sequoyah


Tennessee Valley Authority’s Nuclear Safety Culture Déjà vu

, director, Nuclear Safety Project

The Nuclear Regulatory Commission (NRC) issued a Confirmatory Order to the Tennessee Valley Authority (TVA) on July 27, 2017.  An NRC team inspecting the Watts Bar Nuclear Plant in fall 2016 determined that TVA failed to comply with elements of another Confirmatory Order that NRC had issued to TVA on December 22, 2009. Specifically, the 2009 Confirmatory Action required TVA to implement measures at all its nuclear plant sites (i.e., Watts Bar and Sequoyah in Tennessee and Browns Ferry in Alabama) to ensure that adverse employment actions against workers conformed to the NRC’s employee protection regulations and whether the actions could negatively impact the safety conscious work environment. The NRC inspection team determined that TVA was not implementing several of the ordered measures at Watts Bar. Read more >

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TVA’s Nuclear Allegators

, director, Nuclear Safety Project

The Nuclear Regulatory Commission (NRC) receives reports about potential safety problems from plant workers, the public, members of the news media, and elected officials. The NRC calls these potential safety problems allegations, making the sources allegators. In the five years between 2012 and 2016, the NRC received 450 to 600 allegations each year. The majority of the allegations involve the nuclear power reactors licensed by the NRC. Read more >

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Nuclear Plant Containment Failure: Pre-Existing Damage

, director, Nuclear Safety Project

Disaster by Design/Safety by Intent #31

Disaster by Design

Federal regulations require that nuclear plant containments withstand the temperature, pressure, hydrodynamic forces, humidity, and other consequences from design basis accidents and limit the amount of radioactivity to the atmosphere. By limiting the radioactivity release, containments minimize the harm to nearby populations and the environment.

The surest way for a containment to be damaged after an accident and be unable to fulfill this safety function is for it to be damaged before the accident starts. Read more >

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Spent Fuel Damage: Pool Criticality Accident

, director, Nuclear Safety Project

Disaster by Design/Safety by Intent #29

Disaster by Design

Disaster by Design/Safety by Intent #26 described a progression leading to overheating and damage to a reactor core, often labeled a meltdown. Disaster by Design/Safety by Intent #27 described the damage to a reactor core that can result from reactivity excursions. Disaster by Design/Safety by Intent #28 and #29 mirror those commentaries by describing how irradiated fuel stored in spent fuel pools can experience damage from overheating and reactivity excursions. Read more >

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Flooding at the Nuclear Plant

, director, Nuclear Safety Project

Disaster by Design/Safety by Intent #1

Disaster by Design

The March 2011 disaster at the Fukushima Daiichi nuclear plant in Japan did not reveal flooding to be a nuclear safety hazard; it reminded us of this well-known threat. Flooding from internal sources (e.g., broken pipes and failed storage tanks) and from external sources (e.g., heavy rainfall and swollen rivers) had long been recognized as a risk to be managed with an array of flood protection measures. As the following summaries—an abridged sampling among many such events—indicate, there were numerous reminders before Fukushima. Read more >

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