ML20309A977
| ML20309A977 | |
| Person / Time | |
|---|---|
| Site: | 07109377 |
| Issue date: | 11/03/2020 |
| From: | Pierre Saverot Storage and Transportation Licensing Branch |
| To: | Christopher Regan Division of Fuel Management |
| PSaverot - NMSS/DFM/STLB - 301.415.7505 | |
| Shared Package | |
| ML20309A976 | List: |
| References | |
| EPID L-2019-LRM-0029 | |
| Download: ML20309A977 (4) | |
Text
C. Regan UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 3, 2020 MEMORANDUM TO:
Christopher Regan, Deputy Director Division of Fuel Management, NMSS FROM:
Pierre Saverot, Project Manager
/RA/
Storage and Transportation Licensing Branch Division of Fuel Management, NMSS
SUBJECT:
SUMMARY
OF OCTOBER 13, 2020 MEETING WITH TN AMERICAS LLC
=
Background===
On December 13, 2016, July 30, 2019, and March 24, 2020, Category 1 public meetings were held between the U.S. Nuclear Regulatory Commission (NRC) staff and representatives from TN Americas LLC, Orano Federal Services, DOMINION ENERGY, and EPRI to discuss the licensing of the Model No. TN-32B HBU cask selected to support the DOE/EPRI high burnup cask research and development project. This fourth pre-application meeting, noticed on September 17, 2020 (ADAMS Accession No. ML20261H386), was held by videoconference.
The meeting attendance list and the presentation are provided as Enclosure Nos. 1 and 2, respectively.
Discussion The TN-32B HBU cask, loaded with 32 PWR high burn up (greater than 45 GWd/MTU) spent fuel assemblies, with four different cladding types, has been placed in storage in November 2017 under certificate of compliance (CoC) No. 72-1021.
NRC staffs inputs from the last two pre-application meetings, coupled with change requests from DOE and/or ORANO, led to some design changes from what was originally contemplated:
foam will no longer be used and the applicant is reverting to the redwood-balsa wood design of the TN-40 and TN-68 impact limiters; the spacer support bars and 1-inch thick lance cover plate have been redesigned; and the thermocouple lance assemblies are now installed through the lid.
The applicant explained that the lance cover plate is welded to the surface of lid with staggered fillet welds because it sits down in the recess space and cant move laterally; thus, a continuous weld is not needed. This also entails a reduction in associated operator dose during welding operations on this loaded cask. Since a fracture of the lance cover plate would be a problem for containment, staff asked why the applicant did not angle or tilt slightly the 6 puncture bar to obtain a full response on the closure lid: the applicant explained that (i) the center of gravity is
C. Regan 2
lined up with the puncture bar, (ii) the impact limiter has been ignored to show how well the cover plate resists, and (iii) the LS-DYNA model shows that there is no inelastic deformation on the containment boundary.
In order to facilitate the technical review, staff suggested that the application includes the following: a sketch of the modified closure lid; a detailed description, with corresponding figures, of the containment boundary, i.e., the lance assembly itself and not the lance cover plate which only needs staggered fillet welds; a sketch of the revised lance cover plate design (possibly similar to the photograph on slide 7); and a full explanation on the finding that there is no inelastic deformation in the containment boundary, including the lance assembly, main lid, and vent/drain port cover plates.
The thermal evaluation results show that no components exceed their respective temperature limits for worst-case normal conditions of transport (NCT) hot (100°F ambient) conditions, or during or following hypothetical accident conditions (HAC) fire event. However, it was noted that the maximum radial neutron resin temperature of 293°F, already a concern in the storage license application even with the cask in a vertical orientation, is very close to the limit of 300°F.
Staff requested that the applicant provides all the containment boundary O-ring temperatures and their temperature limits (main lid, cover plate, lance assembly, vent/drain, etc.) and explain how gaps are conservatively modeled before, during, and after the HAC fire. Staff suggested that the application should include a temperature contour plot showing the package fully engulfed (1475°F over the entire package) as well as a temperature versus time plot of key components (cladding, etc.) in order to have an efficient review.
Regarding the containment evaluation, staff requested an explanation on the potential for the thermocouple lance assembly (LTA) lateral slide, because the relations between the lance body (which caused the scuff marks as shown on slides 27/28) and the lance sheath, as well as the penetration sleeve sealing surface and its relation to the other components, need to be clearly understood and clarified. Staff said that a statement that the TLA will survive postulated 10 CFR 71.71 and 71.73 free and puncture drops with no loss of containment function is not acceptable:
this needs to be fully demonstrated in the application. Also, the applicant shall explain why there would not be a scuffed sealing surface in the TN-32 HBU cask to be transported.
Preliminary results for the shielding and criticality evaluations show the package in compliance with all regulatory limits: NCT and HAC dose rates are, at the very maximum, half of the regulatory limits and the upper subcritical limit for the current payload, calculated for most reactive fuel configuration, is 0.90874.
The TN-32B HBU cask demonstration project is a unique case. TN Americas, LLC, will be submitting, in December 2020, an application for a Part 71 CoC to support a one-time shipment in the October 2023 timeframe.
Staff made no regulatory commitment during the meeting.
Docket No. 71-9377 EPID L-2019-LRM-0029
Enclosures:
1-Meeting Attendees 2-Presentation
ML20309A976 (Pkg) ML20309A977 (Ltr) ML20309A978 (Encl)
OFC SFM E
SFM C
SFM NAME PSaverot SFigueroa JMcKirgan DATE 10/20/2020 10/20/2020 11/03/2020
Meeting Between TN Americas LLC and the Nuclear Regulatory Commission October 13, 2020 Meeting Attendees NRC/NMSS/DFM Pierre Saverot Antonio Rigato JoAnn Ireland Joe Borowski Jimmy Chang Dan Forsyth Eli Goldfeiz EPRI Keith Waldrop Orano Federal Services Gary Clark John McEntire Don McGee Dominion Energy David Tomlinson Eric Jones Tom Brookmire DOE Brayton Ford Ned Larson TN Peter Vescovi Nise Kaneza Ronda Jones SNL Sylvia Saltzstein Sam Durbin PNNL Brady Hanson