Problems of storage and transportation of SanOnofre high burnup nuclear fuel

ISSUES INVOLVING STORAGE AND TRANSPORTATION OF HIGH BURNUP NUCLEAR FUEL DECOMMISSION SAN ONOFRE By Marvin Resnikoff, Ph.D.SCE Community Engagement Panel (CEP)  San Juan Capistrano Community Center May 6, 2014“……… I’m going to briefly discuss transportation and storage of nuclear fuel, and I’m going to focus on high burnup nuclear fuel (HBF). What and why is HBF? NRC has not fully investigated the technical issues and implications, which in my view, are major and should have required careful study and an EIS. This is work that should have been done before the NRC allowed utilities to go to high burnup, not after. By high burnup, I mean fuel greater than 45 GWD/MTU, but in clearer terms, allowing each assembly to remain in the reactor longer. The implications are the radioactive inventory in HBF is greater.

NRC staff have focused on the heat in HBF, which is greater. But heat will decline over time. One implication is decommissioning will take longer. Fuel will sit in fuel pool for 20 years or more. San Onofre has high burnup fuel. The implication of a longer decay time is that the workers at the site will not be available for the decom process. Putting more fuel into the same space, moving from 24 fuel assemblies to 32, as Southern California Edison intends to do, will further the cooling off period. However, while heat is an important consideration, but perhaps of greater import is the impact on fuel cladding. It may surprise you to know that the NRC does not know how much HBF exists across the country. While the NRC has the power and the ability to identify how much HBF is at each reactor. The NRC has inspectors at each reactor. They simply have not made the effort. The Department of Energy (DOE) is conducting a survey which should be released in September. HBF has major implications for decommissioning, storage, transportation and disposal.

Storage Issues………….These are my takeaways on the HBF and storage issue:

• Little technical support for NRC approval of high burnup fuel (HBF). Experiment taking place in the field.
• Total amount of HBF unknown. At a minimum, the NRC should survey utilities.
• HBF will postpone storage up to 20 years; 32 PWR canister extends cooldown period.
• Cladding defects are a major problem for HBF; HBF may not be retrievable. HBF should be canned.
• Because of corrosion, long-term storage may not be possible in a salt environment.

Transportation Issues
Brittleness is important when considering transportation and disposal. One utility, Maine Yankee, has taken the important step of canning the HBF, that is, individually enclosing each fuel assembly in a stainless steel container. Concern is vibrations when transported, and potential shattering of cladding in a transportation accident. Transportation casks must satisfy regulatory accidents. Casks must withstand 30 foot drop onto an unyielding surface……….
Another type of accident involves fire. Several major train fires have occurred recently. 140 ton casks would be shipped by train, on the same routes used by oil tankers. Right now, nuclear fuel has nowhere to go, no final repository. But NRC has not done the statistical analysis to determine the statistical likelihood of a nuclear shipment caught in an oil tanker fire…………
Here are my takeways on the transportation issue:
• Realistic low probability, high consequence accidents should be examined.
• Side impact rail accidents may shatter HBF cladding.
• Long duration, high temperature fires may involve oil tankers that travel the same tracks. NRC has not properly quantified the statistical likelihood.
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