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Environmental monitoring

Environmental testing: sampling water from a well

The MELOX plant continuously measures the impact of its activity on the environment. Aside from the inspections carried out by CEA Marcoule on the ecosystem, liquid and gaseous wastes are subject to close monitoring.

Ongoing environmental monitoring

To evaluate the actual impact of the MELOX site's activities on the environment, nuclear operators make use of specialized and joint services for site operators of the French Atomic Energy Commission (CEA) Facility in Marcoule, which conducts routine monitoring campaigns, enabling:

  • Measurement of the general impact of the site on aquatic and land ecosystems,
  • Detection of any accumulations of radioactive materials caused by prevailing winds (land environments) or current (zones of slow current in river environments).

This monitoring is performed as per the following modalities:

  • Atmospheric monitoring is performed from four regulatory stations located in Codolet, Bagnols-sur-Cèze, Saint-Etienne-des-Sorts (Gard) and Caderousse (Vaucluse), a meteorological station connected to the network Météo France.
  • The level of radioactivity in the land environment is monitored in particular through the analysis of samples of plant life and agricultural products.
  • The water table of Marcoule is also tested through samples taken through targeted drilling. With respect to the MELOX zone, the results of radiological measurements carried out on a monthly and quarterly basis confirm the absence of any incidence associated with the activities of the plant.
  • The level of radioactivity in the river environment (water from the Rhône, aquatic fauna and flora, sediment) is also monitored.

All of the environmental monitoring of the Marcoule site is available in a monthly report published by the French Atomic Energy Commission on their website.

Management of gaseous wastes

Radioactive gaseous discharge

Gaseous discharge form the two nuclear buildings originate from the ventilation of the glove boxes and the facilities. These are released into the atmosphere after three stages of high efficiency filtration. This discharge is released from two chimneys located on the nuclear buildings. Before discharge, the wastes undergo several tests using two systems of filters and alarms located in the chimneys:

  • The measurements of radioactivity, doubled and performed continuously, are logged and monitored on an ongoing basis at the general monitoring station of MELOX and the office of Radiological and Environmental Protection of Marcoule.
  • The samples from filters, doubled and continuous, make it possible to establish a precise radiological report of the wastes.
  • The chemical substance associated with radioactive nuclides are tested.
  • Output measurements are also performed redundantly.

Radioactive gaseous wastes and associated chemical substances (metals dusts, sulfur dioxide, hydrochloric acid, hydrocyanic acid, nitrogen oxide, carbon monoxide) are much lower than the permissible limits. To date the value of measured data pertaining to MELOX activity is 100,000 times lower than the public exposure limits of 1mSv.

The results of these measurements are distributed locally:

  • Read the monthly environmental newsletter on the CEA website
  • Read the information report  (only in french, pdf, 2,8Mo) on nuclear safety and radiation protection 2010 for the establishment of AREVA MELOX.

Conventional gaseous wastes

For its own needs or to ensure the redundancies necessary for the security and safety of the INB, the MELOX facility has the following installations:

  • Two fuel oil burners (1.85 MW) to produce hot water to heat the buildings,
  • Two emergency diesel generator set and two backup diesel generator sets.

Combustion gas is discharged through chimneys specific to each system. Boiler discharge is periodically tested.

The values measured (nitrogen oxide, dust, velocity) are below regulatory levels. Given the occasional nature for use in domestic fuel, the diesel generator sets are not subject to routine inspection.

Procedures for testing liquid wastes

A distinction is made between two types of liquid waste: radioactive wastes, which originate from the implementation of the industrial process, and conventional wastes, such as rain water, sewage (sanitary), and wastewater.

Radioactive liquid waste

The AREVA MELOX plant, being a dry plant (limitation on the use of water in its facilities), the few liquid wastes produced are essentially generated by tests and analyses carried out by the quality control lab of the plant. They are low- or mid-level activity, and are systematically tested before being sent to the Liquid Waste Treatment Station (LWTS) in Marcoule for treatment and testing before discharge into the Rhône or rerouting towards the corresponding disposal reactor.

To date the value of the data measured pertaining to the activity of MELOX are 100,000 times below the public exposure limits of 1mSv.

Conventional liquid waste

These wastes originate from sewage and wastewater (sanitary) networks that are treated and tested by MELOX purification plants. They also originate from the rainwater network as well.

After treatment by the purification plants and before discharge into the counter-canal, the physical and chemical quality of the conventional liquid wastes are checked.

All of these conventional liquid wastes are nonetheless subject to regulatory radiological testing before discharge into one of the tributaries of the Rhône, and then into the Rhône itself.

These tests are performed by the laboratory of the Radiological and Environmental Protection department of the French Atomic Energy Commission in Marcoule.

To date no contamination has been observed.

In addition, following application of the prefectoral order of June 14, 1994, this same laboratory carried out the radiological and chemical tests in the counter-canal, after mixture with conventional wastes originating from the entire Marcoule site.

The results of these measurements are distributed locally:

  • Read the monthly environmental newsletter on the CEA website