As copied below NRC had a meeting to discuss draft documents related to the performance of nuclear reactor cores under accident conditions. ML14128A076 Inverso
May 13, 2014
SUBJECT: SUMMARY OF THE APRIL 29-30, 2014, PUBLIC MEETING ON
THE 10 CFR 50.46C PROPOSED RULE AND DRAFT
REGULATORY GUIDANCE (TAC NO. ME2908)
The U.S. Nuclear Regulatory Commission (NRC) held a two-day Category 3 public meeting on
April 29-30, 2014, to discuss the Title 10 of the Code of Federal Regulations (10 CFR) Section
50.46c proposed rule and associated draft regulatory guidance.
Following is from the last paragraph of the report of the two day meeting:
The attendees noted that the following topics should be the subject of future public meetings:
• Risk-informed alternative: Alternative detailed discussion including proposed
approaches
by non-pilot entities that may differ from the pilot approach (e.g.,
addressing long-term core cooling only for in-vessel effects) (1 full
day in June)
• Open items needing resolution before implementation: Implementation/compliance
requirements, long-term cooling interaction (and the need to develop an additional draft
regulatory guide on this topic), hydrogen pick up models (1 full day in June)
• Breakaway oxidation (including reporting requirements for breakaway
oxidation)/DG1261,1262,1263 (1.5 full days in June)
• Corrective action/reporting (1 full day in June
Without going into details, my forecast is that the above future meetings will not take place. Now, if the meetings indeed do take place, I'll admit the error of my forecast and at that time I'll disclose the basis of the erroneous forecast.
Following is the NRC's version of the two day meeting.
May 13, 2014
MEMORANDUM TO: Sher Bahadur, Deputy Director
Division of Policy and Rulemaking
Office of Nuclear Reactor Regulation
FROM: Tara Inverso, Project Manager /RA/
Rulemaking Branch
Division of Policy and Rulemaking
Office of Nuclear Reactor Regulation
SUBJECT: SUMMARY OF THE APRIL 29-30, 2014, PUBLIC MEETING ON
THE 10 CFR 50.46C PROPOSED RULE AND DRAFT
REGULATORY GUIDANCE (TAC NO. ME2908)
The U.S. Nuclear Regulatory Commission (NRC) held a two-day Category 3 public meeting on
April 29-30, 2014, to discuss the Title 10 of the Code of Federal Regulations (10 CFR) Section
50.46c proposed rule and associated draft regulatory guidance. The meeting was held at the
NRC headquarters location in Rockville, Maryland. The purpose of the meeting was to discuss
several items related to the proposed rule and draft regulatory guidance to enhance
understanding and to aid in the development of public comments. The NRC did not accept
formal written comments during the meeting. On Day 1, the meeting was attended by 69
individuals primarily representing fuel vendors, utilities, private citizens, and NRC staff, 17 of
who participated through audio teleconferencing and webinar. On Day 2, 49 individuals
attended the meeting, including 15 through audio teleconferencing and webinar.
The meeting slides and handouts are available in the Agencywide Document Access and
Management System (ADAMS) under Accession Nos. ML14114A498 (NRC Slides),
ML14114A499 (NRC Slides), ML14120A017 (Industry Slides), ML14120A009 (Industry Slides),
ML14120A011 (Industry Slides), ML14120A012 (Industry Slides), ML14120A010 (Industry
Slides), ML14120A015 (Industry Slides), ML14120A018 (Industry Slides).
CONTACT: Tara Inverso, NRR/DPR
301-415-1024
S. Bahadur - 2 -
In addition to the material presented in the slides, the major areas of discussion are summarized
as follows:
Proposed Rule Background:
• A member of the public requested that the NRC differentiate between deterministic
versus probabilistic treatment within the rule. The NRC staff explained that the effects of
debris during the long-term is the only portion of the rule that can be addressed using a
probabilistic risk assessment method.
• A representative of the Nuclear Energy Institute requested that the NRC address public
comments using a resolution matrix.
