[en] The information on daily dietary intake along with the organ burdens of trace elements of radiological importance, could provide population specific data on biokinetic parameters that are important for accurate internal dose assessment, when humans are exposed to these trace elements or their radioactive counterparts. Sensitive and reliable analytical methods were developed and applied to obtain the daily dietary intake data on Cs, Sr and I for application in the development of the biokinetic parameters of their radioactive counterparts: ¹³⁷Cs, ⁹⁰Sr and ¹³¹I. The data obtained so far on the daily dietary intake of Cs, Sr and I for an adult reference Indian was observed to be 4.1 μg, 1040 μg, 227 μg respectively. The analysis of individual food items showed that significant amount of Cs in daily diet was contributed by cereals and pulses. In the case of higher income group consuming five times more milk than the national average, milk could become main contributing factor for dietary Cs. The major contribution of Sr intake comes from cereals and that of I comes mainly from iodised salt

[en] The concentrations of Cs, Sr, K and Ca in total diet and in major food components were determined using the sensitive and reliable analytical method involving the neutron activation analysis technique. The mean concentration of the Cs, Sr, K and Ca in diet were found to be 8.5 ng/g, 2.72 μg/g, 3.45mg/g and 0.60 mg/g respectively. In food materials the elemental concentrations varies from 0.39 -30.40 ng/g for Cs, 0.14-3.75 μg/g for Sr, 0.90-6.8 mg/g for K and 0.036-2.40 mg/g for Ca respectively. The mean concentrations of Cs, Sr, K and Ca in diet and in other food samples were employed to obtain their Cs/K and Sr/Ca ratios. These ratios can be of use in predicting the Sr and Cs contents in body organs of interest based on the knowledge Ca and K content in the organs. The mean Cs/K ratio of 1.82 E-06 in the food materials was found to be comparable with that of 2.46E-06 in diet. Whereas the mean Sr/Ca ratio of 6.89E-03 obtained from the food materials was found to be twice that of total diet (3.33E-03).(author)

[en] The daily dietary intake and urinary excretion of thorium in normal subjects were estimated by analyzing their duplicate diet samples and 24 hour urine samples using neutron activation analysis method. The samples are processed and neutron irradiated along with the standard, chemically separated ²³³Pa and counted using gamma spectrometry. The estimated values of daily intake and urinary excretion of thorium were used for the estimation of gut absorption factor (f1), an important bio-kinetic parameter used in the accurate assessment of internal dose to the exposed persons. The comparison of the f1 values of thorium obtained in the present work with the ICRP reported value reveals that the gut absorption factor values for normal Indian subjects were significantly greater than that of ICRP reported value. (author)

[en] In this study, the data on daily dietary intake of stable strontium and its content in blood serum for adult Indian population were estimated and employed to obtain the gut absorption factor f₁, which then can be used for the biokinetic studies of its radioactive counterparts

[en] The daily dietary intake and the quantity of cesium (Cs) present in skeletal muscle for Indian adult male population were estimated by determining its concentration in diet and muscle tissue samples, using neutron activation analysis. The concentrations of Cs in individual food ingredients that form important component of daily diet were also determined and utilised to estimate their contribution to its average intake by an urban adult male. These data were then employed to predict the biological half-life of its radioactive counterpart ¹³⁷Cs for an adult Indian Reference Man as well as for the urban adult population. The predicted biological half-life for Reference Adult Male was found to be comparable and that for adult urban male was shorter in comparison to that proposed by ICRP. The predicted half-life of ¹³⁷Cs for urban adult however, was found to be comparable to the reported value, obtained from the follow-up studies for occupational workers exposed to ¹³⁷Cs. (author)

[en] The daily dietary intake of strontium and its content in blood serum for Indian adult population were estimated experimentally by measuring the concentration of stable Sr in total cooked diet and blood serum samples using radiochemical neutron activation analysis technique (RNAA). This paper reports some preliminary results obtained in the estimation of gut absorption factor (f₁) values of Sr in Indian adult population using data on it's daily dietary intake and blood serum content. The estimated f₁ values of Sr in Indian adult population were compared with the reported ICRP values. (author)

[en] Thorium-232 (²³²Th) is a natural radioactive element and is also a potential source of nuclear fuel (²³³U). Although usually present in low concentrations in soil, it is found in large quantities in certain parts of India (coastal regions of Kerala, Tamilnadu and Orissa), Brazil and Egypt in the form of monazite. The population gets exposed to this radionuclide by living in high background areas and also during the mining and processing of the radioactive mineral monazite. The intake of this radionuclide by general public or occupational workers could lead to its deposition in the body organs and subsequently to internal doses. It is, therefore, important to study the bio-kinetics of Th to evaluate the extent of health hazard due to its intake by the exposed persons. This paper reports the data on concentration of thorium in different food materials consumed by Indian population, its daily dietary intake which can be used for the estimation of important bio-kinetic parameters such as biological half-life, gut absorption factor (f₁), etc. which are used in the accurate assessment of internal dose to the exposed persons

[en] The pressurized Heavy Water Reactor (PHWR) consists of horizontal calandria vessel containing a large number of pressure tubes (fuel channels) connected to the reactor inlet and outlet headers by individual feeders. Coolant flow distribution among the pressure tubes play a vital role in extraction of thermal power. For these reactors one of the design objectives is to achieve uniform coolant outlet temperatures by providing coolant flows according to the channel power. This is achieved by the design process known as feeder sizing. This basically consists of accounting for the individual channel power and centre line geometry of individual feeder and iteratively adjusting the feeder hydraulic resistances within the design constraints such as limiting flow velocities, channel flows. Recently, the first unit of 540 MWe i.e Tarapur Atomic Power Project (unit 4) has been commissioned. This paper discusses the verification of the coolant flow distribution in the core with the design estimated flow during different commissioning phases. (author)

[en] In a 540 MWe PHWR reactor at TAPP-4 the pressuriser has been incorporated in the PHT pressure control system to provide the necessary vapour cushion for PHT main circuit to reduce pressure variations due to transients involving swell and shrinkage. Need for the Pressuriser is due to the large inventory in PHT main circuit and relatively large heat source. The incorporation of Pressuriser is one of the modifications while upgrading from prevalent operating 220 MWe reactors to the present 540 MWe at TAPP-4. The sizing, design and selection of the 540 MWe Pressuriser has been done w.r.t swell/shrinkage requirement during normal/transient operation of the reactor. In this paper the commissioning and operating experience of the Pressuriser in conjunction with the PHT pressure control system is presented. During light water commissioning of PHT circuit some major hurdles like failure of pressuriser heaters due to faulty instrumentation were faced. Subsequently the following corrective action was carried out. The cause of instrumentation/logic fault was reviewed and rectified, heaters were reinstalled, level instrumentation behaviour was repeatedly checked with light water, the pressuriser normal operating level and heater cut-off level was also raised, the performance of the Pressuriser with the revised levels was checked by analysis. After heavy water filling various tests carried out on the pressure control system which confirmed the effectiveness of the pressuriser. The ongoing smooth operation of TAPP-4 at 90 % FP also justifies the requirement of Pressuriser in 540 MWe PHWR. (author)

[en] Internal Dosimetry Division of Bhabha Atomic Research Centre has applied neutron activation analysis technique for estimation of Th and U in various matrices and the same technique is being used on regular basis for bioassay monitoring of occupational workers. Radiochemical separations were performed, wherever required