All About Meltdowns

Submitted by Anonymous on Fri, 2012-01-20 13:20

All About Meltdowns

Excerpts from the

Reactor Safety Study (WASH-1400)

(commonly known as the Rasmussen Report)

published by the
US Nuclear Regulatory Commission
1974
http://www.ccnr.org/rasmussen.html

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HOW LIKELY IS A CORE MELT ACCIDENT?

Submitted by Anonymous on Fri, 2012-01-20 13:57.

HOW LIKELY IS A CORE MELT ACCIDENT?

The Reactor Safety Study carefully examined the various paths leading to core melt. Using methods developed in recent years for estimating the likelihood of such accidents, a probability of occurrence was determined for each core melt accident identified. These probabilities were combined to obtain the total probability of melting the core.

The value obtained was about one in 20,000 per reactor per year...

http://www.ccnr.org/rasmussen.html#2.11

On the validity of WASH-1400

Submitted by Anonymous on Sun, 2012-01-22 10:29.

From wikipedia on WASH-1400

A panel of scientists organized by the American Physical Society (APS) "found much to criticize" in the WASH-1400 report. The panel noted that fatality estimates had considered only deaths during the first 24 hours after an accident, although radioactive cesium released in an accident would remain active for decades, and could expose large populations to adverse effects. The APS reviewers argued that cancer, one of the most serious forms of illness resulting from a reactor accident, would not show up until years after the accident. The APS reviewers also criticized the report’s methods for predicting the performance of emergency cooling systems.

The Union of Concerned Scientists released a 150-page report critiquing the WASH-1400 report, and in June 1976, the House Subcommittee on Energy and Environment held hearings on the validity of the report's findings. As a result of these hearings, NRC agreed to have a review group examine the validity of the report's conclusions.

In a 1978 report, the review group appointed by the NRC and led by Professor Harold Lewis of the University of California concluded that "the uncertainties in WASH-1400's estimates of the probabilities of severe accidents were in general, greatly understated".

In 1979, The NRC was forced to issue a policy statement in which it accepted numerous criticisms of WASH-1400 raised by the Lewis Committee, and it withdrew any endorsement of the executive summary.