• A member of the public asked whether the March 13-14, 2014, public meeting on fuel
fragmentation, relocation, dispersal was transcribed. The NRC staff explained that public
meetings are typically not transcribed, but that the meeting summary is available
(ADAMS Accession No. ML14100A131). The same member of the public mentioned
that there were many acronyms used during that meeting and she would like
clarification. The NRC staff committed to calling the individual to provide some clarity.
NRC Presentation on the Risk-Informed Alternative:
• The NRC staff noted that the draft guidance for the risk-informed alternative will be
published for comment once it is developed. The current schedule for publication is
March 2015.
• The NRC clarified that entities would be required to “characterize” defense-in-depth and
safety margins, not “quantify” them.
• A member of the public asked if there were other plants, in addition to South Texas
Project (STP), that were piloting the risk-informed alternative. Clarification of the NRC’s
previous response: Point Beach is risk-informing long-term core cooling for in-vessel
effects.
• A member of the public requested information on the calculations and models used to
predict risk.
• An industry representative questioned what “entity” meant in the risk-informed reporting
criteria rule language. The NRC replied that “entity” means combined license holder,
combined license applicant, etc. and that it was a catch-all term.
• An industry representative questioned why proposed 10 CFR 50.46c(c), “Relationship to
other NRC regulations,” only points to General Design Criterion (GDC)-35 and not
GDC-38 and GDC-41, even though there are rule language changes in those criteria.
The NRC omitted to answering this question (including the relationship between 10 CFR
50.46a, Appendix K and the GDCs) at a future public meeting.
• One member of the public questioned whether the Summer and Vogtle applicants are
using the risk-informed method. The NRC staff indicated that they are not. The same
member of the public asked whether the insulation materials used by Summer and
Vogtle can create debris. The NRC staff stated that the insulation may become debris
but that it is not problematic for sump operation.
• The NRC staff clarified that while the rule would require consideration of all operational
modes, licensees using the risk-informed approach would not necessarily need a
shutdown and low power PRA model. Consistent with Regulatory Guide 1.174, risk from
modes that are not modeled in the probabilistic risk assessment may be treated
qualitatively or with bounding techniques.
S. Bahadur - 3 -
Industry Presentations on the Risk-Informed Alternative:
• A member of the NRC staff asked whether the non-pilot plants plan to follow the same
method as STP. An industry representative explained that there may be some
differences in the scope of approach used by the non-pilots.
• An industry representative stated that absent 10 CFR 50.46c, up to 40 exemptions may
be required by the 14 units that have expressed intent to resolve GSI-191 in a
risk-informed manner.
NRC Overview of the Proposed Rule (Non-Risk-Informed Alternative Portion):
• An industry representative noted that industry’s preference is to NOT include plant
names in proposed 10 CFR 50.46c(o), “Implementation.” He noted that, as the
proposed rule language is currently written, additional rulemaking or exemptions would
be needed to update any changes in track assignments. Industry recommended further
discussions on this topic.
• A member of the public noted that there were many additional causes of embrittlement,
including contaminants, nitriding, and water hammer. An NRC representative responded
that he was confident that the NRC has considered the known causes of embrittlement
for zirconium clad fuel designs.
• Several industry representatives noted that additional public meetings were necessary to
discuss the long-term peak cladding temperature limit. Some also commented that
industry was not in favor of including a prescriptive analytical limit in the rule language.
• A member of the public noted that, now that the NRC is in a different stage of the
“nuclear renaissance,” the NRC should reconsider whether the implementation plan for
new reactors needs to be as complex as currently written in the proposed rule.
• On the topic of restructuring the Code of Federal Regulations, a member of the public
noted that there is already difficulty following the regulations. A restructure would add to
that difficulty. He further noted that Cathcart-Pawel vs. Baker-Just is a bigger concern
and referenced the work of Mr. Mark Leyse and Mr. Robert Leyse in this subject.
• On the Cumulative Effects of Regulation (CER), an industry representative noted that a
public meeting on CER and the Risk Prioritization Initiative was held on April 24, 2014.
A summary of that meeting is available in ADAMS under Accession No. ML14129A208.
