The Pilgrim Nuclear Power Plant near Plymouth, Massachusetts has been operating since 1972. During the forty years of operation, it has generated a great deal of nuclear waste in the form of spent fuel rods. The reactor at the plant is a GE Mark 1 model. This is exactly the same model of reactor in use at the Fukushima plant in Japan that suffered the disaster in March of 2011. In this model of reactor, the spent fuel pool is situated above the reactor. The spent fuel pool at Pilgrim was originally designed to temporarily hold nine hundred fuel assemblies. Today, there are almost four thousand fuel assemblies in the spend fuel pool. The operators of the plant say that, so far, the spent fuel has been manageable.
At the current rate of operation, the spent fuel pool will be full within two years. If alternative storage is not available by then, the reactor will have to be shut down. In light of this situation, Entergy, the company that owns and operates the Pilgrim plant is in the process of building dry casks at the Pilgrim plant to hold spent fuel assemblies to allow the plant to keep operating. Although security at the plant is very tight and critics have not been allowed inside to document the work being done, it is known that workers are constructing a wide road that will provide a path to move the big dry casks from the reactor building to a nearby concrete pad where they will be kept.
Anti-nuclear activists are challenging the permitting process for the casks and the storage pad. They agree that something must be done with the spent fuel that is piling up but they want the current construction permit cancelled and a new process started which will include public review of the construction plans and public hearings. They seem to be primarily focused on the siting and construction of the concrete support pad that will hold the dry casks.
Personally, I am more concerned about the dry casks. Dry casks for storing radioactive wastes have been around for decades but recently there has been growing concern that the waste in some of the casks may be corroding the lining of the casks and may also be generating dangerous hydrogen gas which could cause an explosion and rupture of the casks.
Research on improved cask design is being carried out. It includes the incorporation of sensors into the casks in order to monitor the interior conditions in real time and warn of possible problems. The first prototype of the new design of dry cask will not be available until 2017 at the earliest. If I were the anti-nuclear activists in Plymouth, I would insist that the new casks being constructed at the Pilgrim plant are built according to the new designs being developed. If they are based on the old cask designs, then the storage of spent fuel in the casks at Pilgrim may cause serious accidents and radioactive releases in the future.
