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Underestimation of the Quantity of Plutonium at ATPu (Cadarache)
The French Atomic Energy Commission (CEA) admitted to the French Nuclear Safety Authority (ASN) in October 2009 that it had significantly underestimated the amount of plutonium in the glove boxes in the Workshop for Plutonium Technology (ATPu) at Cadarache, where MOX fuel was manufactured. When ATPu was in operation, the estimate was around 8 kilograms. In mid-October the CEA stated that it had recovered “on the order of 22 kilograms and that the total quantity could reach about 39 kg” [ASN Oct. 16 09].
ATPu ceased commercial operation in July 2003, because ASN judged the facility to be unable to withstand an earthquake. Between September 2003 and June 2008 Areva, the industrial operator, reconditioned and sent to La Hague the discards from manufacturing at the facility [IRSN]. A decree authorizing the definitive shut down and the dismantling of the installation was issued 6 March 2009.
On October 1, 2009 the adjunct general administrator of the CEA told the president of the Nuclear Safety Authority (ASN) orally that the 8-kilogram estimate of the amount of plutonium in the glove boxes was incorrect. ASN asked for a written declaration of the situation, which the CEA presented 6 October 2009 [Comets]. In a press release of 7 October, the CEA explained that the excess plutonium was in deposits not accessible to cleaners or visible until the glove boxes were taken apart.
ASN inspected ATPu 9 October 2009. At that time ASN learned that during the annual inventory in June 2009 Areva, the industrial operator of ATPu, had discovered that the amount of plutonium at certain posts exceeded the estimate for those posts. According to ASN, Areva “rapidly and regularly” informed the CEA, the licensee for the facility, of the situation, but the exchanges between Areva and the CEA were not tracked. Furthermore, the ASN inspectors were told during the October inspection that the CEA chose not to make the excess known until it had made an accurate determination of the amount of plutonium in the glove boxes and identified a way of correcting the situation [ASN 19 Oct. 09].
ASN asked the Institute for Radioprotection and Nuclear Safety (IRSN) to make an expert analysis of the situation. IRSN’s analysis stated that as far as IRSN was able to determine, the amount and the placement of plutonium at ATPu did not present a risk of a criticality but IRSN did not have all the information necessary to confirm how much plutonium was actually at the various posts at ATPu [IRSN].
On 14 October ASN ordered that work at ATPu be suspended. In its decision (2009-DC-160) ASN stated that the lack of an accurate inventory meant that “the prevention of the risk of a criticality was insufficiently ensured”, and that the plutonium represented a “serious and imminent risk.” On October 12 ASN had ranked the revelation of the discrepancy as a level 2 occurrence on the INES international scale of incidents [ASN 16 Oct. 09]..
ASN sent a written report of the situation to the court for possible judicial action. It did so on the grounds that it believed that the CEA violated the law of June 2006 on nuclear transparency and safety. The law requires that any incident or accident having or carrying a risk of having notable consequences on safety be reported immediately to ASN and to the relevant government official [ASN 19 Oct. 09].
The CEA in a press release of 15 October 2008 disputed the contention of ASN that it did not inform the safety authority of the discrepancy in the plutonium figure. It claims that 11 June 2009 it informed ASN orally that a discrepancy existed in regard to the first glove boxes dismantled. This oral report was part of an exchange relating to a visit by Euratom inspectors scheduled for 23 June. During the Euratom visit the CEA again signaled the discrepancy. The CEA also brought it to the attention of IRSN during an inspection of 1 and 2 July, the press release states. However, the CEA admits that in a declaration to ASN the operators wrote of the totality of the glove boxes at Cadarache and did not choose to discuss its “partial” knowledge of the plutonium at ATPu.
The Socialist Party and the Greens asked for the creation of a parliamentary inquiry commission on the situation at Cadarache.
In a letter of 19 October 2009 to the director of the CEA Cadarache, concerning the inspection of 9 October, the Marseille office of ASN laid out an extensive list of information that it requires no later than 20 November. The list includes details on all the glove boxes at ATPu and on methods of measurement and “a complete analysis of the Eurofab campaigns, the treatment of discards, and the impact of inventory errors on the safety of the posts concerned.”
The Office of the High Commission on Transparency and Information on Nuclear Safety held an extraordinary meeting 19 October to follow up a request for information from the minister of the state and minister of ecology, Jean-Louis Borloo, and to decide what actions to undertake concerning the discrepancy in the inventory at ATPu. The Commission decided upon five actions including asking EDF, Areva, the CEA, ASN, the General Department of Energy and Climate, and the High Official for Defense and Security to furnish information that would make possible an exact reconstruction of the flow of materials and waste in the fuel chain. It decided to organize a meeting of the High Commission for 20 November at which those concerned are to be auditioned.
As a follow-up to its written declaration of 6 October, the CEA asked all installations at Cadarache to draw up a complete accounting of the possible “retention” of nuclear materials. As a result of this initiative, the CEA announced 25 October that a larger than expected deposit of slightly enriched uranium (less than 1.65% uranium 235) had been found in a shielded cell in the STAR facility at Cadarache. The cell, C-1, is authorized to hold four kilograms of the uranium; ten kilograms are present. As its name indicates, STAR is dedicated to the treatment, cleansing, and reconditioning of irradiated reactor fuel. The cell was used between 1994 and 2006 to condition some twenty tons of old UNGG fuel (natural uranium—graphite gas fuel).
3 November 2009 ASN authorized the CEA to recommence dismantling at 22 of the 220 glove boxes still to be dismantled at ATPu. Each of the 22 contains no more than 200 grams of plutonium each.
ASN (Nuclear Safety Authority). Decision 2009-DC-160 of 14 October 2009.
ASN. Information Note (General). [ASN authorizes a limited recommencement . . .] 3 November 2009.
CEA (Atomic Energy Commission). Press announcement [Anomaly in the Technology of Plutonium Workshop]. 7 October 2009.
CEA. Press announcement [ATPu Incident: the CEA contributes details on the facts]. 15 October 2009.
CEA. Press announcement [Declaration of ASN on a discrepancy in the estimate of the quantity of nuclear material in the nuclear installation STAR of Cadarache]. 25 October 2009.
Comets, Mme. Marie-Pierre, ASN commissioner, in Minutes of a Hearing before the Commission for Sustainable Development of the National Assembly. 21 October 2009.
High Commission for Transparency and Information on Nuclear Safety. Press announcement [Extraordinary Meeting of the Office of the High Commission for Transparency and Information on Nuclear Safety]. 20 October 2009.
--Mary Byrd Davis, October 27, 2009
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