ML112580385
| ML112580385 | |
| Person / Time | |
|---|---|
| Issue date: | 09/22/2011 |
| From: | Vonna Ordaz NRC/NMSS/SFST |
| To: | Mccullum R Nuclear Energy Institute |
| Piotter J, NMMS/SFST (301) 492-3286 | |
| References | |
| Download: ML112580385 (5) | |
Text
September 22, 2011 Mr. Rod McCullum Nuclear Energy Institute 1776 I Street, N.W., Suite 400 Washington D.C. 20006-3708
SUBJECT:
NRC RESPONSE TO NEI WHITE PAPER ON CONTENTS DEFINITION FOR SPENT FUEL CASKS AND TRANSPORTATION PACKAGES
Dear Mr. McCullum:
This letter responds to the Nuclear Energy Institutes (NEI) letter dated November 9, 2010, enclosing NEIs, Industry White Paper on Storage Cask/Transportation Package Contents (White Paper). NEI submitted the White Paper to the NRCs Division of Spent Fuel Storage and Transportation (SFST) as a step towards resolution of a pilot issue under NEIs Regulatory Issues Resolution Protocol (RIRP). The pilot issue introduced by NEI addresses the question of whether certain additional structural modifications to fuel assemblies installed to mitigate PWR Fuel Top Nozzle Stress Corrosion Cracking must be identified and addressed as storage cask contents consistent with the requirements of 10 CFR Part 71and 10 CFR Part 72. NEIs White Paper states that Guide Tube Anchors, Instrument Tube Tie Rods (ITTRs) and other similar devices are not by definition contents of a spent fuel storage cask. The White Paper also states that these components are not by definition licensed material for shipment in a spent fuel package. Therefore, NEIs White Paper concludes that this hardware does not require a Part 71 CoC approval to be stored or transported in designs with a CoC license approval, a Part 72 license approval, or a Certificate of Compliance (CoC) storage approval.
The NRC staff does not agree with NEIs conclusion. The staff has determined that Guide Tube Anchors, ITTRs, and similar devices are contents because they constitute the overall physical structure of a fuel assembly, which are considered the spent nuclear fuel contents of a spent fuel storage cask or package. The regulations for storage and transportation of spent nuclear fuel provide requirements for the cask, package, packaging, or contents. There are no regulatory definitions or exceptions that would allow for the classification and special treatment of this supplemental hardware outside of that required for spent nuclear fuel contents.
Therefore, the NRC does not endorse NEIs conclusion that supplemental hardware such as Guide Tube Anchors, ITTRs, and similar devices does not require a Part 71 CoC approval to be stored or transported in designs with a CoC license approval, a Part 72 license approval, or a Certificate of Compliance (CoC) storage approval. Accordingly, without additional NRC approval, any supplemental hardware that does not fall within the bounds of the approved contents specified in the CoC, is not authorized unless a licensee seeks a license or CoC amendment in accordance with the applicable regulations.
However, NEI may wish to consider whether hardware such as ITTRs or Guide Tube Anchors could be considered as a basic constituent of spent fuel assembly that is already encompassed by the specifications in the associated CoC. While recognizing that certificates and licensees have the change authority granted by 10 CFR 72.48, for the purposes of the RIRP pilot, NEI
should consider proposing examples and screening criteria that would enable supplemental hardware to be addressed in the storage SAR under the change authority of 10 CFR 72.48.
There is no change authority for users of a SNF package certified under Part 71, and supplemental hardware may pose unique challenges during transportation. Therefore, specification of this hardware is explicitly required for Part 71 certificates, and a CoC amendment is needed to allow the transportation of such hardware under 10 CFR Part 71.
The enclosure provides additional information regarding the basis for the NRCs response and suggested paths forward for industry to attempt generic resolution of the pilot issue for both storage casks and transportation packages. The staff suggests a public meeting to determine next steps in resolving the issue within the RIRP process. If you have any questions or comments, please contact Jason Piotter or Chris Staab of my staff at 301-492-3286 or 301-492-3321, respectively.
Sincerely,
/RA/
Vonna L. Ordaz, Director Division of Spent Fuel Storage and Transportation Office of Nuclear Material Safety and Safeguards
Enclosure:
Staff Response to NEI White Paper
should consider proposing examples and screening criteria that would enable supplemental hardware to be addressed in the storage SAR under the change authority of 10 CFR 72.48.
There is no change authority for users of a SNF package certified under Part 71, and supplemental hardware may pose unique challenges during transportation. Therefore, specification of this hardware is explicitly required for Part 71 certificates, and a CoC amendment is needed to allow the transportation of such hardware under 10 CFR Part 71.
The enclosure provides additional information regarding the basis for the NRCs response and suggested paths forward for industry to attempt generic resolution of the pilot issue for both storage casks and transportation packages. The staff suggests a public meeting to determine next steps in resolving the issue within the RIRP process. If you have any questions or comments, please contact Jason Piotter or Chris Staab of my staff at 301-492-3286 or 301-492-3321, respectively.
