Distribution of residual long-lived radioactivity in the inner concrete walls of a compact medical cyclotron vault room

Nohtomi, Akihiro; Baba, Shingo; Sasaki, Masayuki; Komiya, Isao; Umedzu, Yoshiyuki; Honda, Hiroshi

doi:10.1007/s12149-014-0918-6

Cited by 15 publications

(21 citation statements)

References 20 publications

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“…Komiya et al. measured radioactivation of concrete cores at a depth of 10 cm, and found radioactivation in the floor, but not in the walls and ceiling around a cyclotron despite a longer duration of operation, more radionuclide production [ 18 O(p, n) 18 F, 46.6 hr/yr; 14 N(d, n) 15 O, 88.5 hr/yr], and a shorter cooling period (28 months) than the cyclotron described herein (Table ). They did not explain or discuss the absence of nonradioactivation in the four walls and ceiling or analyze the composition of the concrete.…”

Section: Discussionmentioning

confidence: 60%

“…The radionuclides of short half‐lives such as 46 Sc and 54 Mn were decayed to become less than the detection limit in measurement during the cooling period . The calculated radioactivity concentration in north and east concrete cores were larger than others because these cores were nearer the target.…”

Section: Discussionmentioning

confidence: 97%

“…Some studies have evaluated the concentrations of neutron‐induced radionuclides in the concrete vault of a cyclotron room; Table . Radionuclides were identified and quantified using a simulation method and neutron flux . Martínez‐Serrano et al.…”

Section: Introductionmentioning

confidence: 99%

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Pre‐discard estimation of radioactivated materials in positron emission tomography cyclotron systems and concrete walls of a cyclotron vault

Wagatsuma

Ishiwata

Nobuhara³

et al. 2019

Medical Physics

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Purpose The concrete vault, cyclotron body, and peripheral equipment in a cyclotron room become radioactivated by neutrons generated by operating an unshielded cyclotron. Radionuclides and the amounts of radioactivated materials must be identified before discarding a cyclotron system. The present study aimed to reduce the amounts of concrete from cyclotron vaults, as well as cyclotron components and peripheral equipment, that will be disposed of as radioactivated waste by clarifying the nature and quantity of radioactivated materials remaining in facilities after cyclotron operations have ceased. Methods Cylindrical concrete cores were bored into all four walls, ceiling, and floor of a room where a Cypris 370 cyclotron had been operated for 22.8 yr and then cooled for 40 months. The accelerated particles comprised protons and deuterons with constant energy of 18 and 10 MeV, respectively. The types and amounts of radionuclides in these cores, in 38 components of the cyclotron including the yoke, and in 13 pieces of equipment in the room, were determined by γ‐ray spectrometry. Concentrations of radioactivity were also calculated using an updated version of Particle and Heavy Ion Transport System and DCHAIN‐SP. Amounts of materials with both measured and calculated total radioactivity concentration (ΣD) of <0.1 Bq/g were identified as being nonradioactivated. Results The major radionuclides in the concrete were 60Co and 152Eu. The radioactivated concrete was distributed to a depth of <38 cm. Most cyclotron components and equipment were radioactivated by neutrons. The major radionuclides in cyclotron components and equipment were 54Mn, 60Co, and 65Zn. A 33% volume of the yoke was regarded as nonradioactivated. Conclusions The estimated amount of radioactivated waste in the concrete was about 70,000 kg (12.5% of the total concrete). Most components of the cyclotron except for the 33% volume of the yoke (20% of the cyclotron body), as well as most peripheral equipment in the room, were radioactivated. Part‐by‐part assessments of radioactive materials using measurements and calculations could distinguish nonradioactive from radioactive materials before they are discarded.

