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Anticipated Transient Without Scram

, director, Nuclear Safety Project

Role of Regulation in Nuclear Plant Safety #8

In the mid-1960s, the nuclear safety regulator raised concerns about the reliability of the system relied upon to protect the public in event of a reactor transient. If that system failed—or failed again since it had already failed—the reactor core could be severely damaged (as it had during that prior failure.) The nuclear industry resisted the regulator’s efforts to manage this risk. Throughout the 1970s, the regulator and industry pursued non-productive exchange of study and counter-study. Then the system failed again—three times—in June 1980 and twice more in February 1983. The regulator adopted the Anticipated Transient Without Scram rule in June 1984. But it was too little, too late—the hazard it purported to manage had already been alleviated via other means. Read more >

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Obstruction of Injustice: Making Mountains out of Molehills at the Cooper Nuclear Plant

, director, Nuclear Safety Project

The initial commentary in this series of posts described how a three-person panel formed by the Nuclear Regulatory Commission (NRC) to evaluate concerns raised by an NRC worker concluded that the agency violated its procedures, policies, and practices by closing out a safety issue and returning the Columbia Generating Station to normal regulatory oversight without proper justification.

I had received the non-public report by the panel in the mail. That envelope actually contained multiple panel reports. This commentary addresses a second report from another three-person panel. None of the members of this panel served on the Columbia Generating Station panel. Whereas that panel investigated contentions that NRC improperly dismissed safety concerns, this panel investigated contentions that the NRC improperly sanctioned Cooper for issues that did not violate any federal regulations or requirements. This panel also substantiated the contentions and concluded that the NRC lacked justification for its actions. When will the injustices end? Read more >

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24 Space-Based Missile Defense Satellites Cannot Defend Against ICBMs

, co-director and senior scientist

Articles citing a classified 2011 report by the Institute for Defense Analysis (IDA) have mistakenly suggested the report finds that a constellation of only 24 satellites can be used for space-based boost-phase missile defense.

This finding would be in contrast to many other studies that have shown that a space-based boost-phase missile defense system would require hundreds of interceptors in orbit to provide thin coverage of a small country like North Korea, and a thousand or more to provide thin coverage over larger regions of the Earth. Read more >

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More Comments on the IDA Boost-Phase Missile Defense Study

, co-director and senior scientist

Part 1 of this post discusses one aspect of the 2011 letter from Missile Defense Agency (MDA) to then-Senator Kyl about the IDA study of space-based missile defense. The letter raises several additional issues, which I comment on here. Read more >

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Pipe Rupture at Surry Nuclear Plant Kills Four Workers

, director, Nuclear Safety Project

Role of Regulation in Nuclear Plant Safety #7

Both reactors at the Surry nuclear plant near Williamsburg, Virginia operated at full power on December 9, 1986. Around 2:20 pm, a valve in a pipe between a steam generator on Unit 2 and its turbine inadvertently closed due to a re-assembly error following recent maintenance. The valve’s closure resulted in a low water level inside the steam generator, which triggered the automatic shutdown of the Unit 2 reactor. The rapid change from steady state operation at full power to zero power caused a transient as systems adjusted to the significantly changed conditions. About 40 seconds after the reactor trip, a bend in the pipe going to one of the feedwater pumps ruptured. The pressurized water jetting from the broken pipe flashed to steam. Several workers in the vicinity were seriously burned by the hot vapor. Over the next week, four workers died from the injuries. Read more >

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