Urenco is investigating after a worker at Germany’s Gronau enrichment plant was exposed to uranium hexafluoride.
The incident occurred on 21 January when, during preparation of a container, a release of the radioactive substance occurred. One employee of who was operating at that time was admitted to hospital as a precaution for 24 hours for observation.
The employee involved was exposed to only small traces of uranium and thus the radiological contamination is negligible. In a statement Urenco said that the measure of contamination recorded at a maximum of 1.1mSv, which equates to less than 5% of the legally annual permitted dose (20mSv). The minor levels of uranium initially measured in his urine also significantly declined during the first day.
In addition, the small amount of contamination to the employee’s feet and legs was limited to the clothing. Minor contamination to the hands arose from contact with the clothing, however these were decontamiated immediately following the incident.
The nuclear inspectors, together with independent experts, investigated the incident on location in Gronau (on Monday 26 January 2010). Investigations are continuing however Urenco has issued an interim report confirming that the substance in the container was UF6.
The container involved was a 30B container used for the transport of enriched uranium hexafluoride. These containers are used as multi-use containers and are in transit between the enricher and the fuel assembly manufacturer. The maximum fill quantity is 2.27t UF6. The container is kept at negative pressure. Every five years a pressure test is carried out at 28 bar. In order to do this, the interior must first be cleaned. The container concerned had been delivered to Urenco as “clean and washed out”. Before the pressure test is carried out the containers are inspected in the container preparation area. This also involves an endoscopic inspection of the interior. The chemical release as described above occurred during the preparations for this test.
Meanwhile, Urenco, which operates enrichment plants in the UK, Germany and the Netherlands, has deemed 2009 “another year of strong business performance.” The company also says its fourth enrichment plant in the USA is ready to start commercial operation, subject to receipt of regulatory approval.
According to the interim trading statement released 25 January, Urenco’s net income for 2009 is forecast to be “significantly higher” than in the previous year because of a lower depreciation charge expected following an extension of the useful lifetime assumption of core equipment. In addition, there will be significantly lower net finance costs.
Urenco also said capacity expansion in Europe and the USA progressed well in 2009, with approximately 1200tSW added by year-end, bringing total Group capacity to 12,200tSW/year.
At the firm’s Dutch site in Almelo, Hall 5 was completed and construction began for the installation of Hall 6. In the last quarter of 2009, the Board also approved further expansion at Almelo with extensions to both Halls 5 and 6. Construction at Almelo is expected to begin during the second half 2010. Operations at Separation Hall 2 in Gronau, Germany, began in 2009 following successful receipt of an operating licence.
Modular expansion of the European plants will continue into 2010 and beyond in order to achieve a Group enrichment target of 18,000 tSW/a by 2015, Urenco said.
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