Heather MacLean talks about her job as a Nuclear Engineer for Idaho National Laboratory.
For more information about INL careers, visit http://www.facebook.com/idahonationallaboratory.
Duration : 0:1:34
Dec
9
Dec
2
Health officials say a radioactive form of hydrogen that leaked from a Vermont nuclear plant into soil and groundwater has reached the nearby Connecticut River. State Department of Health Commissioner Dr. Harry Chen said Wednesday water samples from the shoreline near the Vermont Yankee nuclear plant last month tested positive for small amounts of tritium, a radioactive isotope of hydrogen that’s been linked to cancer when ingested in large amounts. Gov. Peter Shumlin wants more wells to pull contaminated water from the ground on the Vermont Yankee site. He says he’s “very concerned.” Tritium has leaked from nuclear plants around the country. It’s particularly problematic for Vermont Yankee as it seeks to renew its license. New Orleans-based plant owner Entergy Corp. is suing Vermont in federal court over the state’s efforts to shut the plant down.
http://hisz.rsoe.hu/alertmap/site/?pageid=event_desc&edis_id=NC-20110818-32001-USA
Duration : 0:1:50
Nov
8
U.S. Atomic Energy Commission
Idaho Operations Office
SL-1 The Accident: Phases I and II
A13886VNB1
Describes this nuclear accident from the point of view of the Atomic Energy Commission.
Considering the time, this film report is exceptionally candid about the vulnerabilities of nuclear reactors. This first civilian reactor accident was especially gruesome in that one of the reactor operators was shot into the ceiling by an expelled reactor vessel plug and control rod. Views of the internal wreckage are fascinating. The cause of this accident has never been determined, although operator error has been alleged.
Documentaries of this quality are rare in the U.S. nuclear community, at least for the general public.
Producer: U.S. Atomic Energy Commission; Creative Commons license: Public Domain
The SL-1, or Stationary Low-Power Reactor Number One, was a United States Army experimental nuclear power reactor which underwent a steam explosion and meltdown in January 1961, killing its three operators. The direct cause was the improper withdrawal of the only movable control rod. The event is the only fatal reactor accident in the United States.
The facility, located at the National Reactor Testing Station approximately forty miles (60 km) west of Idaho Falls, Idaho, was part of the Army Nuclear Power Program and was known as the Argonne Low Power Reactor (ALPR) during its design and build phase. It was intended to provide electrical power and heat for small, remote military facilities, such as radar sites near the Arctic Circle, and those in the DEW Line. The design power was 3 MW (thermal). Operating power was 200 kW electrical and 400 kW thermal for space heating. NASA system failure studies have cited that the core power level reached nearly 20 GW in just four milliseconds, precipitating the reactor accident and steam explosion.
On December 21, 1960, the reactor was shut down for maintenance, calibration of the instruments, installation of auxiliary instruments, and installation of 44 flux wires to monitor the neutron flux levels in the reactor core. The wires were made of aluminum, and contained slugs of aluminum-cobalt alloy.
On January 3, 1961 the reactor was restarted after a shutdown of eleven days. Maintenance procedures commenced, which required the main central control rod to be withdrawn a few inches; at 9:01 p.m. this rod was withdrawn almost to the top of the core, causing SL-1 to go prompt critical. In four milliseconds, the heat generated by the resulting enormous power surge caused water surrounding the core to begin to explosively vaporize. The water vapor caused a pressure wave to strike the top of the reactor vessel. This propelled the control rod and the entire reactor vessel upwards, which killed the operator who had been standing on top of the vessel, leaving him pinned to the ceiling by a control rod. The other two military personnel, a supervisor and a trainee, were also killed. The victims were Army Specialists John A. Byrnes and Richard L. McKinley and Navy Electrician’s Mate Richard C. Legg.
Reactor principles and events
Fission produces neutrons with a wide range of energies. In all light-water-moderated reactors (LWR), to sustain fission of the U-235 the reactor core needs to have water present to moderate (slow down) the neutrons produced by the nuclear reaction. This process is called “thermalizing” and increases the probability of the neutrons causing fission. When reactivity is inserted in the reactor core, more neutrons are available and power rises. Several factors limit the increase in power.
The first limiting factor is that, given a proper initial spectrum of neutron energies, water has a negative reactivity coefficient. Having a negative reactivity coefficient means that, as the water heats up, the molecules are farther apart (water expands and eventually changes phase) and neutrons are less likely to hit hydrogen atoms, so fewer neutrons are thermalized by collisions with the hydrogen in the water and the probability of fission decreases. This removes reactivity from the core. The lower the temperature, the closer the molecules, the greater the number of neutrons thermalized and the greater the core reactivity. It is also possible to design a reactor core that has an entirely different neutron energy spectrum such that it has conditions for which water has a positive reactivity coefficient. A graphite-moderated, water-cooled reactor like the RBMK reactors at Chernobyl may have a positive reactivity coefficient for coolant (water) temperature.
Duration : 0:40:23
Oct
10
DemocracyNow.org -
Japan is on the verge of a nuclear catastrophe after a third explosion at the Fukushima Daiichi nuclear power plant, which was heavily damaged by Friday’s 9.0-magnitude earthquake and tsunami. The blast seriously damaged the plant’s Number Two reactor’s steel containment structure, causing nearby radiation levels to rise to eight times the legal limit for exposure in a year. Plant workers “were manually opening valves into into these containments to keep the pressure from building up,” says nuclear engineer Arnie Gundersen, in an interview with Democracy Now! March 15. “I would suspect that a lot of those efforts have been abandoned because of high radiation levels,” Gundersen says.
Arnie Gundersen has been nuclear industry executive for many years before blowing the whistle on the company he worked for in 1990, when he found inappropriately stored radioactive material. He is now chief engineer at Fairewinds Associates.
For the video/audio podcast, transcript, to sign up for the daily news digest, and for more coverage of the Japan disaster, visit http://www.democracynow.org/tags/japan_disaster
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Duration : 0:9:30
Oct
3
The highly radioactive nuclear waste at the Hanford Nuclear Reservation on the Columbia River in southcentral Washington state could be cleaned up at least 35 years faster than originally estimated, due to an agreement reached between two federal agencies and the state of Washington. The waste is the legacy of 45 years of nuclear weapons production. It amounts to about 60 percent of all the high-level nuclear waste in the United States. Drawing on the ideas that emerged from a year-long partnership with its contractors and state and federal regulators, DOE developed a plan for cleanup that dramatically reduces risks to people and the environment. Creative Commons license: Public Domain.
Duration : 0:15:26
Sep
17
Nuclear fuels researcher Jon Carmack talks about the satisfactions of a career in nuclear engineering.
For more information about nuclear energy careers, visit http://www.facebook.com/idahonationallaboratory.
Duration : 0:2:12