10 results for month: 10/2008


Is there a point to the Sodium Cooled Fast Reactor?

For two generations Argonne National Laboratory has obsessively pursued the development of the liquid sodium breeder reactor. Although Argonne claims they have solved all safety issues related to the liquid sodium breeder, in fact significant safety issues remain, and indeed lists of remaining research tasks related to the liquid sodium breeder reactors indicate a lack of assurance about safety claims being made about the LMFBR. In addition to safety concerns, there are cost questions. Sodium cooled reactor carry a significant cost penalty over conventional LWRs. An 1998 Essay by Lawrence M. Lidsky and Marvin M. Miller of the Massachusetts Institute ...

Fermi's folly, Wigner's wisdom

Both Eugene Wigner and Enrico Fermi were brilliant scientists. Both made enormous contributions to the theoretical and practical development of atomic energy. Their educational background was different, and for this reason their thinking about long-range reactor design diverged. Fermi was a classic physicist. Fermi thought of reactors first in terms of physics experiments. The CP-1--the ancestor of almost all solid fuel reactors--was first of all a physics experiment. Physicists depend on other people to deliver to them the materials they need to conduct their experiments. Once the materials are present, they are assembled, and the physicist ...

A Primer on Nuclear Safety: 2.6 Defense in Depth

A Primer on Nuclear Safety:2.6 Defense in DepthMolten Salt Reactors, Moir-Teller DefensesIntroductionThe term Molten Salt Reactor is generic. All reactors that use liquid salts as both coolant and fuel carrier are Molten Salt Reactors. Reactors that use Liquid Fluoride salts, and operate on a thorium rather than a uranium fuel cycle are Liquid Fluoride Thorium Reactors. Most discussions about Molten Salt Reactor safety are primarily directed to LFTR safety, but many of the safety features of the the LFTR will also be present in other MSRs.Many of the safety features of the LWR are not required for the MSR. For example the massive steel pressure ...

A Primer on Nuclear Safety: 2.5 Defense in Depth

A Primer on Nuclear Safety:2.5 Defense in DepthThe Pebble Bed Reactor OptionDuring the late 1940's research began in Oak Ridge on safe reactor designs.Farrington Daniels was a pioneering advocate of the practical use of solar energy. Daniels had been, during World War II, assistant director of the University of Chicago Metallurgical Laboratory chemistry devision. The Metallurgical Laboratory was the great incubator of reactor designs. Daniels had done research on the concept of using a furnace filled with small balls or pebbles to fix nitrogen from air. Daniels developed the idea of building a reactor along somewhat similar lines to the pebble ...

A Primer on Nuclear Safety: 2.4 Defense in Depth

A Primer on Nuclear Safety:2.4 Defense in DepthA Brief Note on ESBWR SafetyHow Safe is the ESBWR? Given a probabilistic approach to nuclear safety, we first note that the ESBWR designers at General Electric have estimated that a likelihood of core meltdown every 29 million years. But a core meltdown is far from a release of a large amount of radiation from the reactor into the environment. Thus we must look at the likelihood of a failure of not only the pressure vessel, but of the core catcher, a system designed to trap and contain molten material from the core and to prevent its movement outside the reactor containment system. The core catcher is a ...

A Primer on Nuclear Safety: 2.3 Defense in Depth

A Primer on Nuclear Safety:2.3 Defense in DepthLight Water Reactors - Water and other safety featuresThe most important aspect of safety in Light Water Reactors is the cooling system. The coioling system also serves te purpose of moderating the nuclear reaction in Light water reactors. As we have noted, a loss of coolant in Light Water Reactors will stop the chain reaction, but will lead to core overheating because of the continued core heating caused by the radioactive decay of fission products. For that reason it is vital to maintain the presence of cooling water in the reactor core. There is one major variation in the LWR cooling system. ...

A Primer on Nuclear Safety: 2.2 Defense in Depth

A Primer on Nuclear Safety:2.2 Defense in DepthControlling Nuclear Reactions in Light Water ReactorsEnrico Fermi was the first nuclear scientist to find a solution for controlling chain reactions in a nuclear reactor. Fermi said that his Chicago Pile was "a crude pile of black bricks and wooden timbers." Of course natural uranium fuel was added. There was, Fermi realized, something else needed in order to make his reactor safe. That was a means of soaking up the neutrons created by the chain reaction in order to control it. The way Fermi chose to control the Chicago Pile was to insert a number of cadmium-coated control rods into the reactor. ...

A Primer on Nuclear Safety: 2.1 Defense in Depth

A Primer on Nuclear Safety:2.1.1 Defense in DepthLight Water Reactors - Physical BarriersThe Defense in Depth philosophy is applied to the release of radioactive materials from inside the core of light water reactors. Helen Caldicott, the ceaseless critic of nuclear power notesNuclear power creates massive quantities of radioactive isotopes, which are classified as nuclear waste. Among these materials are strontium 90, . . cesium 137 . . . plutonium, . . . plutonium has a radioactive life of half a million years. It enters the body through the lung, where it is known to cause cancer. It mimics iron in the body. Hence it migrates to the bone, where ...

A Primer on Nuclear Safety: 2.0 Defense in Depth

A Primer on Nuclear Safety:2.0 Defense in Depth In 1964, Ralph Nader had no reason to question that nuclear power was a clean, safe, cost-efficient technology. Then he attended a conference at the Oak Ridge National Laboratory. Over lunch, Nader began asking nuclear engineers some penetrating questions. "They couldn't answer them, or the answers weren't satisfactory," Nader recalls. "'What could happen if a system goes wrong?' I asked. They avoided any such descriptions or said, 'we've got defense in depth' -- and other jargon." - David Bollier (Citizen Action and Other Big Ideas)The concept of defense in depth is fundamental to nuclear safety. The ...

Thorium Energy Independence and Security Act of 2008

The following legislation has been introduced in the US Senate today by Senator Orrin Hatch and Senator Harry Reid:110TH CONGRESS2D SESSIONTo amend the Atomic Energy Act of 1954 to provide for thorium fuel cycle nuclear power generation.IN THE SENATE OF THE UNITED STATESintroduced the following bill; which was read twiceand referred to the Committee onA BILLTo amend the Atomic Energy Act of 1954 to provide for thorium fuel cycle nuclear power generation.Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled,SECTION 1. SHORT TITLE.This Act may be cited as the "Thorium Energy Independence and ...