ML19123A208
| ML19123A208 | |
| Person / Time | |
|---|---|
| Site: | 07109362 |
| Issue date: | 05/03/2019 |
| From: | Pierre Saverot Spent Fuel Licensing Branch |
| To: | Christopher Regan Division of Spent Fuel Management |
| Saverot P | |
| References | |
| EPID L-2018-NEW-0003 | |
| Download: ML19123A208 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 3, 2019 MEMORANDUM TO: Christopher M. Regan, Deputy Director Division of Spent Fuel Management Office of Nuclear Material Safety and Safeguards FROM: Pierre Saverot, Project Manager /RA John McKirgan Acting for/
Spent Fuel Licensing Branch Division of Spent Fuel Management Office of Nuclear Material Safety and Safeguards
SUBJECT:
SUMMARY
OF APRIL 16, 2019 MEETING WITH DAHER NUCLEAR TECHNOLOGIES
Background
On April 16, 2019, a Category 1 public meeting was held at the U.S. Nuclear Regulatory Commission (NRC) headquarters in Rockville, MD, between the NRC staff and representatives from Daher Nuclear Technologies GmbH (DNT) to discuss proposed responses to the request for additional information (RAI) letter dated March 7, 2019 (ML19070A002).
The April 16, 2019, meeting was noticed on March 8, 2019 (ML19066A216). The meeting attendance list is provided as Enclosure No. 1.
Discussion By letter dated August 2, 2018, DNT submitted an application for certificate of compliance No.
9362 for the Model No. DN30 package, a new design for a protective structural packaging for UF6 cylinders.
DNTs proposed response to RAI 1-1, essentially a reference to the USEC-651 manual Uranium Hexafluoride: a Manual of Good Handling Practices, was deemed by the staff to be not helpful. Staff requested specific procedural details for filling, handling, testing, weighing and inspecting the cylinders and wanted to know, for example, if the leak test method described was a pre-shipment leak test or not, if the maintenance inspection requirements were for each use of the cylinder or for each shipment, if there was an inspection after the cylinder was filled, if the inspection described was a maintenance or a loading inspection, etc. Staff said that handling instructions need to be clear and detailed for staff to understand what the qualifications are for (i) a loaded 30B cylinder to be in a safe condition for transport, (ii) a cylinder to be filled or a cylinder no longer certified.
CONTACT: Pierre Saverot, NMSS/DSFM 301-415-7505
C. Regan Staff emphasized the need to remove from the current application all statements either with a vague wording or pertaining to the possible substitution of equivalent materials. Words such as significant, negligible, much better, small, slightly, etc., need to be quantified.
Alternatively, the applicant could provide, in some specific circumstances, an adequate justification that a qualitative wording is sufficient for the safety analyses.
DNT clarified the use of fully integrated solid and/or shell elements in the sensitivity analyses and the hourglass investigations. Staff agreed that negative volumes or negative Jacobians do not necessarily imply failure. In response to staffs questions, DNT confirmed that, since fully integrated element formulations are less stable in the case of large deformations, brick elements were used for the foam. DNT said that the drop testing data is aligned with the response results from the model. Staff asked DNT to include all such pertinent information in its response to RAI 2-2. Regarding RAI 2-10, Daher confirmed there was no deformation at the vent.
Regarding RAI 2-12, staff emphasized that stress strain curves developed from actual material testing shall be used to represent material No. 1.4301 (equivalent to ASTM A240 Type 304) rather than being derived mathematically. The staffs concern is that the point of uniform strain cannot be accurately determined otherwise. Beyond the point of uniform strain, necking in the material occurs and triaxiality effects need to be considered.
Staff said that the applicant has to either find the appropriate data (some data is available in the open literature) or use Non-Mandatory American Society of Mechanical Engineers (ASME)
Appendices EE and FF that do provide the material behavior beyond yield. This information should be incorporated into the LS-DYNA models, models need to be rerun, and all appropriate calculations shall be updated. Staff said that this could be done only for Sequence 1 if the applicant can make a convincing argument that all other sequences are bounded.
Regarding RAI 3-2, the applicant was told to comply with 10 CFR 71.73(c)(4) and recalculate temperatures with a surface absorptivity/emissivity of 0.9 during the fire phase. DNT clarified that 183°C was the solidus temperature of the tin-lead-solder which has a liquidus temperature of 216°C. The calculated temperatures for the valve/solder are below 183°C and the valve/solder maximum allowable temperature limit (that would continue to ensure structural integrity and ensure criticality safety during hypothetical accident conditions -HAC) is greater than 121 °C, but still less than 183°C.
Staff requested DNT to (i) clearly explain, in the application, why there was no integrity issue (the 30B cylinder is the containment boundary and must remain intact to ensure criticality safety), and (ii) perform a stress analysis to define admissible temperatures and show that limits are below their allowable values.
Staff emphasized that the response to RAI 3-5 shall be similar to the response for RAI 2-11 and be included in the revised application. Regarding RAI 3-6, staff said that the consequences resulting from any melted UF6 contents during HAC have not been correctly addressed in the proposed response.
Regarding RAIs 4-1 and 4-2, staff said that details of the leakage rate tests need to be included in Sections 1.8 and 1.9 of the revised application and that such details should include the types of tests (fabrication or pre-shipment), the components being tested, the test methodologies and standards, as well as personnel qualifications.
C. Regan The proposed criticality responses, including the validation report for the proposed contents, were deemed to be adequate and respond to staffs questions for the most part. However, staff required that the justifications to be provided for the most reactive UF6 fill levels, and for the amount of water ingress, shall be detailed.
DNT is now planning to submit a revised application by the end of June 2019. A certificate of compliance could be issued in the September or October timeframe, if all RAI responses are deemed to be both satisfactory and complete.
A member of the public asked a question about the possible licensing of a newly designed 30B cylinder for enrichments greater than 5 wt% with the use of the DN30. DNT responded that an application could be possibly submitted in late 2020.
Staff made no regulatory commitment during the meeting.
Docket No. 71-9362 EPID - L-2018-NEW-0003
Enclosure:
Meeting Attendees
C. Regan
SUBJECT:
SUMMARY
OF APRIL 16, 2019 MEETING WITH DAHER NUCLEAR TECHNOLOGIES, DOCUMENT DATE: May 3, 2019 DISTRIBUTION: SFST r/f, M. Layton, RPowell, RI BBonser, RII MKunowski, RIII JKatanic, RIV G:\SFST\Saverot\71-9362 DN30\meeting summary April162019.doc ADAMS No.: ML19123A208 OFC SFM E SFM C SFM NAME PSaverot SFigueroa JMcKirgan DATE 04/25/2019 04/26/2019 05/03/2019 OFFICIAL RECORD COPY
Meeting Between DAHER NUCLEAR TECHNOLOGIES (DNT) and the Nuclear Regulatory Commission April 16, 2019 Meeting Attendees NRC/NMSS/DSFM Pierre Saverot Antonio Rigato JoAnn Ireland Joe Borowsky Jeremy Smith Tae Ahn John Wise DNT Yara van Wijk Maik Hennebach Franz Hilbert PUBLIC Dale Lancaster Enclosure 1