Two nuclear reactor designs slated for use in the United States could be safer than existing plants if a prolonged power outage occurred, a federal safety taskforce said Wednesday in a report examining lessons learned from the Japanese earthquake and nuclear crisis.
The U.S. Nuclear Regulatory Commission taskforce said the designs of Westinghouse Electric Co.'s AP1000 reactor and GE Hitachi Nuclear Energy's ESBWR reactor include systems that could cool hot, radioactive fuel for three days. Those emergency cooling systems are powered by gravity and evaporation, which do not require electricity.
Taskforce members have recommended that existing nuclear plants be able to cool the radioactive core of its reactors and spent nuclear fuel for the same 72-hour period.
The crisis in Japan put renewed focus on the ability of nuclear plants to survive a loss of electricity needed to run cooling systems. A March 11 earthquake off Japan caused a massive tsunami that struck the Fukushima Dai-ichi plant, disabling the backup power systems needed to keep the plant's radioactive fuel cool. The plant suffered multiple meltdowns, explosions and spewed radiation into the environment.
Taskforce members recommended the NRC move forward with finalizing the rules for the AP1000 and the ESBWR reactors, a necessary step before either design could be built in the United States. It said that utilities hoping to build those new reactor designs should be required to pre-position emergency equipment near their plant that could be used to cope with a disaster.
"By nature of their passive designs and inherent 72-hour coping capability for core, containment, and spent fuel pool cooling with no operator action required, the ESBWR and AP1000 designs have many of the design features and attributes necessary to address the Task Force recommendations," the report said. "The Task Force supports completing those design certification rulemaking activities without delay."
A coalition of environmental groups have asked the NRC to halt all licensing of new reactors and power plants until regulators can more thoroughly review the crisis in Japan. The coalition has also asked the NRC to restart the review process for the AP1000 after regulators uncovered last-minute design problems.
"I think there are still some outstanding questions," said Tom Clements of the environmental watchdog group Friends Of The Earth.
In May, NRC Chairman Gregory Jaczko said that Westinghouse failed to properly model potential stresses on its AP1000 reactor, including the combined forces that an earthquake and changing temperatures could inflict on the reactor shield building. That massive concrete-and-steel structure protects sensitive reactor equipment from debris flung by a tornado, hurricane or even a crashing jetliner. Westinghouse said none of the modeling issues were significant, although NRC staffers are still analyzing the company's responses.
Westinghouse has contracts to build its AP1000 reactors in Florida, Georgia and South Carolina. Utilities firms in Alabama and North Carolina earlier submitted applications to the NRC seeking to use the same technology. Four AP1000 reactors are under construction in China.
DTE Energy has proposed building an ESBWR reactor on the site of an existing power plant in Newport, Mich.
Ray Henry can be reached at http://www.twitter.com/rhenryAP.