It is ‘unclear’ whether the potential risk reduction due to lower amounts of decay heat and cesium in spent fuel pools would offset the real increase in risks, operational impacts and costs associated with accelerating the transfer of used nuclear fuel from pool to dry storage, according to a study from the Electric Power Research Institute.

The study is an updated version of a 2010 report, which examines the benefits and impacts associated with accelerating the transfer of used nuclear fuel from spent fuel pools to dry storage at nuclear power plants.

The report, updated in August 2012, evaluates two scenarios: one in which the transfer of fuel from spent fuel pools to dry storage would take 10 years to implement, and one in which the transfer would take 15 years.

Key findings are that spent fuel inventories would drop by 67-78% for a representative pressurized water reactor plant and by 73-78% for a representative boiling water reactor plant. The source term for cesium would also be reduced by almost half (43-53% for a PWR plant and 47-48% for a BWR plant), according to the report.

On the other hand, the study found that accelerating the programme would come at a radiological and economic cost.

There would be a ‘significant increase in worker radiation exposure,’ estimated at 1650 person-rem and 2090 person-rem for the 10-year and 15-year scenarios, respectively.

The economic impact to the US nuclear industry would be around $3.5-$3.9 billion above current operating costs, the study estimates. This includes costs associated with procurement of dry cask storage systems, cask loading operations, dry storage facility construction, and annual operation and maintenance.

Other factors that need to be considered with programme acceleration include increased occupational safety hazards such as the need to handle thermally hot transfer casks as well as the increased accident risk associated with fuel drop or cask drop during loading operations.

The study is expected to be useful in informing policy and operational decisions regarding the handling and management of used nuclear fuel, EPRI said, noting that a ‘comprehensive assessment’ should be made before any policy changes. The full report (number: 1025206) can be downloaded from the EPRI website.