Simulating the neutron-induced activity and dose rate of components in the reactor pressure vessel of Oskarshamn 3
(2024) PHYM01 20241Particle and nuclear physics
Department of Physics
- Abstract
- During operation of a nuclear power plant the neutron radiation of the reactor core may induce activity in surrounding components and equipment. These may in turn become radiation hazards during decommissioning or component exchanges. To better plan for this, models of the degree of activation and subsequently, the dose are therefore of great importance. Building upon a previous study of the neutron flux around the reactor core of Oskarshamn 3, the induced activity was determined with FISPACT in 2 components above the reactor core; the steam separator and the steam dryer. These were chosen since their activation had not previously been studied in detail. The activity is simulated for 5 different cool-down times; 3 days, 1 year, 30 years,... (More)
- During operation of a nuclear power plant the neutron radiation of the reactor core may induce activity in surrounding components and equipment. These may in turn become radiation hazards during decommissioning or component exchanges. To better plan for this, models of the degree of activation and subsequently, the dose are therefore of great importance. Building upon a previous study of the neutron flux around the reactor core of Oskarshamn 3, the induced activity was determined with FISPACT in 2 components above the reactor core; the steam separator and the steam dryer. These were chosen since their activation had not previously been studied in detail. The activity is simulated for 5 different cool-down times; 3 days, 1 year, 30 years, 100 years and 1000 years. Using the activity, the surface dose rate and the dose rate 1 m in air from the components is simulated in MicroShield. Due to limitations in the software, 3 simplified geometries were used, one which overestimated the dose rate, one which underestimated it and one which laid in between. The surface dose rate was highest in the steam separator and was at most 225/6.5/140 mSv/hour for the respective geometries, and the dose rate at a 1 m distance was at most 13.6/2.9/18.3 mSv/hour. The dose rate from the steam dryer was only above 0.1 mSv/hour at the surface of the component 3 days after irradiation, and was for the most part below 10 μSv/hour. (Less)
- Popular Abstract
- During the operation of a nuclear power plant materials and components in close proximity to the reactor core may become radioactive. This will of course have consequences for the safety of personnel during handling and disposal of radioactive waste when components are exchanged, and in the long run when the facility is decommissioned and dismantled. To better be able to plan and manage these activities, greater knowledge of the degree of radioactivity is necessary. Previous studies on the subject have been made for the reactor Oskarshamn 3 (O3) located in the municipality of Oskarshamn on the Swedish east coast, but the aim of this paper was to do so in greater detail, and to gain new insight. For that purpose, two components were chosen... (More)
- During the operation of a nuclear power plant materials and components in close proximity to the reactor core may become radioactive. This will of course have consequences for the safety of personnel during handling and disposal of radioactive waste when components are exchanged, and in the long run when the facility is decommissioned and dismantled. To better be able to plan and manage these activities, greater knowledge of the degree of radioactivity is necessary. Previous studies on the subject have been made for the reactor Oskarshamn 3 (O3) located in the municipality of Oskarshamn on the Swedish east coast, but the aim of this paper was to do so in greater detail, and to gain new insight. For that purpose, two components were chosen for the analysis which had previously not been studied in detail; the steam separator and the steam dryer, located inside the reactor of O3. The results from a previous study of the radiation around the reactor core, along with material data of the components in question, was then used to simulate the degree of radioactivity at the surface of the components, as well as at a 1 m distance. The results showed that the degree of radioactivity was in fact significant in some parts of the steam separator which was located closer to the reactor core. For the first year after the reactor had stopped its operation, a worker would not be able to spend more than a few hours close to the component before reaching their yearly radiation limit. The radioactivity was still significant after 30 years, though not nearly as bad. The steam dryer was however for the most part at a safe level. These results could prove important when the decommissioning of O3 is being planned, as they show that certain measures should be taken regarding the steam separator. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9167531
- author
- Brandt, Simon LU
- supervisor
- organization
- course
- PHYM01 20241
- year
- 2024
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Nuclear power, physics, radiation, radioactivity, dose
- language
- English
- id
- 9167531
- date added to LUP
- 2024-06-24 12:16:33
- date last changed
- 2024-06-24 12:16:33
@misc{9167531,
abstract = {{During operation of a nuclear power plant the neutron radiation of the reactor core may induce activity in surrounding components and equipment. These may in turn become radiation hazards during decommissioning or component exchanges. To better plan for this, models of the degree of activation and subsequently, the dose are therefore of great importance. Building upon a previous study of the neutron flux around the reactor core of Oskarshamn 3, the induced activity was determined with FISPACT in 2 components above the reactor core; the steam separator and the steam dryer. These were chosen since their activation had not previously been studied in detail. The activity is simulated for 5 different cool-down times; 3 days, 1 year, 30 years, 100 years and 1000 years. Using the activity, the surface dose rate and the dose rate 1 m in air from the components is simulated in MicroShield. Due to limitations in the software, 3 simplified geometries were used, one which overestimated the dose rate, one which underestimated it and one which laid in between. The surface dose rate was highest in the steam separator and was at most 225/6.5/140 mSv/hour for the respective geometries, and the dose rate at a 1 m distance was at most 13.6/2.9/18.3 mSv/hour. The dose rate from the steam dryer was only above 0.1 mSv/hour at the surface of the component 3 days after irradiation, and was for the most part below 10 μSv/hour.}},
author = {{Brandt, Simon}},
language = {{eng}},
note = {{Student Paper}},
title = {{Simulating the neutron-induced activity and dose rate of components in the reactor pressure vessel of Oskarshamn 3}},
year = {{2024}},
}