Californian nuclear operators are prioritizing swift fuel transfer and focusing resources on the regulatory and cost estimation challenges for upcoming decommissioning projects, project directors at SCE and PG&E, told the Nuclear Decommissioning and Used Fuel Strategy Summit on October 2.

In December 2016, Southern California Edison awarded the contract to decommission the San Onofre Nuclear Generating Station (SONGS) plant to a joint venture held by EnergySolutions and AECOM. The estimated cost of the decommissioning project is $4.4 billion and this covers dismantling, spent fuel management, radiological decommissioning and restoration of the site within 20 years.

SCE has moved ahead with the transferal of engineering and safety management systems over to the Decommissioning General Contractor (DGC) Jim Madigan, Director, Chief Nuclear Officer, Technical Adviser at Southern California Edison (SCE), told the conference.

"That started in May and we expect to have that done by the end of the year so that when we get the permit to start the work, the general contractor will be functioning completely on its own," he said.

A key challenge for decommissioning projects is shifting employee mindsets from operations to project management. Madigan said operators should put in place the Decommissioning General Contractor (DGC) as early as possible to ensure a swift transition into decommissioning tasks.

"It took us a while to get the DGC in place and then move to the project, out of that operational experience," he said.

A priority for the SONGS project in 2017 is the construction of a second IFSFI pad next to the site's existing ISFSI pad, Madigan said.

The construction of the pad itself is completed and "now we are just working on the security building and the final construction around the ISFSI pad," he said.

The project involved 200,000 man hours, handling 59,000 tons of materials, Madigan said.

"We were able to complete that work with only four first aids, no recordable injuries and no lost time injuries, a real tribute to the work that Holtec and their [subcontractors] did," he said.

Another key priority for SCE in 2017 is fuel transfer preparation and the company expects to complete a fourth successful dry run of fuel transfer in line with NRC regulations later this month, Madigan said.

"We'll probably start moving fuel before the end of the year," he said.

Swift fuel transfer into dry cask storage generates significant cost savings for operators by reducing monitoring and security requirements and cutting labor costs.

Earlier this year, NAC International set a record-low time for pool-to-pad fuel transfer at the 556 MW Kewaunee plant decommissioning project in Wisconsin.

NAC completed the transfer of 887 fuel assemblies from pool to pad in 23 weeks, using advanced fuel storage technology, licence amendments and a strong partnership with plant operator Dominion Energy to accelerate the process.

SCE's key priorities in 2018 include the transfer of all spent fuel to the newly-built IFSFI pad and the approval of environmental permits to start the demolition of the plant, Madigan said.

SCE has been working "tirelessly" with state regulators to gain the environmental permits and the company is also working closely with the NRC to make sure it has the necessary licence amendments in place by the end of fuel transfer process, he said.

Tackling regulation

Operators must not underestimate the significant interaction and timelines required for state and federal level permit approvals, Loren Sharp, Senior Director Nuclear Decommissioning Humboldt Bay Power Plant (HBPP) & Diabolo Canyon Power Plant (DCPP), Pacific Gas and Electric Company (PG&E), told the conference.

"Even starting two or three years in advance, we were pushing very hard to try and get Humboldt Bay to the point where we could continue operations and demolition with the permits we needed," he said.

Californian state regulations are notably rigorous, but federal level approvals are also time-consuming, Sharp said.

"As you go into federal and you are a shutdown plant, you don't have the priority that you do as an operating plant, for some of the approvals," he noted.

PG&E announced in June 2016 it would shut down its two 1.1 GW Diablo Canyon reactors by 2025, presenting a new decommissioning challenge for the company as it nears the end of its Humboldt Bay decommissioning project.

PG&E and its contract partners are close to completing major excavation work to install seismic wall supports at the Humboldt Bay site, Sharp said.

"We should be down at the very bottom of the excavation probably by the end of the year," he said

The company expects to complete all demolition and excavation works at Humboldt Bay by around 2018 and submit final status survey packages to regulatory authorities in 2019, Sharp said.

"In 2020, we hope to have NRC processing approvals for all those final status survey packages so we can get the part 50 [operator] license released," he said.

Cost calculations

Decommissioning cost estimates are a key challenge for operators and SCE plans to submit its latest estimates to the California Public Utilities Commission (CPUC) in 2018, under the regulated triennial cost approval process.

Cost estimates will also be a key priority for PG&E as it starts the process to acquire contractors for the Diabolo Canyon 1&2 project.

PG&E estimated the cost of the Diabolo Canyon decommissioning project at around $3.8 billion in the latest triennial CPUC cost review in 2016. Going forward, the operator must provide more detailed assessments.

"We are looking at creating a more detailed cost estimate as required by the CPUC board...We need to come in with a more accurate decommissioning estimate so that we can get our funding approved to get the budget right," Sharp said.

Nuclear Energy Insider