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Section: Discussionmentioning

confidence: 60%

Section: Discussionmentioning

confidence: 97%

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Pre‐discard estimation of radioactivated materials in positron emission tomography cyclotron systems and concrete walls of a cyclotron vault

Wagatsuma

Ishiwata

Nobuhara³

et al. 2019

Medical Physics

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“…While Trnkova et al [8] only identified Bi-204 in the wall of their cyclotron vault apart from a few naturally occurring radionuclides, Yamaguchi and co-workers [9] detected more neutron-induced radionuclides in their wall of interest such as Sc-46, Co-60, Zn-65, Cs-134, Eu-152, Na-22, Mn-54, and possibly Eu-154. Nevertheless, only two pronounced radionuclides, Co-60 and Eu-152, were detected by Fujibuchi et al [10].…”

mentioning

confidence: 95%

“…However, most experimental research has been on the depth distribution of the suspected radionuclides [8][9][10]. While Trnkova et al [8] only identified Bi-204 in the wall of their cyclotron vault apart from a few naturally occurring radionuclides, Yamaguchi and co-workers [9] detected more neutron-induced radionuclides in their wall of interest such as Sc-46, Co-60, Zn-65, Cs-134, Eu-152, Na-22, Mn-54, and possibly Eu-154.…”

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confidence: 99%

Identification and Angular Distribution of Residual Radionuclides Detected on the Wall of BATAN’s Cyclotron Cave

2016

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Detection and measurement of radiation sources around BATAN's cyclotron facilities in Serpong are required as an early step to avoid radiation impacts on the radiation employees who work with the cyclotron. In this paper, radiation emitted from the wall of the CS-30 cyclotron cave are detected and measured using an NaI(Tl) detector coupled with a pocket multichannel analyzer (MCA) at a counting time of 30 minutes for each sampling point on the wall. The sampling points were in the directions of within ±150 o with respect to the incoming proton beams, and the measurements were conducted at heights between 1.2 m and 1.8 m off the floor for every sampling point. The experimental results indicate that Co-60 and Cs-134 detected on the cyclotron cave wall are major radionuclides that contribute to the emitted gamma radiation. The distribution of the gamma ray intensities given off by Co-60 and Cs-134 depend on the angle and position of the sampling points. In general the highest gamma ray rates can be found in the area around 0 o relative to the incoming proton beams. In addition, no other radioactive sources are significantly detected on the wall. The maximum exposure measured on the wall surface was much less than the permissible occupational exposure for radiation workers and general public.

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Characterization and radioactive evaluation of the concrete from a radiotherapy bunker

Torres‐González

Mantero

Hurtado

et al. 2022

Structural Concrete

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The construction of concrete structures for radiological protection in sanitary facilities requires a series of constructive conditions that guarantee safety. The influence of the correct bunkers design, wall thicknesses and the type of materials used is essential to ensure effective protection. The use of barite aggregate concrete is a common resource to improve the radiation attenuation capacity of concrete walls. The present study analyses the structure of a bunker during a renovation work, studying the construction characteristics of the chamber, the state of its elements, the characterization of materials, the identification of the emissions of the possible isotopes present, beta radioactive contamination and the measurement of equivalent dose rates at different points in the concrete. The results made it possible to determine the use of conventional concrete and barite concrete, the latter presenting a BaO content of around 40% and particularly low resistance values, not observing alteration processes in the materials.

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Distribution of residual long-lived radioactivity in the inner concrete walls of a compact medical cyclotron vault room

Abstract: The radioactivity concentration of the inner concrete wall of the medical cyclotron vault room was not uniform. The areas exceeding the clearance level were in the vicinity of the target, but most of the building did not exceed the clearance levels.

Cited by 15 publications

References 20 publications

Pre‐discard estimation of radioactivated materials in positron emission tomography cyclotron systems and concrete walls of a cyclotron vault

Pre‐discard estimation of radioactivated materials in positron emission tomography cyclotron systems and concrete walls of a cyclotron vault

Identification and Angular Distribution of Residual Radionuclides Detected on the Wall of BATAN’s Cyclotron Cave

Characterization and radioactive evaluation of the concrete from a radiotherapy bunker

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