The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform

Yasuhiro Yamaguchi - One of the best experts on this subject based on the ideXlab platform.

Shuichi Tsuda - One of the best experts on this subject based on the ideXlab platform.

Akira Endo - One of the best experts on this subject based on the ideXlab platform.

  • Impact of the introduction of ICRP Publication 103 on Neutron Dosimetry.
    Radiation protection dosimetry, 2011
    Co-Authors: Tatsuhiko Sato, Akira Endo, Hiroshi Yasuda, Koji Niita
    Abstract:

    The impact of the introduction of ICRP Publication 103 on Neutron Dosimetry was analysed by calculating effective doses in various operational Neutron fields, using dose conversion coefficients derived from the recommendations given in ICRP 103 and ICRP 60. It was found from the analysis that effective doses based on ICRP 103 are generally smaller than those based on ICRP 60, mainly owing to the revision of w(R) assigned to Neutrons. The results also indicate that H*(10) can provide a conservative estimate for ICRP 103-based effective doses in most Neutron fields. These tendencies suggest that the radiological protection system currently adopted in accelerators and nuclear facilities can be maintained after the introduction of ICRP 103, with respect to Neutron Dosimetry.

  • Development of Three Kinds of Tissue Substitutes for a Physical Phantom in Neutron Dosimetry
    Journal of Nuclear Science and Technology, 2005
    Co-Authors: Shuichi Tsuda, Akira Endo, Yasuhiro Yamaguchi
    Abstract:

    Three kinds of tissue substitutes were synthesized in order to develop a physical phantom for Neutron Dosimetry. The optimal elemental compositions and densities were determined using a Monte Carlo simulation method, based on absorbed dose distributions of Neutrons of a few MeV in various materials. The characteristics of the synthesized tissue substitutes were verified by absorbed dose measurements using monoenergetic Neutron sources and a 252Cf Neutron source. It was found that the developed tissue substitutes, NAN-, HAI- and HONE-JAERI, have tissue equivalence to actual tissues within an accuracy of 10% for Neutrons in most of the common fast Neutron fields.

  • Energy Dependence of Absorbed Dose Distributions In a Soft Tissue Substitute for Neutron Dosimetry
    Journal of Nuclear Science and Technology, 2004
    Co-Authors: Shuichi Tsuda, Akira Endo, Yasuhiro Yamaguchi
    Abstract:

    In order to develop a physical phantom for Neutron Dosimetry, a soft-tissue substitute improved in hydrogen and oxygen contents was synthesized. Absorbed dose distributions in the synthesized tissue substitute were measured using monoenergetic Neutrons (0.556 and 5 MeV) and quasi-monoenergetic Neutrons (40 and 65 MeV). It was found that the tissue substitute has soft-tissue characteristics in terms of the absorbed dose distribution, in the energy range from several MeV up to 100 MeV.

Choon Sung Yoo - One of the best experts on this subject based on the ideXlab platform.

  • In-Vessel and Ex-Vessel Neutron Dosimetry Programs in Korea
    EPJ Web of Conferences, 2016
    Co-Authors: Choon Sung Yoo, Byoung Chul Kim, Arnold H. Fero, Stanwood L. Anderson
    Abstract:

    In Korea, 20 PWRs are operating and 4 more PWRs are under construction. The in-vessel Neutron Dosimetry programs have been designed and implemented since each plant began operation. In addition to the in-vessel Dosimetry program, ex-vessel Neutron Dosimetry systems have been installed for 16 PWRs. The objective of this paper is to describe the in-vessel and ex-vessel Neutron Dosimetry program of the PWRs in Korea and to compare in-vessel and ex-vessel Dosimetry evaluation results. For this purpose plant and cycle specific forward Neutron transport calculations and Dosimetry measurement evaluations were carried out according to Regulatory Guide 1.190. Comparisons between the calculations and measurements were also performed for the reaction rates of each Dosimetry sensor and the results show good agreement.

  • Fast Neutron Exposure Evaluation Using the Ex-vessel Neutron Dosimetry System
    Journal of Nuclear Science and Technology, 2008
    Co-Authors: Choon Sung Yoo, Jong-ho Park
    Abstract:

    The Code of Federal Regulations, Title 10, Part 50, Appendix H, requires that the Neutron Dosimetry be present to monitor the reactor vessel throughout its plant life. The Ex-Vessel Neutron Dosimetry Systems which consist of sensor sets, radiometric monitors, gradient chains, and support hardware have been installed for Korean nuclear power plants after a complete withdrawal of all six in-vessel surveillance capsules. The systems have been installed in the reactor cavity annulus in order to characterize the Neutron energy spectrum variations axially and azimuthally over the beltline region of the reactor vessel. In addition, stainless steel gradient chains are used in conjunction with the encapsulated dosimeters to complete the mapping of the Neutron environment between the discrete locations chosen for spectrum determinations. Cycle specific Neutron transport calculations were performed to obtain the energy dependent Neutron flux throughout the reactor geometry including the Dosimetry positions. Comparis...

  • Monitoring of a Radiation Embrittlement by a Reliable Fluence Evaluation With a Neutron Dosimetry in a Reactor Pressure Vessel
    Volume 7: Operations Applications and Components, 2006
    Co-Authors: Sam-lai Lee, Choon Sung Yoo, Byoung Chul Kim, Kee-ok Chang
    Abstract:

    The assurance of a nuclear reactor pressure vessel integrity plays an important role in achieving a safety and extending the life of nuclear power plants. In the assessment of the state of an embrittlement of a pressure vessel in a pressurized light water reactor, an accurate evaluation of the Neutron exposure of each of the materials comprising the beltline region of the vessel is required. The evaluation is performed through a Neutron Dosimetry analysis where a fluence calculation is done by both measurement of the dosimeter materials removed from surveillance capsules and a Neutron transport calculation. Now that all the capsules have been completely removed from the reactor vessel and analyzed by a periodic monitoring schedule, four ex-vessel sensor sets are installed as a substitute capsule in an axial direction in the reactor cavity and then removed for an analysis in order to meet the regulation requirements. The results showed that the differences between the measurements and calculations are less than 20% for each capsule, which means these analyses satisfy the acceptable criterion required by Regulatory Guide 1.190, and they also provide an assurance that such an evaluation including an ex-vessel Neutron Dosimetry can be used to predict the fluence of a nuclear reactor vessel with a good reliability.© 2006 ASME

Frank H. Ruddy - One of the best experts on this subject based on the ideXlab platform.

  • Advances in high fluence solid state track recorder Neutron Dosimetry
    International Journal of Radiation Applications and Instrumentation. Part D. Nuclear Tracks and Radiation Measurements, 1991
    Co-Authors: Frank H. Ruddy
    Abstract:

    Abstract Neutron dosimeters based on measurements of Neutron-induced fission rates with solid state track recorders (SSTRs) provide a versatile and accurate method for reactor Dosimetry applications. The high fluence upper limit of the range of the SSTR Neutron Dosimetry method is determined by track counting limitations at very high track densities. The recent development of techniques for the preparation and calibration of ultra low-mass fissionable deposits has extended the high-fluence limit to about 5×1018 Neutrons/cm2. To date, more than 900 SSTR Neutron dosimeters have been exposed in high Neutron fluence applications at commercial nuclear power reactors. At the same time, parallel efforts have been carried out to further extend the range of the SSTR Neutron Dosimetry technique, to improve the precision of the present methods, and to verify the high accuracy of the method through controlled exposures in standard Neutron fields. The present status of high fluence SSTR Neutron Dosimetry techniques as well as recent improvements in the method will be discussed.