Floating Nuclear Power Plants: A Technical Solution to a Land-based Problem (Part I)

Thomas Wellock
NRC Historian
 

In July, Russia announced it planned to build the world’s first floating nuclear power plant to supply 70 megawatts of electricity to isolated communities. If successful, the plan would bring to fruition an idea hatched in the United States nearly a half-century ago.

It’s not widely known, but in 1971, Offshore Power Systems (OPS), a joint venture by Westinghouse Corporation and Tenneco, proposed manufacturing identical 1,200 MW plants at a $200 million facility near Jacksonville, Fla. Placed on huge concrete barges, the plants would be towed to a string of breakwater-protected moorings off the East Coast. Using a generic manufacturing license and mass production techniques, Westinghouse President John Simpson predicted this approach could cut in half typical plant construction time and make floating reactors economical.

While Simpson touted their economic advantages, utilities wanted floating power plants to overcome mounting opposition to land-based reactors. Site selection had ground to a near halt in the Northeast and the West Coast due to public opposition, seismic worries and environmental concerns. In July 1971, a federal court complicated siting further by forcing the NRC’s predecessor, the Atomic Energy Commission, to develop thorough Environmental Impact Statements for nuclear plant projects.

In fact, West Coast utilities met defeat so often on proposed coastal power plant sites they turned inland in an ill-fated move to find acceptable arid locations. By heading out to sea, Northeast utilities hoped they could overcome their political problems.

Drawing from a 1978 GAO report.
Drawing from a 1978 GAO report.

New Jersey’s Public Service Electric and Gas Corporation (PSEG) responded enthusiastically and selected the first site, the Atlantic Generating Station, about 10 miles north of Atlantic City at the mouth of Great Bay. A PSEG spokesman said floating reactors were “the only answer to the problem of siting nuclear power plants.” Other reactor vendors, including General Electric, also studied the possibility of floating reactors.

A supportive regulatory response heartened OPS officials. The AEC’s Advisory Committee for Reactor Safeguards issued a fairly positive assessment of floating reactors in late 1972. “We think this is a very favorable letter,” a Westinghouse official said of the committee response, “and we don’t see any delay whatsoever.”

Westinghouse moved forward with its grand plan and built its manufacturing facility near Jacksonville. The facility included a gigantic crane that was 38 stories high — the world’s tallest.

It appeared to be smooth sailing ahead for floating plants with a RAND Corporation study that touted their superior ability to withstand earthquakes and other natural hazards. Spoiler alert: RAND selected for floating power plants one of the most ill-conceived yet prescient of acronyms, FLOPPS.

Exactly how the seas turned rough for floating plants will be unveiled in Part II on Thursday.

Transporting Spent Nuclear Fuel: How Do We Know It’s Safe?

John Cook
Senior Transportation Safety Scientist
Division of Spent Fuel Storage and Transportation
 

In May, we talked about changes to NRC regulations regarding shipments of nuclear materials – including spent fuel. This month, we wanted to share the results of a periodic evaluation of the risk posed by spent fuel shipments. The NRC expects to publish the final study later this year. A draft was published in 2012.

Microsoft Word - diagram-typical-trans-cask-system-2.docSpent fuel shipments are strictly regulated and have not released any radioactive materials since they began more than 30 years ago. But the NRC still periodically evaluates the risks. As more data become available and computer modeling improves, these studies allow us to refine our understanding of these risks.

The latest study, Spent Fuel Transportation Risk Assessment, modeled the radiation doses people might receive if spent fuel is shipped between various sites. The study confirmed that NRC regulations for spent fuel transport are adequate to ensure safety of the public and the environment.

Both the NRC and the U.S. Department of Transportation oversee radioactive material transport. DOT regulates shippers, vehicle safety, routing, and emergency response. The NRC certifies shipping packages for the more hazardous radioactive materials, including spent fuel.

To be NRC-certified, a package must provide shielding, dissipate heat, and prevent a nuclear chain reaction. It must also prevent the loss of radioactive contents under both normal and accident conditions. The package must be able to survive a sequence of tests meant to envelope the forces in a severe accident. These tests include a 30-foot drop onto an “unyielding” surface (one that does not give, so the package absorbs all the force), a puncture test drop onto a steel peg, and then a 1475-degree Fahrenheit fire that engulfs the package for 30 minutes.

The 2013 risk assessment examined how three NRC-certified packages would behave during both normal shipments and accidents. It modeled a variety of transport routes using population data from the 2000 census, as updated in 2008. It used actual highway and rail accident statistics. It considered doses from normal shipments to people living along transportation routes, occupants of vehicles sharing the route, vehicle crew and other workers, and anyone present at a stop. And it used state-of-the-art computer models. The risk assessment found:

 Doses from routine transport would be less than 1/1000 the amount of radiation people receive from background sources each year

 There is less than a 1 in 1 billion chance that radioactive material would be released in an accident

 If an accident did release radioactive material, the dose to the most affected individual would not cause immediate harm

The 2013 risk assessment builds on earlier studies of transportation risks. It uses real-world data and equipment in place of generic designs and conservative assumptions. The first study, done in 1977, allowed the NRC to say that its transport regulations adequately protect public health and safety. Other studies done in in 1987 and 2000 found the risks were even smaller than the 1977 study predicted. These studies, together with analyses we perform on major transportation accidents, previous physical testing of package performance, and the global experience with thousands of completed spent fuel shipments, give the NRC confidence in the safety of spent fuel shipments.

For more information on how the NRC regulates spent fuel transportation, click here. To read our updated backgrounder on the subject, click here.