Photo: Mohawk Watershed Group at UnionUn laboratoire qui avait la mission de trouver des moyens de purifier le plutonium et l'uranium usagé des centrales nucléaires pour en faire des bombes nucléaires, le Knolls Atomic Power Laboratory, à Niskayuna dans l'état de New York se fait démanteler et réhabiliter depuis 2008. Mais les pluies abondantes du 25 octobre 2010 ont provoqué un débordement d'eaux radioactives qui se sont déversées dans la Mohawk River. Une pompe défectueuse est la cause du débordement de 630 gallons d'eaux contaminées contenant du césium-137, du strontium-90, de l'uranium et du plutonium.
Pourtant, le porte-parole régional du DEC (Department of Environmental Conservation) dit qu'il n'y a pas de danger imminent pour la santé publique, même si ces éléments sont des substances cancérigènes reconnues. Les officiels du labo ont dit au DEC que "l'exacte composition de la matière déversée est inconnue pour le moment" selon l'infraction émise le 3 novembre par le DEC contre Knolls pour avoir enfreint le U.S. Clean Water Act. Aucune pénalité n'a été annoncée.
Le déversement a été causé par une pompe électrique défectueuse et a duré pendant 3 heures. La porte-parole de l'installation dit que le matériel radioactif dans les 630 gallons déversés dans la rivière est le même que l'équivalent contenu dans le volume habituel de la rivière Mohawk pendant 2 minutes. On s'assure que l'évènement ne se reproduira plus. On ajoutera un voyant sur le panneau de contrôle pour monitorer la pompe qui a fait défaut et on ajoutera un bassin de rétention en cas qu'une autre panne se reproduise. De plus, l'eau sera traitée sur un autre site à l'avenir.
Il y a 2 ans, Knolls avait commencé à nettoyer le sol radioactif de son site représentant environ 5 acres des 170 acres que la compagnie possède le long de la rivière. L'installation date du début des années 1950, pour répondre à un besoin du fédéral. En décembre 2007, un octroi de $69 million avait été accordé pour la décontamination du site. Le travail a commencé en septembre 2008. En avril 2009, le fédéral accorda un autre $32 million pour aider à payer pour la décontamination.
Un autre article dans The New York Times mentionne que dans un autre évènement en septembre, des travailleurs avaient traînés des matériaux radioactifs avec leurs souliers. Jamais personne n'a reçu de doses radioactives dangereuses selon les autorités, mais la décontamination nécessaire après ces 2 évènements coûteront probablement plus de $1 million. Le contracteur, URS Corporation de San Francisco pourrait perdre sa job. L'état de New York pourrait pénaliser la compagnie pour avoir déversé des substances défendues dans la rivière.
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"Radioactive leak from Knolls cleanup site
Hundreds of gallons of radioactive water from a cleanup at the Knolls Atomic Power Laboratory spilled from a drainage pipe into the Mohawk River last month, according to the state Department of Environmental Conservation. A failed sump pump system caused about 630 gallons of tainted water -- containing Cesium-137, Strontium-90, uranium and plutonium -- to overflow into a culvert draining directly into the river, DEC reported.
DEC regional spokesman Rick Georgeson said the water came from storm drainage caused by heavy rains Oct. 25 at the River Road site, where a cleanup of pollution left behind by Cold War-era nuclear weapons research has been going on since 2008. Georgeson said the spill did not present any immediate threat to public health. However, the elements in the spill are known carcinogens.
Officials at the lab told DEC that the "exact composition of the discharge is unknown at this time," according to a Nov. 3 citation issued by DEC against Knolls for violation of the U.S. Clean Water Act. No penalty has yet been announced. Caused by a failed electrical pump, the spill lasted for about three hours from the Separation Process Research Unit, located on the west side of the Knolls property.
Knolls spokeswoman Anne LaRoche said that the radioactive material in the estimated 630 gallons that passed through the pipe during that time was the same as the naturally emitted radiation contained in two minutes' worth of the Mohawk's average flow. LaRoche said the lab was taking measures to ensure the incident isn't repeated, including the addition of sump-pump monitors on the main control panel and the addition of a collector tank in case another pump failure occurs. In addition, the facility will in future treat its water offsite.
Two years ago, Knolls began a cleanup of radioactive soil, which covers about five of the facility's 170 acres along the Mohawk River, including two buildings. It dates to the early 1950s, when the federal government researched nuclear weaponry. In December 2007, DOE awarded a $69 million cleanup contract to Washington Group International of Oak Ridge, Tenn. Work began in September 2008. In April 2009, the federal government announced a $32 million stimulus grant to help pay for the cleanup. The facility is divided into three sections: the upper level, which is near buildings G2 and H2; the lower level, which included a parking lot, a staging area for rail shipments; and the north field, which was used to store radioactive slurry waste.
The unit, operational for less than three years before closing in 1953, focused on research into recovering uranium and plutonium from spent nuclear fuel."
Excerpts from article written by Brian Nearing published here: http://www.timesunion.com/local/article/Radioactive-leak-from-Knolls-cleanup-site-803666.php
WASHINGTON — Several hundred gallons of water contaminated with radioactive materials from a 1950s nuclear research site spilled into the Mohawk River near Schenectady on Oct. 25, prompting an investigation by the United States Energy Department.
The site, part of the Knolls Atomic Power Laboratory, in Niskayuna, was used to develop the technology for purifying plutonium for nuclear bombs. A rainstorm washed 600 to 800 gallons of water containing plutonium, uranium and trace amounts of two other radioactive substances, strontium and cesium, into the river, according to a letter sent by the New York State Department of Environmental Conservation to the Energy Department and to a contractor working to clean up the site. Officials said the amount of radioactive material released into the river was no more than the amount that would naturally flow by the site every two minutes.
In a separate episode in September, workers tracked radioactive materials into clean areas on their shoes, according to the Energy Department. Neither event gave a significant radiation dose to anyone, according to federal and state officials, but the cleanup prompted by the two errors is likely to cost more than $1 million.
The Energy Department is trying to quickly decommission the site, using money from the stimulus bill. The Energy Department’s principal deputy assistant, Dae Chung, said that the contractor, URS Corporation of San Francisco, might be fired. In addition, New York State could fine the company for unauthorized discharges into the river.
“Obviously no system is perfect,” Mr. Chung said. “Every now and then, infrequently, we get into a contamination event.” He said the investigation would look for “root causes” to try to prevent a repetition.
A spokesman for the contractor did not respond to a telephone message on Tuesday afternoon.
The water that spilled was supposed to have been collected and pumped to a purification unit, but the pump failed, according to the state agency. The spill was reported Saturday by The Daily Gazette of Schenectady.
Source: http://www.nytimes.com/2010/11/10/nyregion/10nuke.html?_r=1
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