Monday, September 4, 2017

Nuclear Subsidy - Reprocessing Spent Fuel

Subtitle:  Yet Another Subsidy the Nuclear Power Industry Enjoys

The costs for spent nuclear fuel handling, storage, and disposal are yet another subsidy the commercial nuclear power industry enjoys.   This is estimated by General Accounting Office as $25 billion. 

Nuclear power for commercial electricity generation enjoys quite a number of government subsidies, including outright subsidies from state governments, construction loan guarantees for new reactors, almost complete indemnity from harm due to radiation releases (Price-Anderson Act), no lawsuits allowed during construction (with a minor exception), billing customers for construction funds, relaxing existing safety standards rather than enforcing them that would shut down a plant, government payment of 2.3 cents per kWh for 10 years for any new nuclear plant, and spent fuel disposal.  (see link to SLB article "US Nuclear Plants are Heavily Subsidized")  

Spent fuel handling and storage is an expensive, and critical aspect of nuclear power that is a burden to present and future generations.   From the NRC, the basics of the problem are shown below.   The key point is that approximately 80,000 metric tonnes (88,000 US tons) already exist in storage at more than 100 nuclear reactors in the US.   Approximately 60 percent more than that (140,000 metric tonnes, 154,000 US tons) is anticipated to ultimately exist in the US, if no new reactors are built and the others run as anticipated.  The US government has the burden of either reprocessing the spent fuel, or long-term storage of the highly radioactive waste.   The cost for the US to deal with the spent fuel is estimated at approximately $25 billion.  

Below is a list of spent fuel storage key points from the NRC: 

(see link to

Key Points:
Figure 1.   Diablo Canyon Nuclear Plant
 Dry Cask Spent Fuel Storage (red arrow)
photo: Google Maps 2017

1. All U.S. nuclear power plants store spent nuclear fuel in "spent fuel pools." These pools are robust constructions made of reinforced concrete several feet thick, with steel liners. The water is typically about 40 feet deep, and serves both to shield the radiation and cool the rods.

2. As the pools near capacity, utilities move some of the older spent fuel into "dry cask" storage. Fuel is typically cooled at least 5 years in the pool before transfer to cask. NRC has authorized transfer as early as 3 years; the industry norm is about 10 years.  (see Figure 1 for photo of dry cask storage area at Diablo Canyon Nuclear Plant)

3. The NRC believes spent fuel pools and dry casks both provide adequate protection of the public health and safety and the environment. Therefore there is no pressing safety or security reason to mandate earlier transfer of fuel from pool to cask.

4. After the September 11, 2001, terrorist attacks, the NRC issued orders to plant operators requiring several measures aimed at mitigating the effects of a large fire, explosion, or accident that damages a spent fuel pool. These were meant to deal with the aftermath of a terrorist attack or plane crash; however, they would also be effective in responding to natural phenomena such as tornadoes, earthquakes or tsunami. These mitigating measures include:

a. Controlling the configuration of fuel assemblies in the pool to enhance the ability to keep the fuel cool and recover from damage to the pool.

b. Establishing emergency spent fuel cooling capability.

c. Staging emergency response equipment nearby so it can be deployed quickly

5. According to the Congressional Research Service (using NEI data), there were 62,683 metric tons of commercial spent fuel accumulated in the United States as of the end of 2009.  (approximately 80,000 metric tonnes by end of year 2017)

a. Of that total, 48,818 metric tons – or about 78 percent – were in pools.

b. 13,856 metric tons – or about 22 percent – were stored in dry casks.

c. The total increases by 2,000 to 2,400 tons annually.  (end key points from NRC)

Diablo Canyon Nuclear Plant - spent fuel storage

The particulars of spent fuel storage, both dry cask and spent fuel pool, are shown below for Diablo Canyon (DCPP). (source:  NRC document ML111290158)

"Spent (used) fuel at DCPP is stored in two different systems:

Spent Fuel Pools - Wet Storage: Much of the spent fuel is stored in the Spent Fuel Pool, a
reinforced concrete structure with a stainless steel plate liner. Shielding and protection of the
spent fuel in the pools is provided by maintaining 23 feet of borated water over the spent fuel.

Heat is removed by a cooling system which constantly re-circulates the spent fuel pool water through heat exchangers. The base of the pools are below grade level, on bedrock, and the walls of lower portions of the pools are also below grade, such that the top of the spent fuel storage racks are near the exterior ground level to the east of the Auxiliary Building. DCPP has redundant capabilities to add water into the spent fuel pool – even with the loss of electrical power.

Independent Spent Fuel Storage Installation (ISFSI) - Dry Storage: 

Older spent fuel is stored at the ISFSI in dry casks, which are totally sealed from the environment in a Multi-purpose Canister (MPC) that is constructed of stainless steel. The MPC is placed into a massive overpack that is over 20 feet tall, and is constructed out of two steel vessels, each 1 inch thick, with the space between the vessels filled with approximately 28 inches of concrete. The overpacks shield against radiation exposure and encapsulate and protect the MPCs. The dry casks are seismically qualified and anchored to a steel reinforced concrete pad over 7 feet thick.

The dry casks utilize a totally passive cooling system that requires no electricity or pumping to safely cool the fuel. Rather, the system uses naturally occurring convection to pull cool air in at the bottom and allow warmer air to exit the top of the cask like a chimney." 

Roger E. Sowell, Esq.
Marina del Rey, California
copyright (c) 2017 by Roger Sowell - all rights reserved

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