Analysis of activity concentrations due to natural radionuclides in the fish of Kainji Lake

A study was conducted for natural radioactivity of some fish samples from Kainji Lake, situated between latitudes 9~' 50' - 10~' 57' North and longitudes 4~'25'-4~'45' East, New Bussa, Niger state, Nigeria, using gamma spectroscopy method with Nal(TI) detector. Radioactivity a phenomenon that leads to production of radiations, and radiation is known to trigger or induce cancer. The fish are analyzed to estimate the radioactivity (activity) concentrations due to natural radionuclides (Radium 222(226Ra), Thorium 232(232Th) and Potassium 40 (40K). The obtained result shows that the activity concentration for (226Ra), in all the fish samples collected ranges from 16.06 ~c 0.44 Bqkg-1 to 67.39 ~c 12.34 Bqkg-1 with an average value of 37.22 ~c 4.31 Bqkg-1. That of 232Th, ranges from 42.66 ~c 0.81 Bqkg-1 to 200.6 ~c 10.66 Bqkg-1 and the average value stands at 94.82 ~c 3.82 Bqkg-1. The activity concentration for 40K, ranges between 243.3 ~c 1.56 Bqkg-1 to 384.98 ~c 11.97 Bqkg-1 and the average is 618.2 ~c 26.81 Bqkg-1. This indicated that average daily intake due to natural activity from the fish is valued at 0.999 Bq/day, 2.545Bq/day and 10.31 Bq/day for 226Ra, 232Th and 40K respectively. This shows a promising result, since the activity concentration values for most of the fish are within the acceptable limits. However location Upstream02 (9~'51'.285~AN, 4~'35'.533~AE) and Upstream07 (9~'51'.285~AN, 4~'35'.533~AE) fish, became outliers with significant values of 1 13.10~kSvy-1 and 121.68~kSvy-1 effective dose. This could be attributed to variation in geological formations in the lake as well as the feeding habits of these fish. The work shows that consumers of fish from Kainji Lake have no risk of radioactivity ingestion, even though no amount of radiation is assumed to be totally safe

Radioactivity level in water around a cement factory in north central Nigeria

In recent times, there has been consistent demand for drinkable water to meet the growing population of Obajana environs, where cement factory is situated. The mean gross alpha and beta activities in drinkable water around the communities of the cement factory, following a continuous exposure of workers and habitants was determined using a low background Gas-less counting system with solid state silicon detector for alpha and beta detection. The average activities for gross alpha and beta water ranged between 0.002871±0.00957 to 0.05335±0.0253 Bq/l and 0.2937±0.0588 to 39.96±11.3000 Bq/l, respectively. The alpha and beta geometric mean of the whole samples were found to be 0.0156±0.01487 Bq/l and 10.9±13.8373 Bq/l, respectively. The correlation coefficient (R), was found to be R = 0.8181, which shows there is a good relationship between the measured gross Alpha and Beta (activity). The average annual committed effective dose for water intake was between 0.149 mSv to 20.100 mSv, the recommended reference level for ingested dose for drinkable water was however exceeded in most locations, thus making the water in most locations not quite safe for consumption.Keywords: Water, Cement Factory, Effective dose, Gross Alpha and Gross Bet

Designing a 2D RZ Venture Model for Neutronic Analysis of the Nigeria Research Reactor-1 (NIRR-1)

A 2D RZ VENTURE model has been developed for the Nigeria Research Reactor-1 (NIRR-1) and this model was used to perform neutronic analysis for the system using the code “VENTURE-PC”. The major homogenized regions in the 2D VENTURE model include the active fuel region and the control region while the remaining components in the system geometry where modelled as closely as possible. The reactor physics parameters generated from the neutronic calculations include excess reactivity, control rod worth, shim worth, shutdown margin. The model predictions of these parameters for NIRR-1 system were in good agreement with experimental results as well as the results from similar calculations using different nuclear analysis tools. This 2D RZ VENTURE model gives an excellent simulation of the Nigeria Research Reactor-1 and the model will be very helpful in the future analysis of the system, as well for developing an LEU core model for future conversion of NIRR-1 from HEU to LEU fuelled research reactor. Keywords: Model, Neutronics, geometry, code, Design, Reactor, Simulation, Calculations, NIRR-1, Shim, Control, Shutdown, Physics. Peak, Density, Power, Flux, Neutro

Gross alpha and beta surveys of Lake Kainji water

A gross alpha and beta survey of the water of Kainji Lake was conducted using multi-channel analyzer, a proportional counter detector. This was done to estimate the gross radioactivity concentrations due to natural radionuclides in the lake water. Radioactivity, a phenomenon that leads to production of radiations, and radiation is known to trigger or induce cancer. The gross alpha and beta activity concentration analyzed in the water shows that the alpha activity ranges from 1.0 x 105 Bq/cm3 to 0.7Bq/cm3 with an average value indication of 0.0702Bq/cm3, whereas the beta activity concentration indicated BDL for all the sites with exception of upstream 01 location (9~' 51' 485' and 4~'35' 473'E) which has 0.0022Bq/cm3. This could be attributed to the continued flow of the lake water. Although radioactivity measured in lakes is usual higher than that of flowing waters, because a significant part of the radioactive substance brought in by other tributary rivers accumulates in it (Szaho et al.1998). That of Kainji Lake is entirely different