dresden


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

, 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 >

Bookmark and Share

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 >

Bookmark and Share

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 >

Bookmark and Share

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 >

Bookmark and Share

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 >

Bookmark and Share