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The “Race” to Resolve the Boiling Water Reactor Safety Limit Problem

, former director, Nuclear Safety Project

General Electric (GE) informed the Nuclear Regulatory Commission (NRC) in March 2005 that its computer analyses of a depressurization event for boiling water reactors (BWRs) non-conservatively assumed the transient would be terminated by the automatic trips of the main turbine and reactor on high water level in the reactor vessel. GE’s updated computer studies revealed that one of four BWR safety limits could be violated before another automatic response terminated the event.

Over the ensuring decade-plus, owners of 28 of the 34 BWRs operating in the US applied for and received the NRC’s permission to fix the problem. But it’s not clear why the NRC allowed this known safety problem, which could allow nuclear fuel to become damaged, to linger for so long or why the other six BWRs have yet to resolve the problem. UCS has asked the NRC’s Inspector General to look into why and how the NRC tolerated this safety problem affecting so many reactors for so long. Read more >

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Nuclear Plant Emergency Preparedness – Re-HAB

, former director, Nuclear Safety Project

Disaster by Design/ Safety by Intent #38

Disaster by Design

It takes two to tango.

It takes a village to raise a child.

It takes between the tango and the child-rearing numbers to respond to a nuclear plant accident. Read more >

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Nuclear Plant Containment Failure: Overpressure

, former director, Nuclear Safety Project

Disaster by Design/Safety by Intent #30

Disaster by Design

Defense-in-depth is a primary element of the Nuclear Regulatory Commission’s approach to the safety of U.S. nuclear power plants. Many of the NRC’s regulatory requirements seek to reduce the chances of reactor core meltdowns to as low as achievable levels. But recognizing that the consequences of low probability events like meltdowns, sometimes called “black swans,” can be disastrous, the NRC also has regulatory requirements seeking to reduce the chances that radioactivity gets released in harmful amounts during an accident. This commentary describes the primary containments used in pressurized water reactors (PWRs) and boiling water reactors (BWRs) and how too much pressure can cause containment to fail. Read more >

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Problems with “Infrequently Performed Tests” at Nuclear Plants

, former director, Nuclear Safety Project

Disaster by Design/Safety by Intent #19

Disaster by Design

IPTE in the nuclear industry stands for Infrequently Performed Tests or Evolutions. It describes the measures applied before undertaking planned activities that are not routinely conducted. When tasks are performed on a daily or weekly basis, workers develop proficiencies that are maintained by habit. But when workers have not performed a task in quite a while, it is possible that their awareness of the proper steps has diminished, or that the proper steps have been revised.

If familiarity breeds contempt, lack of familiarity breeds confusion. And confusion at the controls of a nuclear power plant is seldom helpful. Read more >

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Command and Control

, former director, Nuclear Safety Project

Disaster by Design/Safety by Intent #17

Disaster by Design

Command and control is often used to describe the authority of military leaders in directing armed forces in battle. It can also refer to senior managers at nuclear power plants and the resources they command and control to fend off safety challenges.

Faulty intelligence, or flawed situational awareness, undermines command and control when leaders have the wrong understanding of hazards and/or response capabilities. Read more >

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