Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
-ray spectroscopic methodsFurutaka, Kazuyoshi
JNC TN8400 2000-028, 70 Pages, 2000/10
JNC-TN8400-2000-028.pdf:1.71MB
This report describes the study done by the author as a postdoctoral research associate at Japan Nuclear Cycle Development Institute. This report is divided into two parts: improvements in accuracy in determination of thermal neutron capture cross sections, and improvements in accuracy of photo-nuclear absorption cross section measurements using the HHS. (1)In the measurements of thermal neutron capture cross sections using an activation method, accuracies of the final results attained are limited by (1) accuracy of -ray peak detection efficiencies, and (2) accuracies of -ray emission probabilities. In this study; to determine thermal neutron capture cross sections more accurately, the following researches have been done using a newly developed three-dimensional coincidence measurement system: (1)accurate determination of -ray standard sources using a - coincidence method, for precise calibration of -ray peak detection efficiency, and (2) development of a 
- coincidence measurement system using a plastic scintillation detector as a -ray detector, for the determination of -ray emission probabilities of short-lived nuclides, and measurement of -ray emission probabilities of 
Tc nuclide using the coincidence system. (2)To transform radioactive nuclides with small thermal neutron capture cross sections, use of photonuclear absorption reaction has been suggested. In order to transform these nuclides efficiently using the reaction, one has to know detailed behavior of the photo-absorption cross sections. In this study, a Monte-Carlo simulation code has been used to create a standard set of -ray response functions of the high-resolution high-energy spectrometer (HHS), to enable reliable analyses of the data obtained by the spectrometer.
Aoyama, Takafumi; *; Sumino, Kozo; Saikawa, Takuya*
PNC TN9410 98-004, 74 Pages, 1997/12
The Corrosion Product (CP) is the major radiation source in the primary cooling system of an LNFBR plant. It is important to characterize and predict the CP behavior to reduce the personnel exposure dose due to CP deposition. The CP measurement was carried out in the Experimental Fast Reactor JOYO during the 11th annual inspection period when the accumulated reactor thermal power reached about l43GWd. The CP deposition density was measured using a pure germanium detector. The plastic scintillation fiber (PSF) was applied for the gamma-ray dose rate distri bution measurement and compared with the thermoluminescence dosimeter (TLD). The major results obtained by the CP measurements in JOYO are the follows: (1)The major CP nuclides deposited in the primary cooling system are 
Mn and 
CO. Mn is the dominant isotope and it tends to deposit in the cold leg region. On the other hand, Co deposits mainly in the hot leg region. The deposition density of Mn is about seven times as much as that of Co in the cold leg region and twice in the hot leg region. (2)The deposition densities of Mn and Co, and the gamma-dose rate were decreased from the last data in the previous annual inspection period mainly due to the short operation time and the longer cooling time. (3)The continuous gamma-ray dose rate distribution up to 10m can be measured by using the PSF in a few minutes. The PSF is suitable to measure the gamma-ray dose rate distribution in the maintenance work area where it is narrow and the mixture of gamma-ray sources from primary pipings and components. The data base of detailed gamma-ray dose rate distribution was greatly extended by the PSF.
Sumino, Kozo; Aoyama, Takafumi; Emoto, Takehiko
PNC TN9410 96-233, 27 Pages, 1996/08
It is important to accurately evaluate Corrosion Products (CPs) behavior in a FBR plant to reduce the personnel exposure due to CP deposition. A series of measurements of the gamma-ray dose rate distribution has been carried out in the Experimental Fast Reactor JOYO to characterize the CP behavior in the primary coolant system. The Plastic Scintillation Fiber (PSF), which is a position sensitive radiation detector that can detect the radiation dose rate at the relevant position in the fiber, was introduced to upgrade the gamma-ray distribution measurement in JOYO. In order to apply the PSF for the JOYO environment, the specification of the fiber was modified to obtain a wide range of sensitivity from about 0.01mSv/h up to 10mSv/h. This range covers the gamma-ray dose rate in the JOYO primary coolant system. In higher gradients of dose rate distribution than that of the PSF's position resolution, the measured data were unfolded by using the response matrix with a successive approximation method to reproduce the narrow distribution. As a result of the study on PSF, the continuous gamma-ray dose rate distribution was able to be measured by PSF in a few minutes, whereas point data at 1 m intervals were laboriously obtained by a set of Thermo-luminescence Dosimeters (TLDs). It was confirmed that the measurement of CP behavior upgraded significantly by using a detailed gamma-ray dose rate distribution.
Tsujimura, Norio; Momose, Takumaro; Shinohara, Kunihiko
PNC TN8410 96-211, 37 Pages, 1996/07
None
Murakami, Kiyonobu*; *
PNC TJ1500 93-004, 114 Pages, 1993/09
no abstracts in English