ML18334A180
| ML18334A180 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/29/2018 |
| From: | Yoira Diaz-Sanabria Division of Spent Fuel Management |
| To: | Gilmore D San Onofre Safety |
| Marcano-Lozada J | |
| Shared Package | |
| ML18310A407 | List: |
| References | |
| LTR-18-0433 | |
| Download: ML18334A180 (2) | |
Text
From:
Diaz-Sanabria, Yoira To:
donnagilmore@gmail.com Cc:
Layton, Michael; Marcano, Jonathan
Subject:
Regarding your inquiry: Holtec Canister #30 at Southern California Edison (SONGS)
Date:
Thursday, November 29, 2018 4:19:42 PM
- Donna, I am responding to your inquiry sent on November 5, 2018 regarding Holtec canister #30 at SONGS. See information below.
Yoira Diaz-Sanabria Acting Deputy Division Director, Division of Spent Fuel Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Question Edison has Holtec canister #30 stored in a transfer cask. This is not an approved license condition. Transfer casks are not certified for storage, only for transfer of the thin-wall canister to the Holtec storage holes.
I want to know how you are cooling this canister in the transfer cask, since it is not designed for that.
Answer Following the August 3, 2018, misalignment incident, Southern California Edison (SCE) suspended all fuel handling activities. The suspension of fuel handling activities resulted in one of the multipurpose canisters, Number (No.) 30, being left in the transfer cask. The transfer cask is located in the cask washdown area of the Unit 3 fuel building.
The Final Safety Analysis Report (FSAR) has evaluated the placement of a multipurpose canister into a transfer cask. FSAR Section 4.5.4.3, described the thermal evaluations performed considering indoor ambient temperatures exceeding outdoor temperatures.
Conservative analyses performed by the cask vendor show the peak cladding temperature and canister pressure to be acceptable and the results are provided in FSAR Tables 4.5.2 and 4.5.9 (NRC ADAMS Accession No. ML17179A444). The staff review of this calculation is documented in the NRC Safety Evaluation Report Section 4.7.1.3 (ADAMS No.
While in the transfer cask, multipurpose canisters are cooled via natural convection heat transfer. Heat is transferred from the spent fuel, to the multipurpose canister, to the transfer cask, and ultimately to the air. Natural convection heat transfer has been demonstrated by the vendor to be sufficient to keep peak cladding temperatures below the acceptable limits. The licensee periodically monitors the transfer cask and the surrounding areas for radiation levels and temperature. All parameters have been found normal by the licensee.
In addition, the transfer cask was seismically restrained to a wall in the building. NRC Inspection report dated August 24, 2018 Section 1.2.b. (top of page 10) (NRC ADAMS
Accession No. ML18200A400) describes the restraint system and the NRCs review of this important to safety device.