JAEA-Review-2010-065.pdf:15.99MB - 日本原子力研究開発機構

Safety Measures, Utilization Status and Machine Time
Proportion at TIARA Facility
K. Mizuhashi, H. Takizawa, M. Hosono, K. Nishimura,
Y. Nakamura, S. Kaneya, S. Mochizuki, T. Asai, M. Kawabata and K. Daikubara
Department of Advanced Radiation Technology, TARRI, JAEA
1. Safety Measures
Two different periodical inspections for TIARA facilities
were performed every month and every three months to
maintain safety of the facility.
The computer for the radiation safety data management
was renewed in fiscal year 2009. This computer acquires
necessary data for the radiation evaluation: concerning
fourteen radiation monitors, an anemometer, operating
condition of four accelerators, four environmental radiation
monitors and two
safety interlock
systems. In case of
radiation trouble,
appropriate doses of
radiation can be
evaluated from these
data. The computer
for radiation safety
management is shown
in Fig. 1. Whenever
the TIARA facilities
are working, one can
observe radiation dose
in the entire facility
with this computer
system.
Fig. 1 Computer system for
radiation management.
2. Utilization Status
Change of number of visitors for experiment at TIARA
facility as a function of fiscal year is shown in Fig. 2. The
maximum number of visitors was 1,404 in 2005. The
number of visitors in fiscal year decreased from 2006 and it
Number
160
140
120
100
80
60
40
20
0
5-01
Number of researchers (x10)
Number of research subjects
92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09
Fiscal year
Fig. 2 Relations between the numbers of research
visitors and research subjects at TIARA.
JAEA-Review 2010-065
was 781 in 2009. It seems that the decrease of the number
of visitors was related to the amount of the travel expenses
budget that supports the external users. The year when the
budget was the highest was 2002. Afterwards, the budget
was reduced and was not provided at all after 2006.
Regardless of this decrease, the total number of research
subjects in these five years seems to be almost constant at
140 as shown in Fig. 2. The reason for this is that common
use unrelated to travelling expenses increased after 2006.
The decrease in the numbers of research subject and visitor
from the peak was 92.6% and 55.6%, respectively in 2009.
3. Machine Time Proportion
Four accelerators were used for various research subjects
according to operation plan in fiscal year 2009. The
proportion of the machine time used in the fields of research
is shown in Fig. 3. The total of utilization time of the AVF
cyclotron and the electrostatic accelerators in fiscal year
2009 was 2,272 hours and 476 days, respectively which were
offered to the experiments.
The highest proportion at the cyclotron was for the field
of Biotechnology-Medical application, 33.7%. At the
electrostatic accelerators, the highest proportion was for the
field of the Basic technology, 36.8%. The proportion for
the field of RI production-Nuclear science was only 0.4%.
This is because some subjects were moved from the RI
production-Nuclear science field to the Biotechnology-
Medical application fields.
The total proportion of “the common use” and “the
promotion use” was 16.3% at cyclotron and 13.2% at
electrostatic accelerator, respectively. These values were
within 20% of the total machine time which is provided as
“the common use” and “the promotion use” at the TIARA
facility.
Research field
- 179 -
Common use
Promotion use
Materials for space
AVF cyclotron (2272 hours)
Electrostatic accel. (476 days)
Reactor materials
Bio technology &
A
Medical application
Inorganic materials
RI production &
Nuclear science
B
Organic materials
C
&
Radiation chemistry
Basic technology
0 10 20 30 40
Percentage of use rate (%)
Fig. 3 Proportion of the machine time used for the
fields of research.