Calculation of Activated Water Radiation Maps in ITER
- Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France)
ITER is a nuclear machine designed for 500 MW DT fusion power emitting an immense power in the form of 14 MeV neutrons (∼400 MW). These high energy neutrons activate the water used to cool the first wall, blanket modules, vacuum vessel etc. The principal isotopes generated in water coolant are {sup 16}N and {sup 17}'N from oxygen isotopes. Both these radioisotopes are generated by neutrons having energy more than 10 MeV. Even though these isotopes are short-lived (T{sub 1/2} {sup 16}N: 7.13 s and T{sub 1/2} {sup 17}N: 4.17 s) they generate significant radiation fields outside the bio-shield due to high neutron fluence at irradiation end, large volume of the coolant, high speed of the coolant, emission of high energy nuclear radiations from {sup 16}N (gammas) and {sup 17}N (neutrons). Therefore, radiation fields generated by the activated water need to be calculated in order to design the plant systems to withstand radiation dosage and for the safety of the workers as per regulatory limits. This paper presents the calculation methodology of the {sup 16}N and {sup 17}N sources in the coolant lines, manifolds, heat exchangers etc., which are distributed over the wide area outside the bio-shield. The calculated source is modelled in the MCNP building model which is approximately 120 m x 80 m x 50 m. The building model has significant amount of shielding walls (∼3 m thickness). This presents a challenge to get the sufficient statistics everywhere in the global model. The radiation transport is performed with the code MCNP to calculate the radiation fields (biological dose rate, absorbed dose in silicon, 1 MeV silicon equivalent fluence, neutron flux) throughout the tokamak complex.
- OSTI ID:
- 23047398
- Journal Information:
- Transactions of the American Nuclear Society, Vol. 116; Conference: 2017 Annual Meeting of the American Nuclear Society, San Francisco, CA (United States), 11-15 Jun 2017; Other Information: Country of input: France; 1 ref.; available from American Nuclear Society - ANS, 555 North Kensington Avenue, La Grange Park, IL 60526 (US); ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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