Immediate decommissioning of closed U.S. reactors

Nuclear Monitor Issue: 

(April 9, 1999) The Connecticut Yankee nuclear power plant (616 MW) was closed definitely in December 1996. In connection with plans to build a gas-fired plant on site, the utility now opts for immediate decommissioning to allow the site to be released from oversight by the Nuclear Regulatory Commission (NRC) for unrestricted use.

(508.4996) WISE Amsterdam - It is planned to complete dismantling of the nuclear reactor around 2004. The latest cost estimate of decommissioning was US$427 million, but it is being revised, as required by the National Regulatory Commission, which will take several months. The owner of Connecticut Yankee is expected to choose in April an engineering company for construction of the gas-fired plant and/or decommissioning. Two US firms have bidded for the job, which includes four options:

  1. construction of a gas-fired plant on site;
  2. construction of a dry cask spent fuel storage;
  3. maintenance of the spent fuel pool;
  4. evaluation of site-cleaning so that releases do not exceed a 10-millirem standard.

(The NRC regulations only call for cleanup to a 25 mrem standard, but the utility asked for cost estimates to reach the lower limit). The winning bidder for construction of the gas plant would probably also get the decommissioning job.

Up to now a gas plant has never been built on the site of a once- operational nuclear reactor with nuclear fuel on site. It has been considered in the UK, but was dismissed as too dangerous because of the risk of gas explosions. The proposal of a group of local residents, officials and plant employees, Repower Advisory Committee (Repac), is to site the gas plant at a parking lot. In that case the spent fuel has to be moved to another part of the site, which covers 525 acres (210 hectare = 2.1 square km) in total.

At the Zion two-unit nuclear plant (2x 1085 MW), closed in January 1998, the option of building a gas plant with nuclear fuel on site is now also being considered. A study of that proposal is being undertaken by Amoco Corp. Decommissioning costs of Zion-2 alone are estimated at US$800 million.
In 1998 another nuclear utility decided to quickly decommission its San Onofre 1, 450-MW nuclear plant, which was closed in 1992 and put at cold storage. It is planned to begin next year and will take about eight years. Its decommissioning costs are estimated at US$460 million. Local residents are not concerned about the costs, but about the possible storage of nuclear wastes, which have to be shipped to the nuclear waste storage at Barnwell. But the reactor parts are too heavy for road or train transport, so they must be cut into pieces or stored on site.


  • AP, 19 February 1999
  • Nucleonics Week, 11 March 1999

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