NUCLEAR FUEL COMPLEX

• Sample Spectra

The samples were kept on the detector so that the activity could be counted. The samples were counted overnight to acquire it’s spectra. As the activity present in the samples is due to the presence of Potassium-40, the spectra is recorded and the activity is calculated accordingly.

The spectra were obtained for Bricks, Rock and Cement samples.

FIGURE - 6.2

Typical Spectra of Rock and Cement

FIGURE - 6.1

Typical Spectrum of Soil Sample

CALCULATIONS

Estimation of Activity

The peak counts under the peak of 1460KeV which is the signature peak of Potassium-40 was taken and the background contribution was subtracted from, for evaluating the Potassium-40 from the sample.

Now, the activity of the sample is calculated using the formula :

Activity (Bq/kg) = Nt*100*100*1/t*A*E%*W

Where Nt = Net counts = sample CPS - background CPS

A = Abundance of gamma line

E = Efficiency of the detector (%)

W = Sample weight (g)

The efficiency of the detector is calculated to be 0.54%

The gamma abundance is 10.7%

A typical spectra of the sample and rock sample are given in figure 6.1 and figure 6.2

Samples Counts Counting time Sample CPS

Brick 1 7082 87093 0.081

Brick 2 13125 85947 0.152

Brick 3 11150 86243 0.129

Rock 12311 86134 0.143

Cement 1 510 89664 0.005

Cement 2 2058 87298 0.023

Cement 3 7229 86997 0.083

Cement 4 7382 85877 0.066

RESULT & DISCUSSIONS

Result

There were three brick samples, a rock sample and four cement samples which were taken to analyze the activity of Potassium-40. The following table gives the result obtained of each sample.

FIGURE 7

The highest number of counts was observed in Brick 2 = 704±61.6 Bq/kg

Samples Weight/gm Net Counts (sample - background)

Activity (Bq/kg Counting Time

Brick 1 197 7082 135±54.2 87093

Brick 2 211 13125 704±61.6 85947

Brick 3 211 11150 515±58.2 86243

Rock 213 12311 619±59.7 86134

Cement 1 198 510 <35.4 89864

Cement 2 210 2058 <34.3 87298

Cement 3 218 7229 136±49.2 86997

Cement 4 181 7382 191±59.9 85877