1. Diablo Canyon Independent Spent Fuel Storage Installation (ISFSI)
Dry Fuel Management Topics
Jearl Strickland
Interim Leader, Technical Services PG&E
June 21, 2016

2. Topics
Status of Independent Spent Fuel Storage Installation (ISFSI) pad construction
Update on the long range fuel transfer to the ISFSI
Update of activities related to the potential for external corrosion of multi-purpose canisters (MPCs) in storage

3. ISFSI Facility Construction
Design capacity for the ISFSI is 138 HI-STORM casks. These are arranged on 7 pads of 20 locations each
First two pads constructed
Beginning 2009, loaded casks placed on these pads
Five additional pads constructed in 2014
Initial use in 2016
No issues of note during construction

4. Completed ISFSI Storage Pads

5. Dry Fuel Storage Plan
To maintain compliance with NRC requirements, four older fuel assemblies must surround each newer fuel assembly.
As there are 193 assemblies in the reactor core, 772 assemblies must be maintained in the spent fuel pool to accommodate the core offload.
DCPP strategy is to approach the 772 limit in 2016, and maintain at that level going forward.
Final state for the spent fuel pool is to be emptied approximately 10 years after final shutdown when the decay heat level has reached the allowable value for the cask license.

6. Dry Fuel Storage Statistics
Used Fuel Outage (UFO) History & Projections
Start
Finish
Casks from Unit 1/2
UFO1
6/11/2009
8/17/2009
8/0
UFO2
5/3/2010
7/10/2010
0/8
UFO3
1/16/2012
3/17/2012
3/4
UFO4
8/5/2013
10/1/2013
3/3
UFO5
5/25/2015
7/5/2015
5/3
UFO6
8/8/2016
11/6/2016
6/6
UFO7
6/4/2018
8/25/2018
4/5
UFO8
5/18/2020
8/8/2020
4/4
UFO9
8/1/2022
10/29/2022

7. Spent Fuel Locations
Unit 1 SFP :
972 assemblies

8. Assemblies in Spent Fuel Storage Pool

9. 2015 EPRI. All Rights Reserved.
MPC Potential for External Corrosion Activities
Primary mechanism for external corrosion is chloride-induced stress corrosion cracking when canisters of susceptible material and tensile stresses reach an external temperature that facilitates a corrosive environment. Industry is collaborating with U.S. NRC on resolving this issue (ref. RIRP N-10-01).
2015 EPRI. All Rights Reserved.

10. MPC Potential for External Corrosion Activities
PG&E continues to actively support EPRI and NEI efforts on this issue.
April 28, 2016: NRC met with industry representatives and interested stakeholders to discuss closure of the chloride induced stress corrosion cracking Regulatory Issue Resolution Protocol (RIRP).
NEI and NRC expect formal closure of the RIRP within the next few weeks.
NEI, NRC, and EPRI representatives recapped milestones in improved understanding of the potential for stress corrosion cracking of welded stainless steel canisters.

11. MPC Potential for External Corrosion Activities
EPRI Program Timeline

12. Thank You
Jearl Strickland