| I. MATERIALS > SOURCES AND STOCKS > French sources and stocks of reprocessed uranium |
The reprocessing of each ton of standard PWR fuel produces almost a ton of reprocessed uranium (URT), 960 kg to be exact; and La Hague reprocesses about 1600 t/yr of fuel. It is impossible for us to know precisely the final destination of all of the reprocessed uranium.
France has three plants for the conversion of uranyl nitrate: Cogéma’s TU2 and TU5 and Comurhex’s Ateliers pilotes. They can transform a total of about 3000 t/yr into U308, UO2 or even UF4, but these installations are incapable of using UF4 in great quantity.
There is no French installation for large scale conversion into UF6 (uranium hexafluoride) of the UF4 originating from the reprocessing. The Comurhex “Ateliers pilots” convert only about 350 tons per year. According to a publicity document in 1994, there were plans for “imminent construction at Comurhex [of a unit] for the transformation of UF4 (from reprocessing) into UF6 with the objective of new enrichment [Cogema 94b]. However, no precise plan has ever been announced.
Nor is there any enrichment installation for URT. At this time, URT-based UF6 is exported for enrichment. In 1996, the National Evaluation Commission for Research on managing radioactive waste (CNE) asked where the enrichment of reprocessed uranium would be performed. EDF is supposed to have answered this request by what the CNE has characterized as a “clarification by EDF on the management of irradiated fuel” [CNE 97]; but the CNE appears to have published no response in its reports. An article concerning Silva, in the Révue Générale Nucléaire, mentions a possible “’re-enrichment’ in U235 either at Tomsk, in Russia, or at the Urenco d’Almelo factory in the Netherlands” [RGN v-vi.99]. These two centrifugation factories would in fact be adapted to the ‘re-enrichment’ of URT.
Cogéma plans to build a centrifuge enrichment plant, Georges Besse II, at Tricastan. (see Enrichment--Centrifugation) One of the 500,000 SWU "double modules" will be "devoted in principle to enrichment of reprocessed uranium. The plant is expected to begin operation at 5% of capacity in 2007 [NucF xii.22.03].
The FBFC plant at Romans has a production line for fuel for pressurized water reactors that is devoted to URT. However, its capacity is only about 200 tons of uranium per year [RGN v/vi 97].
--revised 22 March 2004
HISTORY OF CONVERSION IN FRANCE
Between 1960 and 1983, the Comurhex plant at Malvési converted 17,500 t of URT in the form of uranyl nitrate from graphite-gas reactor fuel reprocessed at Marcoule [CLES 25.v.93]. Le Bouchet seems to have also converted the uranyl nitrate from graphite gas fuel before its shutdown in 1970. It is probable that the major part that was converted was transformed into metal for reuse in graphite gas fuel, perhaps after the URT had been enriched to the level of natural uranium at Pierrelatte. We do not know the destination of the uranyl nitrate from graphite gas fuel reprocessed at Marcoule after 1983.
The uranyl nitrate from the reprocessing of light water reactor fuel was converted, for the most part at least, at Pierrelatte. Comurhex’s Ateliers pilotes converted about 2000 t of uranium from light water fuel reprocessed at La Hague between 1976 and 1990 [Durand 91], and these installations are still operating. Cogéma’s TU2 workshop likewise converted uranyl nitrate from light water fuel.
A portion of the tonnage that was converted belongs to EDF, but Comurhex also converts uranyl nitrate from abroad. Before 1994, the pilot workshops converted URT from the German Karlsruhe plant. In 1989, the company Urep signed contracts with Tokyo and Kansai Electric Power on the conversion into U308 of uranyl nitrate from La Hague. Other Japanese companies have, it seems, likewise asked for conversion services [NucF 1.v.89].
Since 1974, reprocessing contracts have taken into account the destination of the uranyl nitrate. “The company [for which the fuel is reprocessed] has the option of taking the necessary steps to collect the uranyl nitrate or of asking the reprocesser to transport the uranyl nitrate.” If the company does not have the means, “the reprocesser is authorized, after consulting with the company, to convert the uranyl nitrate into another chemical form at the cost of the company . . . The company retains the right to ask the reprocesser to be responsible for the storage of the uranyl nitrate in the installations of the reprocesser” [Cogéma 78].
