cooper


Benny Hill Explains the NRC Approach to Nuclear Safety

, director, Nuclear Safety Project

The Nuclear Regulatory Commission’s safety regulations require that nuclear reactors be designed to protect the public from postulated accidents, such as the rupture of pipes that would limit the flow of cooling water to the reactor. These regulations include General Design Criteria 34 and 35 in Appendix A to 10 CFR Part 50.

Emergency diesel generators (EDGs) are important safety systems since they provide electricity to emergency equipment if outside power is cut off to the plant—another postulated accident. This electricity, for example, would allow pumps to continue to send cooling water to the reactor vessel to prevent overheating damage to the core. So the NRC has requirements that limit how long a reactor can continue operating without one of its two EDGs under different conditions. The shortest period is 3 days while the longest period is 14 days. Read more >

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Cooper: Nuclear Plant Operated 89 Days with Key Safety System Impaired

, director, Nuclear Safety Project

The Nebraska Public Power District’s Cooper Nuclear Station about 23 miles south of Nebraska City has one boiling water reactor that began operating in the mid-1970s to add about 800 megawatts of electricity to the power grid. Workers shut down the reactor on September 24, 2016, to enter a scheduled refueling outage. That process eventually led to NRC special inspections. Read more >

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Nuclear Plant Containment Failure: Overpressure

, 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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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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Browns Ferry Barbeque

, director, Nuclear Safety Project

Fission Stories #195

Workers restarted the Unit 1 boiling water reactor (BWR) at the Browns Ferry Nuclear Plant near Athens, Alabama in early November 2014 following a routine refueling outage. Read more >

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