Pilgrim addresses deteriorating protective panels
- Sep 14, 2017 10:55 am GMT
The solution was simply to change the configuration of the pool, moving the spent fuel rods away from storage racks where the panels were deteriorating, particularly the rods that were most recently in the reactor since they would be the hottest.
About 1,600 of the nearly 3,000 spent fuel assemblies were shifted, according to Pilgrim spokesman
The shift took place during the summer and has been assessed by inspectors with the
Heat and radiation have eaten away at the protective compound.
In the spent fuel pool environment, the minimum critical volume necessary to sustain a nuclear chain reaction may be as small as four fuel assemblies, NRC spokesman
Pilgrim's pool, originally designed to hold 880 spent fuel assemblies, currently holds 2,990 on racks under about 40 feet of water.
Early racks used to hold spent nuclear fuel assemblies were not clad with boron carbide because there was plenty of space between them. Once it became clear that nuclear waste was going to remain on reactor sites indefinitely rather than shipped to a federal repository, the pools were equipped with boron-clad racks so rods could be stored in a much tighter configuration than originally planned without a nuclear reaction occurring.
"There's a long history here,"
"NRC has kicked the can down the road, and kicked the can down the road, and kicked the can down the road," Lampert said. "And now, they are again allowing industry the cheap way out to deal with potential spent fuel pool criticality resulting from degraded boraflex panels."
"The real fix" would be to replace the deteriorated storage racks, Lampert said.
"That would be expensive and time-consuming," she said. "Instead, they get to play a game of checkers -- leave storage slots empty surrounding the deteriorated panels."
"Shuffling assemblies in the pool is a dance of danger," Turco said. "What would happen if the (deterioration) rate continued? It seems critical to move the fuel to dry casks now rather than having to answer that question."
Under Phase 2 of
The plan calls for filling another nine dry casks, adding to the eight currently loaded with 544 spent fuel assemblies and situated on a concrete pad outside the reactor building. Each cask holds 68 assemblies.
The shift to dry casks serves a dual purpose. Without emptying some spent fuel rods out of the pool, there would not be enough room in safe areas to store the hot fuel assemblies that will be removed from the reactor in
The nine new casks will allow for the removal of 612 assemblies, making room for the 580 currently in the nuclear reactor.
"For their plans, they are only a couple more years of operation," said Lochbaum, referring to Pilgrim's planned 2019 closure. "By moving the fuel in the pool, you're using distance as protection. The measure reduces dependence on boraflex."
When the reactor shuts down, the site will be storing 4,114 radioactive spent fuel assemblies -- with about 1,100 in dry casks and 3,000 in the pool. Currently there is no permanent or interim storage facility available to store the rods away from the
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