(November 2, 1998) After it was revealed that many spent fuel casks and rail cars were contaminated far above the international limit of 4 Becquerel/cm2, transports in France were cancelled in May. Already on July 6, the transport resumed, without direct dose measures being carried out by official authorities.
(501.4941) WISE Amsterdam - On September 16, the French radiation protection authorities OPRI and IPSN finally carried out their own measurements to evaluate external doses received by railway personnel working with or near nuclear spent fuel transports at Valognes terminal, close to Cogema's La Hague reprocessing plant. Cogema had measured personnel exposure for years, but this was the first time ever that government agencies did so. OPRI alone also did two sets of measurements at another important railway terminal at Villeneuves-St. Georges near Paris. In the first measurement, OPRI found doses of 0.15 to 25 microsievert per hour. Depending on exposure time, those doses could put railworkers above the annual public limit, which is now 5 millisievert (mSv) but will soon be 1 mSv. Exposure for 45 hours a year to 25 microSv would suffice. (one millisievert is 1000 microsievert). The south-rail trade union has asked to provide radiation counters for all switching stations. It was also proposed to equip all railway personnel, liable to work near spent fuel transports, with personal dosimeters. That would make them more aware of the risks and would give an idea of their real doses either under normal conditions or during emergencies.
OPRI said more work is needed to understand the behavior of rail workers and to make appropriate dosimetry models. The nuclear safety agency DSIN made it a condition for resumption of spent fuel transports, to equip all railway personnel at Valognes with personal film badges.
The French independent organization Crii-Rad already carried out measurements at the Bugey nuclear reactor in June. EdF officials refused to let Crii-Rad take measurements at the Bugey site, but the national railway company SNCF made it possible for Crii-Rad to take measurements at the Bugey switching station. Crii-Rad found gamma and neutron dose levels of 129 microSv/hr, compared with a background dose level of 0.15 microSv/hr. They also controlled doses from casks with uranium hexafluoride, discovering high doses there too: from 13 to 20 microSv/hr. When asked, DSIN and OPRI officials qualified the doses as "unprobable" and declared that in any way the doses were below the official dose limits.
More incidents
Since the resumption of French spent fuel transports, two incidents of excess contamination took place. From July 6 to the end of September 21, spent fuel transports left 12 reactor sites. The first contamination case was a truck with spent fuel from Flamanville to La Hague's reprocessing plant. The cask had been waiting for several months and so escaped the high-pressure jet cleaning which is now applied to all transports by Cogema. Four points were above the norm, the highest at 15 Bq/cm2. The second contaminated cask transported by rail came from Belleville and registered three points above the 4 Bq/cm2 limit with a maximum of 31 Bq/cm2. One point on the rail car measured 74 Bq/cm2.
A truck with five drums of low- and medium-level reactor waste from Chinon to Andra's low-level storage at Soulaines also registered above the limit. At a two-meter distance, a dose rate of 0.12-0.15 milliSv/hr was measured while the limit is 0.1 microSv/hr. The EdF said the incident was caused by improper loading of the truck. DSIN officials said this incident was "more serious" in its nature than the spent fuel contamination incidents.
Source:
- Nuclear Fuel, 21 September 1998
- Nucleonics Week, 1 October 1998
- Crii-Rad Press Communique, 16 September 1998
- Le Monde, 7 July 1998
Contact: Crii-Rad, 471 avenue V.Hugo
26000 Valence, France.
Tel: +33-475-418 251; Fax: +33-475-812 648