MAIN ACTIVITIES AND ACHIEVEMENTS IN R&D

1. Dalat Research Reactor is a light water moderated and cooled, pool- type reactor using 19.75% enriched UO2-Al dispersion fuel. Its maximum thermal power is 500 kW. The DRR is used for radioisotope production, neutron activation analysis, fundamental and applied researches, and manpower training. By the end of 2018, the DRR had been safely operated and effectively exploited for a total operation time of about 46,000 hrs and with an accumulative released energy of about 860 MWh.

During the past ten years, some reactor technological systems were successfully renovated, including the replacement of reactor control and protection system, the partial core and full core conversions of the reactor from HEU to LEU fuel, the upgrading of the physical protection

Reactor re-start with LEU fuel in control room

system, the installation of area radiation monitoring system, the removal and transportation of fresh and spent HEU fuel assemblies back to Russian Federation, etc. The studies on reactor physics, thermal hydraulics, and safety analysis of the DRR, both for theoretical calculations and experimental measurements, were carried out. The calculation for partial and full core conversions of the DRR has been performed in the collaboration with the Argonne National Laboratory of DOE/USA. Besides, researches on conceptual design of a new multi- purpose research reactor have also been realized in the co-operation with KAERI of Korea.

2. Research and production of many kinds of radioisotopes and radiopharmaceuticals used in medicine and other areas have been successfully performed. On an annual basis, it is possible to provide about 400 Ci of radioisotopes for medical use, of which the main products are 131I solution and capsule, 99mTc generator, 32P applicator, 32P, 51Cr, 153Sm, etc., solution, labeled kits in-vivo for 99mTc, kit in-vitro T3, T4, etc. Each year, about  500,000  patients  have  been  diagnosed  and  treated  by  radioisotopes  supplied  by  DNRI.  Other radioisotopes and radioactive tracers for sedimentology study, oil field, and industrial applications, such as 46Sc, 192Ir, 198Au, etc., have also been produced and distributed to end-users.

Hot cell and I-131 production line	Products of Radioisotopes and Radiopharmaceuticals

3. Neutron filters have been made and assembled at horizontal channels of the reactor to form thermal and quasi-monoenergetic neutron beams, such as 2keV, 24keV , 54 keV, 59 keV, 133 keV,148 keV, etc. The nuclear spectroscopy systems have been installed at 3 horizontal channels No. 2, No. 3 and No. 4 of the reactor, and specialized softwares have been developed for data processing. These beams have been used for measurements of nuclear reaction data and nuclear structure data based on (n,g), (n,2g) and (n,3g) reactions. They also have been utilized for prompt gamma  neutron  activation  analysis,  measurement  of  neutronporosity  in  base-rock  for  oil  fields,  irradiation  of  electronic components for radiation hardness study, study of Boron neutron capture therapy (BNCT) technique, etc. In addition, the neutron irradiation of gemstones in the reactor core, in the rotary rack outside the core, as well as in the horizontal channels for coloration experiments has also been carried out.

Assembling neutron filters

4. Analytical science has been studied and developed in a variety of techniques including nuclear and physico- chemical methods. A combination of different techniques comprising instrumental neutron activation analysis (INAA), radiochemical neutron activation analysis (RNAA), prompt gamma neutron activation analysis (PGNAA), X-ray fluorescence analysis (XRFA), and physico-chemical methods with HPLC, LSC, AAS, ICP- MS, GC, IC, UV-vis, etc., systems has made DNRI become a complete center providing analytical services for the South-eastern region and the Central Highlands in particular and the whole country in general. So far, these techniques may be used to accurately analyze up to 70 elements and constituents in various samples of geology, crude oil, agriculture, biology, environment, archaeology, etc. Each year, DNRI analyzes more than 6,000 samples using the above mentioned techniques. Additionally, K0 - method for INAA has been successfully established to analyze airborne particulate samples in investigations of air pollution, samples of crude oil, samples of base rock in oil field study, and archaeological samples as well.

5. Environmental radioactivity research and monitoring have been carried out since DRR was put into operation. Radioactive concentration in  the  air,  fallout,  surface  water,  underground water, waste water, surface soil, sediment, vegetation and food has been monitored periodically. Up to now, about 17,000 environmental  samples  have  been  collected,  analyzed  and stored. DNRI is managing three monitoring stations located in DRR area, in Ho Chi Minh City and in Ninh Thuan province. Since 1997, the station at DNRI has become a national environmental monitoring station. Researches on marine environmental radioactivity have also been carried out during the last ten years. These researches will play an important role in the evaluation of impacts on environment of activities related to nuclear power plans.

   Environmental monitoring station at DNRI

6. The radioactive tracer techniques have been developed and applied successfully by DNRI. The artificial            radiotracers, such as 46Sc, 192Ir, ¹⁹⁸Au producted in DRR have been utilized  for  studying  sediment  dynamics  in  coastal  and  estuarine zones. The environmental radioisotopes (7Be, 137Cs, 210Pb, nuclides in Uranium and Thorium chains) have been applied in studies of environmental processes such  as  soil  erosion, sedimentation rates, sediment sources, residence time and diffusion coefficient of coastal water, etc.

Surface sediment sampling at a coastal zone

7. DNRI has succeeded in the research and development of radiation technology  for  the  preservation  of  food,  sterilization  of  medical devices,  and  modification  of  materials.  The  research  results  on radiation   technologies   at   DNRI   have   laid   scientific-technical foundation of the establishment of irradiation centers on an industrial scale in Vietnam.Radiation  technology has also been utilized for production of various  plant  growth promoters,plant protectors, etc. In recent years, biological environmental products have also been studied using radiation technology.

Cobalt-60 “Issledavachel” and “GAMMA CHAMBER -5000” irradiators	Products serving agricultural

11. DNRI has  played a  very  important role in  the reinforcement of material and technique potential, manpower development, enlarging the market for applications of nuclear technology and science, taking part in the program of introducing nuclear power for electricity production into Vietnam. Manpower training for the DNRI and for nuclear energy programme of Vietnam in the near future is one of the main tasks of DNRI.

12. Apart from scientific activities as described above, DNRI also takes responsibility for:

• Providing the     public           with     nuclear   science information   and introducing them  to            different activities of DNRI and VINATOM.
• Organizing national and international workshops.
• Compiling nuclear science syllabi.
• Tutoring  students  of  different  levels,  e.g.  high school, and post graduate students
• Performing domestic/international cooperation on nuclear science and technology.

Along this line, DNRI has enthusiastically taken part in various national science and technology fairs and exhibitions, and has successfully co-organized different training courses (on  the  use  of  nuclear techniques in industry and environment, nuclear reactor engineering, radiography test, ultrasonic test, etc.) with other foreign institutions and organizations, (e.g. JAEA of Japan, BARC of India, DOE of USA, etc.).

Meeting of the Regional Advisory Safety Committee for Research Reactors

in Asia and the Pacific

Signing ceremony of the cooperation agreement between Most and Rosatom

in training Vietnamese staff for CNEST