f-- V,, nnna UNIT TENAGA NUKLEAR, JABATAN PEROANA MENTERI. NUCLEAR ENERGY UNIT, PRIME MINISTER'S DEPARTMENT. MALAYSIA PAKISTAN RESEARCH REACTOR AND ITS UTILIZATION by • Iqbal Hussain Qureshi and Natem Ahnad Khan Paper Presented at the IAEA Seminar Ch Effective Utilization and Management of Research Reactor 7-11 Novenfoer, 1983 Kuala Lunpur MAIAYSIA PAKISTAN RESEARCH REACTOR AND ITS UTILIZATION IOJ3AL HUSSAIN QURESHI and NAEEM AHJIAO KHAN To be presented at the Seminar on Effective Utilization and Management of Research Reactors, Kuala Lumpur, Ma^sia, 7 to 11 November, 198 3 Pakistan Institute of Nuclear Science and Technology Nilore, Rawalpindi October, 1983 CONTENTS Abstract 1 1. Introduction 2. Pakistan Research Reactor 3 2.1 The Reactor 3 2.2 Neutron Flux . 3 3. Reactor Utilization for Research 3.1 Physics Research o 3.1.1 Neutron Diffraction Studies 5 3.1.1.1 Elastic diffraction studies of KCl.KBr, RbCl and T1C1 6 3.1.1.2 Lattice dynamics of KQ 5RbQ =1, KC1Q 5, Rbn -Cl and Copper-Nicle alloys 6 3.1.1.3 Structue Studies of Cellulose-I, Cellulose-II and deutrated Cellulose 7 3.1.1.4 Determination of oxygen ratio in uranium xides 8 3.1.1.5 Concentration Dependence of Debye Temperature in Mixed Alkali Hal ides, K Rb. I,K Rb. F, 3.1.1.6 Order-disorder Phase Transition Studies Iron-based alloys ^ 3.1.1.7 Texture studies in sheets of copper and alumium 9 3.1.1.8 Study of superionic conductors 10 - 3.1.2 Radiation Damage Studies 10 . 3.1.3 Thermal Neutron Capture -Ray Spectroscopy 11 3.1.3.1 Nuclear Structure 11 3.1.3.2 Protein content of Cereal 12 3.1.3.2.B. Burn-up Measurements 12 3.1.4 Fission Physics Studies 12 3.2 Chemistry Research 13 3.2.1 Radioisotope Production 13 3.2.1.1 Chemical Processing of Irradiated Tellurium for Iodine-131 14 3.2.1. Neutron Activation Analysis 16 3.2.2.1 Geological and High Purity Materials 17 -*^ 3.2.2.2 Biological and Environmental Materials 18 3.2.2.3 Fuel Element as a Source of Gamma Radiation 20 4. Neutron Radiography Facility 23 5. Training 23 5.1 M.Sc. Nuclear Engineering Degree Course 23 5.2 Reactor Operator and Supervisor's Licence 24 Acknowledgement 25 References 26-28 Contents of Tables 29 Contents of Figures 35 PAKISTAN KESEARCH HEACTOR AXD ITS UTILIZATION by IQBAL HUSSAIX QURESHI AND NAEEM AHMAD KHAN Pakistan Institute of Nuclear Science and Technology (PIXSTEC'I) P.O. Nil ore, Rawalpindi, PAKISTAN ABSTRACT The 5 MW enriched uranium fuelled, light \vater moderaifd and cooled Pakistan Research reactor became critical on 21st December, 1965 and was taken to full power on 22nd June, 1966. Since then it has been operated for about 23000 hours till 30th June, 1983 without any major break down. It has been used for the studies of neutron cross-sections, nuclear structure, fis.sio physics, structure of material, radiation dairage in crystals and semi-conductors, studies of geological, biololog ' "~ environmental samples by neutron activation techniques, r_«. isotope production, neutron radiography i for training of scientists, engineers and technicians. In he paper we have described briefly the facility of Pakistan Research Reactor and the major work carried around it during the last decade. PAKISTAN' RESEARCH REACTOR AND ITS UTILIZATION 1. INTRODUCTION Pakistan Institute of Nuclear Science i Technology is the premier research and development establishment of Pakistan Atomic Energy Commission. Keeping in view the objective of the Commission, this Institute has been assigned the task-s of: a? supporting the development of nuclear power programme b) production of radioisotopes, and c) popularizing the use of radioisotopes and radiation sources in industry, hydrology etc. for peaceful purposes. As a consequence this Institute is multidiscinline in character .and has well established laboratories in nuclear physics, nuclear chemistry, nuclear materials, nuclear engineering etc. The layout of the Institute is shown in Fig.l. Since any institute of this type requires a large capital investment, it is expedient particularly in a developing country to establish it in a phased programme. This has been also the case in PINSTECH. Though the 5 MW Swimming Pool reactor, which is central facility of the Institute became critical in December, 1965 and was taken to full power in June, 1966, yet the last of the associated laboratory became operational around 1972. Since then the reactor and its associated laboratories have been used for research in the following disciplines: (i) Nuclear and Solid State Physics and Material Science (ii) Radioisotopes production, (iii) Geological, Environmental and Biological Studies by Activation Techniques, (iv) Neutron Radiography, and (v). Training of scientists and engineers in nuclear science and engineering fields. In this paper we describe briefly the features of Pakistan Research Reactor and its utilization during the last 12 years or so under the above mentioned heads. 