ML080570498
| ML080570498 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 02/27/2008 |
| From: | John Marshall NRC/NMSS/FCSS/FCLD/MCAB |
| To: | Melanie Wong NRC/NRR/ADRO/DORL/LPLII-1 |
| References | |
| TAC MD8013 | |
| Download: ML080570498 (4) | |
Text
February 27, 2008 MEMORANDUM TO:
Melanie Wong, Acting Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM:
Jane Marshall, Chief
/RA/
Material Control & Accounting Branch Fuel Facility Licensing Directorate Division of Fuel Cycle Safety and Safeguards Office of Nuclear Material Safety and Safeguards
SUBJECT:
REQUEST FOR EXEMPTION - DUKE POWER COMPANYS DECEMBER 3, 2007, REQUEST FOR EXEMPTION FROM 10 CFR 74.19(c) REQUIREMENTS REGARDING PHYSICAL INVENTORY (TAC NO. MD8013)
As requested in a telephone discussion with John Stang of your staff on February 4, 2008, Material Control and Accounting Branch staff reviewed the physical inventory-related exemption dated December 3, 2007, for the McGuire Nuclear Station Unit 1 spent fuel pool storage racks. The completed Safeguards Evaluation Report is attached.
We consider this effort to be closed. If you have any questions concerning this response, please contact me at (301) 492-3138.
Enclosure:
As stated
February 27, 2008 MEMORANDUM TO:
Melanie Wong, Acting Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM:
Jane Marshall, Chief
/RA/
Material Control & Accounting Branch Fuel Facility Licensing Directorate Division of Fuel Cycle Safety and Safeguards Office of Nuclear Material Safety and Safeguards
SUBJECT:
REQUEST FOR EXEMPTION - DUKE POWER COMPANYS DECEMBER 3, 2007, REQUEST FOR EXEMPTION FROM 10 CFR 74.19(c) REQUIREMENTS REGARDING PHYSICAL INVENTORY (TAC NO. MD8013)
As requested in a telephone discussion with John Stang of your staff on February 4, 2008, Material Control and Accounting Branch staff reviewed the physical inventory-related exemption dated December 3, 2007, for the McGuire Nuclear Station Unit 1 spent fuel pool storage racks. The completed Safeguards Evaluation Report is attached.
We consider this effort to be closed. If you have any questions concerning this response, please contact me at (301) 492-3138.
Enclosure:
As stated DISTRIBUTION:
MCAB r/f FFLD r/f JStang, NRR ML080570498 OFC NMSS/FCSS/MCAB NMSS/FCSS/MCAB NMSS/FCSS/MCAB:BC NAME MKelly TPham JMarshall DATE 02/26/08 02/27/08 02/27/08 OFFICIAL RECORD COPY
DOCKET:
50-369 LICENSEE:
Duke Power Company, LLC FACILITY:
McGuire Nuclear Station, Unit 1
SUBJECT:
SAFEGUARDS EVALUATION REPORT: LETTER DATED DECEMBER 3, 2007, PHYSICAL INVENTORY EXEMPTION REQUEST FOR THE MCGUIRE UNIT 1 FACILITY BACKGROUND By letter dated December 3, 2007, McGuire Nuclear Station requested an exemption from the requirement in 10 CFR 74.19(c) to conduct a physical inventory of loose fuel pellets stored in a container (a pellet can) located in the Unit 1 spent fuel pool (SFP) storage racks. The regulation requires licensees conduct a physical inventory of all special nuclear material (SNM) in its possession at intervals not to exceed 12 months.
In 1986, a fuel assembly (D03) was found to have been damaged, and this resulted in fuel pellets being released from some of the assemblys fuel rods. This event was documented in a Licensee Event Report (369/86-13), and was discussed in Inspection Reports 50-369/86-19 and 50-370/86-19.
The loose fuel pellets were vacuumed and were placed, along with the vacuum filters, in a pellet can (PCAN01). A metal plate was placed on top of the filters, and the pellet can was placed into a storage cell (PP-45) in the Unit 1 SFP.
Title 10 CFR 74.19(c) requires that each licensee conduct a physical inventory of all SNM in its possession at intervals not to exceed 12 months. This would require the loose fuel pellets and fuel fragments within the pellet can from fuel assembly D03 to be visually verified during a physical inventory.
Past inventory practices for the pellet can were limited to a visual verification that the pellet can was in the location specified by the SNM inventory record database. The loose pellets and fuel fragments within the pellet can were not visibly verified. The licensee believes that conducting a physical inventory consistent with the regulation would require undertaking an effort to recover, separate, and secure each loose pellet and fuel fragment within the pellet can, which would impose a significant hardship and regulatory burden. That effort would require the development of specialized tools and processes which may result in the potential spread of contamination within the SFP water. The filters have degraded over time, and removal of the loose pellets and fuel fragments from the container would be difficult as a result of the material being entangled within the filter medium.
Until the 2007 physical inventory, the pellet can had not been moved or lifted since its initial placement into the SFP in 1986. During the inventory, a video inspection of the interior of the canister indicated that the contents of the pellet can had not been disturbed. A plate can be seen, and small segments of the filter medium can also be seen around the edges of the plate, consistent with the description of the pellet can contents previously provided.
Since the loose pellets in the container are not visible, an underwater radiation detector was used to acquire dose rate measurements as part of the 2007 physical inventory.
The results of this verification (11 R/hr) confirmed multiple pellets (up to 5-6) reside within the canister. The licensee believes that utilizing this technique provides an acceptable alternative means of complying with 10 CFR 74.19(c) requirements.
However, the alternate technique of using a radiation detector to meet the regulatory requirements has certain drawbacks. The container that stores the pellet can was constructed onsite because, at the time of the event, no commercial containers were available to store the recovered material. Degradation of the pellet can was observed when it was moved during the 2007 physical inventory. During handling, removal of the steel mesh screen was necessary, since it was partially unattached. To take radiation readings of the pellet can, the container must be moved to a low dose area in the SFP.
Due to the method used to handle the pellet can and the degradation of the container, there is a potential risk of dropping at least some of the fuel pellets.
The licensee proposes that, instead of using a radiation monitor, a video inspection of the interior of the container will be performed during the physical inventory to verify that the contents have not been disturbed since the previous inspection, which would not require canister movement. They request this exemption until such time that the pellet can is placed into an appropriate container, or no later than December 31, 2010.
DISCUSSION As noted above, the licensee believes that conducting a physical inventory consistent with the regulation would require undertaking an effort to recover, separate, and secure each loose pellet and fuel fragment within the pellet can. This is an overstatement.
During inventory, the licensee would only be expected to confirm that there is no evidence that any SNM is missing from the can. If the can cannot be accessed or safely opened, then using a radiation monitor to acquire dose rate measurements, which could then be compared to previous readings, would be a sufficient verification measure for inventory purposes.
However, because of the concerns cited by the licensee with repeating the radiation readings, the very small amount of SNM involved, and the licensees plan to place the pellets into another, more easily verifiable, container by late 2010, the licensees request to undertake a video inspection of the canister containing the pellet can for inventory purposes is considered adequate.
RECOMMENDATION The staff recommends that the licensees exemption request from the inventory requirements of 10 CFR 74.19(c) be granted for pellet can PCAN01 until the pellet can is relocated into another container, or until December 31, 2010, whichever occurs first.
Until that time, the canister containing the pellet can shall undergo a video inspection during inventory of the SFP.
PRINCIPAL CONTRIBUTORS Michael Kelly Thomas Pham