• An industry representative noted that breakaway oxidation is the most onerous part of
complying with the proposed requirements, yet it is the limit that is least likely to be
exceeded. Industry proposed removing reload batch testing and reporting requirement
from the rule.
• Based on discussions concerning the applicability of the Baker-Just correlation, the
industry and public are still confused about the use of integral time-at-temperature
versus maximum local oxidation along with the use of the Cathcart-Pawel weight gain
correlation as a surrogate for cladding embrittlement (due to oxygen diffusion).
• A member of the public stated his concern that the NRC was ignoring petitions for
rulemaking (PRMs) related to the ECCS acceptance criteria. The NRC staff explained
that these PRMs (i.e., PRM-50-93/95) are being evaluated separately and stated that, to
date, four interim reports have been published by the NRC.
• A member of the public suggested that Mr. Mark Leyse should be invited to a follow-on
meeting, since Mr. Leyse is involved in many issues related to the ECCS acceptance
criteria.
• One member of the public questioned the meaning of the term “external stakeholders”
and asked whether she and her group are considered stakeholders and will have an
S. Bahadur - 4 -
opportunity to participate in decision-making. The NRC staff stated that the term
includes industry and the public.
• An industry representative recommended that 10 CFR 50.59 be allowed for use in
evaluating changes under the risk-informed alternative approach.
• An industry representative noted that some shutdown modes are based on
defense-in-depth and that numeric values could not be generated for lower modes. He
questioned whether the rule should clarify when the initiating events can occur.
Industry Presentation on the Proposed Rule (Non-Risk-Informed Alternative Portion):
• An industry representative noted that it would be beneficial to articulate the details of a
hypothetical implementation of the rule to identify any potential gaps.
• A member of the public noted that, while the industry is now requesting that the NRC
consider a graded approach (relative to the margin to the peak cladding temperature
limit) for reporting errors, the industry was not supportive of that approach during the
Advance Notice of Proposed Rulemaking stage. The industry noted that the industry
was supportive of the approach, but not the complex grading that the NRC suggested.
• An industry representative noted that guidance was needed to provide an acceptable
method for testing long-term peak cladding temperature.
• Based on discussions, an industry standard approach for defining long-term cladding
performance (and analytical limits) does not exist. This item could become a critical path
issue for the rulemaking.
NRC Presentation on Draft Regulatory Guides (DGs) 1261, 1262, and 1263:
• An industry representative noted that all heating processes should be acceptable in the
test procedures.
• An industry representative noted the desire to reduce the number of required tests.
• A member of the NRC staff suggested that the staff may consider removing the need for
periodic testing for breakway oxidation from the rule and including it in the DG.
• Several members of the industry requested that the NRC consider whether it is
acceptable for the industry to verify acceptable cladding performance with respect to
breakaway oxidation within the quality assurance program.
• A member of the public asked whether the NRC is investigating high-burnup fuel with
respect to breakaway oxidation. The NRC clarified that the test procedures are based
on as-received materials. Thus, if as-received materials experience breakaway
oxidation, it is expected that high-burnup fuel would also experience the same
phenomenon at the conditions identified in as-received materials.
• An industry representative asked for clarification on:
o Water quality requirements in the test procedure
o Limitation on maximum steam flow
o The use of weight gain correlations
• An industry representative requested additional information on the qualification of
hydrogen pick-up models. The NRC committed to further discussion on this topic.
• The NRC noted that many aspects of the draft regulatory guides will be discussed
further in future public meetings.
S. Bahadur - 5 -
Industry Presentation on Draft Regulatory Guides (DGs) 1261, 1262, and 1263:
• An industry representative noted that the ductile-to-brittle transition is overly
conservative and could be relaxed. However, he noted that the industry still supports
the preservation of ductility as the basis for the rulemaking.