2. PAKISTAN RESEARCH REACTOR The reactor at Pakistan Institute of Nuclear Science and Technology is a 5 MV.' enriched uranium fuelled, light water j moderated and cooled research reactor. It has been operat' for about 23000hrs. producing an energy of 80,000 MWH. till 30th June, 1983 without any major break-down. It was, however, shut down for about four months from November 1979 to February 1980 for repairing of the seepages of water at some parts of the pool walls. 2.1 The Reactor The layout of the reactor and its associated experimental facilities is shown in Fig.2. The reactor core consists of the MTR type fuel elements and is located about 25 feet under water in a 32 feet deep open pool. The reactor is normally operated in the stall end of the pool which contains the research facil. ) ties whereas the open end of the pool is meant for storage and bulk irradiation studies. The research facilities include the following:- i) Six radial beam tubes, three of whicV are of 8" diameter and the remaining three art * 6" diameter. i ii) A 6" diameter tangential through tube. iii) A 5" diameter vertical tube for in-core irradiation of small samples. iv) Three 2" diameter pneumatic rabbit tubes which allow transfer of samples from and to the control stations at about 40 ft. per sec. One rabbit terminates in the hot cell while the other two serve the chemistry and radioisotope laboratories. v) A 41 x 41 wide and 5* deep graphite filled thermal column provided with a movable gate so as to allow access to the irradiation area inside the thermal column for any alteration and modifications in the set up. Four 6" diameter ports are also fitted to the gate for easy access to the graphite block for sample irradiations. vi) A dry irradiation room connected to the open end of the pool by a 21 x 2' aluminium win&pw. This room is intended for bulk irradiation with' gamma rays using the spent fuel elements, vii) A hot cell (not shown in Fig.2) with master- slave manipulators and a 21 x 2' pase-through port for the transfer of highly active samples from the reactor pool 2.2. Neutron Flux* The neutron flux measurements inside the reactor core and in various experimental facilities have been made by Qazi 2 3) et al ' , The flux distribution inside the core at full reactor power is 3.7x 10 13n/c m 2sec, with a cadmium ratio of 2.3. The thermal neutron flux at the thermal column face 7 2 ranges from about 8 x 10 n/cm .sec., in the centre to about 7 2 2 x 10 n/cm .sec , with a cadmium ratio of 1000, may be obtained at the end of hole produced by removing a 24" long, 4" x 4" graphite stringer from the thermal column. The thermal nuetron flux at the irradiation positions 12 12 of the three rabbit tubes lies between 5 x 10 and 9 x 10 2 n/cm .sec, the cadmium ratio is about 8. In the vertical tube the neutron flux depends critically on the position of the tube relative to the reactor core. The maximum thermal neutron flux that may be obtained in the verti- 13 2 cal tube is about 3 x 10 n/cm .sec with a cadmium ratio of about 2.5. •All value ^iven here have been extrapolated to full power of the reactor. Measurements were made using 25 micron thick gold foils and 1 mm thick cadmium covers. The thermal neutron flux inside an 8" diameter beam tube about 30 cm from the beam port face is 2 x 10 n/cm . se~ ' with a cadmium ratio of about 4. The flux at a corresponding q position inside a 6" diameter beam tube is only 2.4 x 10 n/c.-:; sec , with cadmium ratio of 6. The thermal neutron flux at the centre of the through tube is 1 x 10 1° n/cm 2 .sec. With a lead and paraffin collimator fitted in the tube to extract a. be:" of 1" diameter, the thermal neutron flux ar the beam port face was found to be 2.6 x 106 n/cm".sec*? . wirh a cadmium ratio of 3. By placing a D^O scatterer inside the tube near the reactor core the flux at the exit has been enhanced by a factor of 27. As highly enriched fuel is difficult to obtain graphite reflectors have recently been installed, on one side of the core, to conserve the in-hand fuel inventory. This measure has also resulted in .} neutron economy as the neutron flux in the vicinity of the graphic- reflectors is now enhanced by about 20%.