III.A. Gaseous Effluents

Marcoule is authorized to release each year 60,000 TBq of gases other than tritium, 10,000 TBq of tritium, 150 GBq of the halogens (essentially iodine 129), 80 GBq of aerosols, and 400 MBq of alpha emitters.

In 1997, it released 5.7 PBq of rare gases, 15 GBq of halogens, 0.54 GBq of aerosols, 790 TBq of tritium and 7.2 MBq of alpha emitters, according to monitoring by Cogéma [HC 98, Fig. 5]. These figures represent a decrease. Figures from 1988 to 1997 show that the peak year for halogens during that period was 1990 (80 GBq), for aerosols, 1989 (17 GBq), for tritium 1988 (1190 TBq), for alpha 1996 (25 MBq). The figures for rare gases prior to 1994 are covered by defense secrecy, but in 1996 they reached 16 PBq. It is not clear whether the figures include any accidental releases.

The report of the Groupe de Travail sur la Contamination Radioactive et Chimique des Sites INBS (GTC) does not mention earlier years. Certain large accidental releases in the past are known from other sources, for instance 26,000 Ci of tritium, 9 juin 1976, and 18,000 Ci of tritium, 23 October 1981 [CDRPC 94].

The authorized limits for liquid releases from Marcoule each year are 2,500 TBq of tritium, 150 GBq of alpha, 6 TBq of cesium 137, and 6 TBq of strontium 90. The total activity, except for tritium, cesium, and strontium, is limited to 150 TBq a year. Added volumetric activity in the Rhône after dilution by the Rhône cannot exceed certain limits, and releases can only be made when the Rhône is flowing at a rate of between 400 and 4000 m3/s.

Following an agreement with Opri in the eighties, Cogéma has aimed to keep releases below 35% of the radioactivity authorized. As of 1997, annual realeases were 300 TBq of tritium, about 6 TBq of beta activity (apart from strontium 90 and cesium 137) 0.3 TBq of strontium 90, 0.2 TBq of cesium 137, and 10 GBq of alpha, according to Cogéma. These figures represent a decrease by a factor of ten, except for tritium, since 1988 [HC 98]. The releases in 1999, still according to Cogéma, amounted to 24.5 TBq of tritium; 0.62 TBq of radioelements other than tritium, cesium 137, and strontium 90, 0.15 TBq of strontium 90, 0.05 TBq of cesium 137; and 2.88 GBq of alpha emitters [CLIGard vi.27.00].