Topics for Future Public Meetings:
The attendees noted that the following topics should be the subject of future public meetings:
• Risk-informed alternative: Alternative detailed discussion including proposed
approaches by non-pilot entities that may differ from the pilot approach (e.g., addressing
long-term core cooling only for in-vessel effects) (1 full day in June)
• Open items needing resolution before implementation: Implementation/compliance
requirements, long-term cooling interaction (and the need to develop an additional draft
regulatory guide on this topic), hydrogen pick up models (1 full day in June)
• Breakaway oxidation (including reporting requirements for breakaway
oxidation)/DG1261,1262,1263 (1.5 full days in June)
• Corrective action/reporting (1 full day in June)
Enclosure:
List of Attendees
S. Bahadur - 5 -
Industry Presentation on Draft Regulatory Guides (DGs) 1261, 1262, and 1263:
• An industry representative noted that the ductile-to-brittle transition is overly
conservative and could be relaxed. However, he noted that the industry still supports
the preservation of ductility as the basis for the rulemaking.
Topics for Future Public Meetings:
The attendees noted that the following topics should be the subject of future public meetings:
• Risk-informed alternative: Alternative detailed discussion including proposed
approaches by non-pilot entities that may differ from the pilot approach (e.g., addressing long-term core cooling only for in-vessel effects) (1 full day in June)
• Open items needing resolution before implementation: Implementation/compliance
requirements, long-term cooling interaction (and the need to develop an additional draft
regulatory guide on this topic), hydrogen pick up models (1 full day in June)
• Breakaway oxidation (including reporting requirements for breakaway
oxidation)/DG1261,1262,1263 (1.5 full days in June)
• Corrective action/reporting (1 full day in June)
Enclosure:
List of Attendees
DISTRIBUTION:
PUBLIC RidsOgcMailCenter RidsNrrDpr MMahoney, NRR PClifford, NRR
TInverso, NRR GLappert, NRR RidsNroOd RidsResOd TBoyce, RES
ADAMS Accession Nos.:
Pkg.: ML14114A501
Notice ML14083A615
Summary ML14128A076
NRC Presentations ML14114A498, ML14114A499
Industry Presentations ML14120A017, ML14120A009, ML14120A011, ML14120A012, ML14120A010,
, ML14120A018
NRC-001
OFFICE DPR/PRMB/PM DPR/PRMB/RS DPR/DD DPR/PRMB/PM
NAME TInverso GLappert SBahadur TInverso
DATE 5/8/2014 5/13/2014 5/13/2014 5/13/2014
OFFICIAL RECORD COPY
ENCLOSURE
LIST OF MEETING ATTENDEES (Day 1 - April 29, 2014)
Name Organization
Dave Medek APS
Steven Smiley STP
Tara Inverso NRC
Alysia Bone NRC
David Mitchell WEC
Chris Brown NRC
Phil Sharpe GEH
Kurshad Muftuoglu GEH
Gregg Swindlehurst GSN
Chris Hoffman PPL
Paul Leonard Industry
Yang-Pi Lin GNF/GEH
Charles Albury STP
Gregory J. Hill AEP
Erik Mader EPRI
Tom Eichenberg TVA
Mo Dingler WCNOC
Bert Dunn AREVA
Lisa Gerken AREVA
Ron Holloway WCNOC
Charles Ader NRC
Kurt Flaig PWROG
Kevin McCoy AREVA
Beth Wetzel TVA
Steve Blossom STP
Wayne Harrison STP
Pablo Garcia Iberdrola
Roger L. Thomas, Jr Duke Energy
Andy Olson Exelon
Al Strasser Aquarius
Don Williamson SCEG
Ken Yueh EPRI
Alan Meginnis AREVA
Robert Florian SNC
Jana Bergman Curtiss-Wright Scientech
Ralph Landry Private Citizen
Gordon Clefton NEI
Mitch Nissley Westinghouse
David Boirel NRC
Yun Ho Kim KHNP
Kanghoon Kim KEPCO
HoYoung Park KEPCO
JuHyun Park KEPCO
