Team:Lyon-INSA-ENS/Project/Industrialization

Industrialization

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During the project development we organized a lot of meetings with nuclear industry actors.

To know more about the operation of nuclear power plants we visited the nuclear power plant of Tricastin and we met a Chemist of the nuclear power plant of Bugey

We also visited the Nuclear center for processing and conditioning low-level radioactive waste (CENTRACO) to learn more about the constraints of nuclear waste processing.

Thanks to our partner Assystem we met nuclear experts who provided us additional and accurate informations on the issues of nuclear industry and assessed feasability of the project.

Why a Cobalt Biofilter in nuclear power plants ?

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1- It is known that a pulse of radioactive Cobalt emission occurs in the primary circuit of water, during the maintenance of nuclear power plants when they open the reactor core. This pulse damages the ion exchange resins used to filter the water and reduce its radioactive level.

2- Major preocupation of nuclear industry is the reduction of waste volume and a previous modelization estimated that the "Cobalt Buster" strain is very efficient :

4 kg of modified bacteria = 8000 kg of ion exchange resins

3- Drastic reduction of the costs of waste processing and conditioning is also a major issue for nuclear industry. Biofilter production is less expensive and the biofilter may prevent damage caused to the resins. It could significantly reduce costs of rehabilitation of primary circuit wastewater.

4- Maintenance phases generate a shortfall of millions of euros and reduction of the duration of maintenance phases represent a major issue.

Mettre ici la video de Margaux sur le prototype de biofiltre

Why not in the primary circuit ? (Experts advice)

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1- Cobalt released during the opening of the nuclear reactor may represent 150 TeraBecquerel (TBq) of radioactivity (500 m3 of contaminated water with a radioactive Cobalt estimated level of 300 gigaBq / m3).

If the Cobalt biofilter is used as shown above, dose rate for only 1 of the 150 TBq will represent 0,4 sievert per hour (Sv/h) whereas the authorized rate is up to 20 mSv per year.

Calculation of dose rate:
Dose Rate = 0.54 * C * E * P / d²

with
C = the activity Curie
E = energy radiation in MeV
P = the percentage of emission
d = distance from the radiation source

To treat 1TBq of Co60 with d = 1m (1TBq = 30 Curie)
EP = 2.5

we can estimate Dose rate
DR = (0.54 * 30 * 2.5) / 1²
DR = 40 rad / h
DR = 0.4 Gy / h
DR = 0.4 Sv / h

This exposure rate supposed that if we want to use our "Cobalt Buster" biolfilter, a concrete wall of at least one meter has to be built for each parallel biofilter, and every manipulation has to be automated. Besides, in this circuit, Cobalt could exist not only in an ionic form, but also exist in its elemental form, and we are unsure if our bacteria would recognize it.