016

    For the Nuclear Regulatory Commission.
Michael R. Johnson,
Acting Executive Director for Operations.
[FR Doc. 2016-24466 Filed 10-7-16; 8:45 am]
 BILLING CODE 7590-01-P