In 1995, Cogéma already stored “several thousands of tons” of URT belonging to its clients [NucF.x.95]. Since the foreign clients of Cogéma are not in a hurry to use URT fuel, the stock seems to be destined to increase.
PROSPECTS
In 1995, EDF announced that its “strategy aims to recycle all uranium extracted at the same time as plutonium by reprocessing operations” [SFEN 95]. EDF plans to recycle 850 tons of fuel per year, generating 820 tons of URT [Esteve 94]. Every 820 tons of enriched URT generates 110 tons of lightly enriched uranium and 710 tons of depleted uranium [Coeytaux 00].
In 1986, EDF loaded 8 assemblies (4 pure and 4 diluted) into the Cruas 4 reactor. It has since increased the use of URT, but it presently uses it only at Cruas. In 1999, according to the DSIN, Cruas 3 and 4 had been loaded with this fuel.
The EDF policy to increase the rate of irradiation from fuel is in conflict with the policy for the use of URT. In fact, the higher the rate of irradiation is, the more plutonium will be contaminated, notably by U234 and U236, the uranium produced by reprocessing fuel.
Another outlet for URT, other than its use in the standard fuel for pressurized water reactors, would be to use it in Mox. Mox can be manufactured with URT, but as officials for EDF’s fuel service note, “at present, we do not foresee mixing this uranium, which is really still lightly enriched, with plutonium, because we want to avoid adding on radiation protection problems in the Mox factory” [SFEN 95].
From the economic point of view, the reuse of uranium will be advantageous only if the price of the ore increases significantly. The conversion and manufacture of the fuel cost more for URT than for ordinary uranium. The costs of enrichment are similar because the necessity of super-enriching uranium and of taking protective measures practically wipes out the gain realized from the fact that the URT is richer in U235 than natural uranium [BNFL 94; Castaing 81-82]. (URT is enriched by 3.95% to correspond to standard fuel with uranium at 3.7% in order to balance out the neutron absorption of U234 and U236).
Concerning costs, the Castaing Commission has noted that “the introduction of new data relative to recycling could show that it is preferable to reduce the percentage of U235 in the tails (in the enrichment plant) than to recycle” [Castaing 81-82].
Whether uranium is reused or not, the extraction of uranium from irradiated fuel does not contribute to a better management of waste.
If it is not reused, it has to be stored. U308 is more stable than uranyl nitrate (UO2[NO3]2) but still highly irradiated. At Pierrelatte, Cogema has storage areas for U308 URT with a capacity of around 10,000 tons, or the equivalent of only around five years of TU5 production. Each year between 1995 and 1999, around 1,500 tons of URT came out of La Hague. In 1981-82, the Castaing Commission emphasized that “whatever option is chosen, it will be necessary to study the reprocessed uranium storage conditions and to evaluate the cost of storing this waste”.
The production of standard URE fuel for pressurized water reactors produces radioactive wastes along the whole chain, including depleted uranium coming from the enrichment plants. In fact, in 1996, the CNE asked which wastes would be generated in the case of URT reuse, and in particular, what kind of management was planned for the tons of waste uranium at the level of the enrichment plant associated with this recycling. Would the depleted uranium originating from URT enrichment always remain abroad? [CNE 96].
Toward the end of 2000, WISE-Paris calculated that the reprocessing of UNGG fuel and standard fuel for REP had furnished around 26,550 tons of URT (18,200 tons for France) of which 1565 tons had been sent to an enrichment plant. Of the 1565 tons, 210 tons had been transformed into URE, and had been put into the form of fuel assemblies. The rest was depleted uranium. “The rate of recycling of uranium from irradiated fuel [URT] attributed to France is on the order of 10%,” but “the rate of recycling of uranium contained in French fuel [irradiated, reprocessed or not] scarcely exceeds 5%,” WISE-Paris has indicated [WiseWeb 00].
The final products, Mox fuel or standard fuel for pressurized water reactors, will themselves become official waste finally, since third time use of uranium (if not second time) is of no interest. The Castaing Commission noted that the high level of U236, increased by a factor of 3.2 by enrichment procedures, leads to one-time recycling of uranium, recovered during reprocessing [Castaing, 81-82]. At this time, EDF does not plan to reprocess URE-based fuels [CNE 9]. Although as of May 31, 2001, 17.9t of URE were stored at La Hague.
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