Jaehoon Jeong KEPCO
- 2 -
Name Organization
Mark Richter NEI
Nasser Nik Entergy
Steve Smith NRC
Stewart Bailey NRC
Harold Scott NRC
Paul Klein NRC
Robert Beall NRC
Michelle Flanagan NRC
Jodi Rappe Nuscale Power
Mark Handrick Duke Energy
Marvin Lewis Private Citizen
Ruth Thomas Private Citizen
Roger Andreasen Ameren
Tom Remick APS
Gilbert Zigler Enercon
Jim Smith Westinghouse
Kathleen Parish APS
Ken Frederick FENOC
Bob Leyse Private Citizen
Heinz-Gunther
Sonnenberg
GRS
Dana Knee Dominion
Ryan Sprengel Mitsubishi
Patricia Quaglia Westinghouse (Sweden)
Gretel Johnston BEST/MATRR
John Alvis Anatech
- 3 -
LIST OF MEETING ATTENDEES (Day 2 - April 30, 2014)
Name Organization
Kurt Flaig PWROG
David Mitchell WEC
Steven Smiley STP
Beth Wetzel TVA
Chris Brown NRC
Tara Inverso NRC
Dave Medek APS
Kurshad Muftuoglu GEH
Gordon Clefton NEI
Alysia Bone NRC
Yang Pi Lin GNF/GEH
Charlie Albury STP
Phil Sharpe GEH
Lisa Gerken AREVA
Pablo Garcia Iberdrola
Erik Mader EPRI
Kevin McCoy AREVA
Don Williamson SCEG
Alan Meginnis AREVA
Tom Eichenberg TVA
Robert Florian SNC
Roger L. Thomas, Jr. Duke
Gregg Swindlehurst GSN
Nasser Nik Entergy
Al Strasser Aquarius
Gregory J. Hill AEP
Ralph Landry Private Citizen
Ken Yueh EPRI
Andy Olson Exelon
Yun Ho Kim KHNP
David Boirel NRC
Mitch Nissley Westinghouse
Harold Scott NRC
Jeremy Dean NRC
Jodi Rappe Nuscale Power
Mark Handrick Duke Energy
Marvin Lewis Private Citizen
Tom Remick APS
Gilbert Zigler Enercon
Jim Smith Westinghouse
Kathleen Parish APS
Ken Frederick FENOC
Bob Leyse Private Citizen
- 4 -
Name Organization
Heinz-Gunther
Sonnenberg
GRS
Dana Knee Dominion
Ryan Sprengel Mitsubishi
Patricia Quaglia Westinghouse (Sweden)
Gretel Johnston BEST/MATRR
John Alvis Anatech
And, here are the slides, portrait, not landscape.
ML14114A498 (NRC Slides), ML14114A499 (NRC Slides),
ML14120A017 (Industry Slides), ML14120A009 (Industry Slides), ML14120A011
(Industry Slides), ML14120A012 (Industry Slides), ML14120A010 (Industry
Slides), ML14120A015 (Industry Slides), ML14120A018 (Industry Slides)
Following three slides are from ML14120A012
Slide 1
10 CFR 50.46c Rulemaking
Industry Preparations
Tom Eichenberg
REG-TAC Chairman
NRC Public Meeting
April 29-30, 2014
Slide 3
FRN Question 1
Performance-Based Peak Cladding Temperature Limit
• Stated Goal - protect against loss of coolable geometry
– Brittle Failure Upon Quench
– High Temperature Ductile Failure
– Autocatalytic oxidation
• SRM Directive - achieve performance based ECCS – ML030910476, March 3, 2003.
– Prescriptive limit(s) inconsistent with the performance based directive
– 2200F
• “...provide a substantial degree of conservatism…” - FRN Volume 39 #3, January 4, 1974, pg 1002
© 2014 Electric Power Research Institute, Inc. All rights reserved. 3
Slide 4
FRN Question 1 (continued)
Performance-Based Peak Cladding Temperature Limit
• Current test methodology may be adequate to higher
temperatures
– Industry coordinated LOCA round robin showed no catalytic oxidation using wide range of steam flows
• Vendor LOCA evaluation models already consider
exothermic heat generation
– “Autocatalytic” phenomenon is an energy balance issue
• Reaction energy release versus heat transfer to steam
• Science is well understood and no new test required
• Additional material data may be needed for high (>2200F)
temperature ductile failure issues
© 2014 Electric Power Research Institute, Inc. All rights reserved. 4