Sincerely,
/RA/
Vonna L. Ordaz, Director Division of Spent Fuel Storage and Transportation Office of Nuclear Material Safety and Safeguards
Enclosure:
Staff Response to NEI White Paper DISTRIBUTION: SFST r/f NMSS r/f BWhite, NMSS G:\\SFST\\Staab\\NEI\\Top Nozzle Response 2.doc ADAMS ML112580385 OFC:
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JPiotter CStaab EBenner MRahimi DPstrak MWaters DATE:
8/9/2011 8/10/2011 8/9/2011 8/9/2011 8/9/2011 8/9/2011 OFC:
MSampson DWeaver EBowdenBerry via e-mail VOrdaz DATE:
8/10/2011 8/10/2011 9/6/2011 9/22/2011 C = COVER E = COVER & ENCLOSURE N = NO COPY OFFICIAL RECORD COPY
Enclosure Staff Response to NEI White Paper Summary of Staff Position Guide Tube Anchors, ITTRs, and similar devices that constitute the hardware of a fuel assembly are contents of a dry storage cask or spent fuel package. The NRC reviews and approves the specific contents for each spent fuel storage site-specific license or cask CoC and explicitly specifies the approved contents that are authorized for storage or transportation. The regulations as a whole are intended to ensure the safe storage and transportation of spent fuel assemblies and associated components. Furthermore, the current regulatory framework treats material that is placed inside a storage cask or transportation package as an approved content of the cask or package. Any type of special nuclear material, radioactive material, and non-radioactive components or hardware that do not fall within the bounds of the approved contents specified in the site-specific license or cask CoC are not authorized. The licensee must seek a license or CoC amendment in accordance with the regulations to store or transport materials that are not specified.
Description of Spent Fuel Contents in License Documents Within the Part 71 CoC, approved contents are specified in the certificate, which is issued on the safety basis provided in the application submitted to the NRC. Within the Part 72 CoC, the contents are specified and the certificate is issued on the basis of the FSAR, which is generically referenced by the CoC. Spent fuel is specified as an approved content of dry storage casks and spent fuel transportation packages. Spent fuel contents are generally specified by a basic description of the spent fuel assembly (e.g., fuel type or lattice type),
important dimensions, and other limits regarding the physical and nuclear characteristics of the fuel assembly. Spent fuel contains several subcomponents and hardware that make up the basic physical structure of the spent fuel assembly lattice (e.g., fuel rods, control rod tubes, springs, grid straps, end caps, nozzles, etc. ). The spent fuel assembly contains various forms of irradiated special nuclear material within spent fuel pellet matrix, and may contain radioactive material on external cladding surfaces (e.g., crud).
NRC regulations do not explicitly define each subcomponent and physical characteristic of the spent fuel assembly. Nor are these subcomponents explicitly specified as allowable contents of dry storage casks and spent fuel transportation packages. The safety analyses for proposed SNF contents and designs do however consider and examine the types of SNF hardware and radioactive constituents (and potential variations that are commonly accepted) that are important to the performance and safety of the package.
Other specified approved contents may include irradiated or unirradiated components and hardware that are considered integral to the spent fuel assembly, but may also be separable from the basic physical structure of a spent fuel lattice (e.g., Burnable Poison Rod Assembly).
In some instances, these integral components are specifically defined and limited as allowable contents because they may significantly affect the performance of spent fuel lattice structure itself, the structure of the surrounding package during normal operations or accident conditions, or they may contribute to the reactivity or radiological consequences of the package system during operations. A key factor in this determination is whether the inclusion of such components significantly influences and subsequently changes the result of the safety analyses.
Therefore, additional description of these types of components integral to the spent fuel assembly, and associated nuclear and physical characteristics, are specifically evaluated in the safety analyses, and are specified in the CoC.
2 Furthermore, spent fuel may also not be in its original form as a result of failure (e.g., fuel debris) or post-irradiation repairs (e.g., reconstituted or repaired fuel). The special nature and form of this type of contents, and any required confinement structures (e.g., cans) are specified in the CoC. The definitions of damaged versus intact fuel are explicitly defined in most CoCs for purposes of understanding confinement and handling needs to assure ready-retrievabilty for storage as well as containment and criticality safety for transportation.
Potential Path Forward With respect to resolving the issue of regulatory approval of guide tube anchors, ITTRs, and similar devices within the RIRP-I-10-01, NEI may wish to address whether the hardware:
- 1)
Should be considered a variation of the basic constituency of a spent fuel assembly, or
- 2)
As an integral component that is separable, whether the associated physical parameters are significantly unique from other subcomponents of a typical fuel assembly and impact safety, and
- 3)
Whether further explicit specification as allowable spent fuel contents under Part 71 and Part 72 is necessary.
For storage, the addition of an ITTR or guide tube anchor appears to be an addition of a component to the structure of the spent fuel assembly, in a similar manner that a spent fuel assembly is repaired on a subcomponent level or reconstituted to ensure continued structural integrity of the assembly. Given precedent with recent approvals the impact of ITTRs appears to only potentially affect the future retrievability of spent fuel. A licensee or vendor may be able to specify the use of ITTRs in the FSAR, within the bounds of the approved content specifications in the CoC, under the change authority of 10 CFR 72.48. It may further be possible for industry to collectively demonstrate a bounding evaluation using 10 CFR 72.48 in order to generically resolve the pilot issue for storage. In this way, the collective industry could avoid duplicative work by individual vendors or licensees.
For transportation, the spent fuel configuration with additional hardware is not explicitly defined in the application, and there is no change authority granted to users under Part 71 to make such changes. The CoC, including reference to the specific application material, is the basis for determining whether such contents are allowed. Therefore, if Guide Tube Anchors, ITTRs or similar devices are not analyzed in the application and specified within the approved contents of the Part 71 certificate, such hardware is not allowed for shipment. The transportation amendment review for minor changes to allowable contents is relatively short for safety changes of minor significance. The staff has also identified the possibility that components such as ITTRs may change the stiffness of the spent fuel lattice structure, which may in turn impact the performance of the containment lid structure during Hypothetical Accident Conditions (HAC).
This issue would need to be addressed either generically or individually in order to receive transportation approval. A generic approach by industry could be submittal of a bounding analysis in the form of a topical report for which NRC could respond with a bounding Safety Evaluation Report. In this way, industry would only need to submit amendment requests referencing the bounding analysis. This generic approach would mitigate duplicative effort by individual vendors and licensees.