In the frame of the International Fusion Materials Irradiation Facility (IFMIF) project the ENEA-Bologna group was committed (Task No. TW5-TTMI-004 Deliverable 7) to perform the evaluation of activation, inventories and dose rates induced by deuterons and neutrons in the cooling system and atmosphere hall of the Accelerator Facility. In the present report the results of dose rate estimates around the HEBT (High Energy beam Transport) and the scraper device are given. For the beam-off dose rates two different zones have to be considered: in the first one, about 10 m nearest to the DTL, the dose rate, due to deuteron beam losses of 58nA/m, is about 100 μSv/h at 1 week cooling time and at 1 m from the surface( this area can be classified as a Restricted access zone for maintenance, with specific procedures for worker protection);in the second one, nearest to the Test Cell, the most important contribution is due to back neutrons activation. The total beam-off dose rates is higher than 1mSv/h up to one year. This area has to be classified as an Access Prohibited zone, requiring local shielding criteria. The same is also for the area around the scraper device. The total beam-off dose rates due to the activation of corrosion products in DTL water cooling system are lower than 10 μSv/h at 1 hour cooling time. The area around the water cooling pipes can be classified as Frequent Access zone.
M. Frisoni, D.G. Cepraga, G. Cambi (2007). Evaluation of activation, inventories and dose rates induced by deuterons and neutrons in the cooling system and atmosphere hall of the Accelerator Facility. FRASCATI (ROMA) : ENEA.
Evaluation of activation, inventories and dose rates induced by deuterons and neutrons in the cooling system and atmosphere hall of the Accelerator Facility
CAMBI, GILIO
2007
Abstract
In the frame of the International Fusion Materials Irradiation Facility (IFMIF) project the ENEA-Bologna group was committed (Task No. TW5-TTMI-004 Deliverable 7) to perform the evaluation of activation, inventories and dose rates induced by deuterons and neutrons in the cooling system and atmosphere hall of the Accelerator Facility. In the present report the results of dose rate estimates around the HEBT (High Energy beam Transport) and the scraper device are given. For the beam-off dose rates two different zones have to be considered: in the first one, about 10 m nearest to the DTL, the dose rate, due to deuteron beam losses of 58nA/m, is about 100 μSv/h at 1 week cooling time and at 1 m from the surface( this area can be classified as a Restricted access zone for maintenance, with specific procedures for worker protection);in the second one, nearest to the Test Cell, the most important contribution is due to back neutrons activation. The total beam-off dose rates is higher than 1mSv/h up to one year. This area has to be classified as an Access Prohibited zone, requiring local shielding criteria. The same is also for the area around the scraper device. The total beam-off dose rates due to the activation of corrosion products in DTL water cooling system are lower than 10 μSv/h at 1 hour cooling time. The area around the water cooling pipes can be classified as Frequent Access zone.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
