Isotope ingestion, calculation

In general formulas used to calculate the fraction of a stable isotope ingested which is recovered in feces using AAS to measure total mineral content are ... 

Calculation of Absorption Absorption of isotope doses by tiuman subjects was calculated by fecal monitoring (5), that is> by determining the amount of stable isotope ingesteT compared to the amount excreted in the feces in excess of the natural abundance The fractional absorption A (I-F E)/I where I is the amount of isotope ingested F is the total metal in the... 

As an illustration of the methods used in the assessment of the hazards from nuclear waste, we can take the calculation for the isotope Np, as computed by Cohen. This isotope decays with a half-life of 2.1 million yr by the emission of an alpha particle of energy 4.8 MeV the principal hazard arising from its ingestion is the induction of cancer of the liver. The first step... 

The cancer risk to the liver is known to be about 3 x 10 per Gy, so that the number of cancers induced by the absorbed dose from ingestion of 1 Ci is 2400. From the absorption cross sections of the isotopes involved, it can be calculated that Np is present in the high level waste at a level of 12 Ci per GWe yr (1 gigawatt, GW = 10 W). The number of liver cancers corresponding to the ingestion of the Np in the waste per GWe yr is therefore 27,000. Similar calculations can be done for the cancers induced in other organs, such as the bone and blood this yields a number of 38,000 for all types of fatal cancer combined. 

Within the task volume activity graphs were designed for each of the elements (in time). Another outputs of the task were maps showing substances concentration at the given sea level. Results obtained (for all the isotopes) were used in radioactive dose calculations. To determine the dose, the scenario of 1 m ground water drunk by a human being a year had been chosen. Based on that scenario ingestion factors were found (SKB 2002) and were stated for all the critical radionuclides shown in Table 3. 

Table 3. The ingestion factor for the critical isotopes, the maximal recorded volume activity on the surface element and the dose calculated basing on the given scenario.

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