dresden


Exelon Generation Company (a.k.a. Nuclear Whiners)

, director, Nuclear Safety Project

The Unit 3 reactor at the Dresden Nuclear Power Station near Morris, Illinois is a boiling water reactor with a Mark I containment design that began operating in 1971. On June 27, 2016, operators manually started the high pressure coolant injection (HPCI) system for a test run required every quarter by the reactor’s operating license. Soon after starting HPCI, alarms sounded in the main control room. The operators shut down the HPCI system and dispatched equipment operators to the HPCI room in the reactor building to investigate the problem.

The equipment operators opened the HPCI room door and saw flames around the HPCI system’s auxiliary oil pump motor and the room filling with smoke. They reported the fire to the control room operators and used a portable extinguisher to put out the fire within three minutes. Read more >

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Nuclear Plant Containment Failure: Isolation Devices

, director, Nuclear Safety Project

Disaster by Design/Safety by Intent #32

Disaster by Design

Containment structures at nuclear power plants have multiple purposes. Containments protect vital safety equipment from damage caused from external events like high winds and the debris they can fling. And containments protect nearby communities against radiation released from reactor cores damaged during accidents. Read more >

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Ill Prepared

, director, Nuclear Safety Project

Disaster by Design/Safety by Intent #14

Disaster by Design

Disaster by Design/Safety by Intent #13 described the cost-beneficial safety upgrades identified, but not implemented, by the owner of the Indian Point nuclear plant upwind and upriver of New York City and its millions of inhabitants.

The commentary mentioned that the Nuclear Regulatory Commission’s regulations required the owner to perform the analysis, called the Severe Accident Mitigation Alternatives (SAMA) analysis, but not to implement cost-beneficial safety upgrades. As stupid and irresponsible as that sounds, it is the case as shown—in black & white—of the NRC’s evaluation of cost-beneficial safety upgrades for the two boiling water reactors at the Dresden nuclear plant upwind of Chicago and its millions of inhabitants (Fig. 1). Read more >

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When Safety Relief Valves Fail to Provide Safety or Relief at Nuclear Plants

, director, Nuclear Safety Project

Disaster by Design: Safety by Intent #6

Disaster by Design

The light water reactors currently operating in the U.S. are either boiling water reactors (BWRs) or pressurized water reactors (PWRs). In both designs, water flowing past the nuclear fuel in the reactor cores gets heated to over 500°F. Water is able to be heated to this temperature because it is pressurized—to over 1,000 pounds per square inch (psi) in BWRs and to over 2,000 psi in PWRs. The 1,000 psi pressure is equivalent to the pressure submerged more than 2,200 feet below the ocean’s surface. Read more >

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Nuclear Pipe Nightmares

, director, Nuclear Safety Project

Disaster by Design/Safety by Intent #4

Disaster by Design

If you had a dollar for every foot of pipe—or even just a quarter for every three inches of pipe—used in the nation’s nuclear power plants, you would probably not be reading this post. That chore would be delegated to one or more of your many minions.

Pipes at nuclear power plants carry cooling water to the reactor vessel and spent fuel pool, transport steam to the main turbine, provide hydrogen gas to cool the main generators, supply fuel and lubricating oil to the emergency diesel generators, maintain the fire sprinklers ready to extinguish fires, and numerous other vital functions. Given so many pipes, a success rate of 99.99%—remarkably similar to a failure rate of one broken pipe out of ten thousand pipes—would result in lots of piping failures. Read more >

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