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answerhappygod
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Small Reactivities As shown in Fig. 7.2, the curve p (@)-that is, the plot of the reactivity equation- passes through the origin. This means that, for small reactivities, the first root of the equation is also small. In this case, the terms containing in the denominator of Eq. (7.27) or (7.32) can be ignored with the result P = M (4, + ₁) = 0 (1 + ΣAT.). +Σ) (+ΣΑ). (7.48) where 7,= 1/A, is the mean life of the ith precursor group. The reactor period can now be written as 1 T- = - = (1 + A²) Т (7.49) WI Values of the sum on the Right-Hand Side of Eq. (7.49) are given in Table 7.3 for the fissile nuclides. In all cases, this sum is much larger than the usual value of lp, and Eq. (7.49) reduces to ==ΣBITI. (7.50) TABLE 7.3 VALUES OF THE SUM ET, Nuclide Σβίι, sec 233 U 0.0479 215 U 0.0848 239 Pu 0.0324
Small Reactivities As shown in Fig. 7.2, the curve p (@)-that is, the plot of the reactivity equation- passes through the origin. This means that, for small reactivities, the first root of the equation is also small. In this case, the terms containing in the denominator of Eq. (7.27) or (7.32) can be ignored with the result P = M (4, + ₁) = 0 (1 + ΣAT.). +Σ) (+ΣΑ). (7.48) where 7,= 1/A, is the mean life of the ith precursor group. The reactor period can now be written as 1 T- = - = (1 + A²) Т (7.49) WI Values of the sum on the Right-Hand Side of Eq. (7.49) are given in Table 7.3 for the fissile nuclides. In all cases, this sum is much larger than the usual value of lp, and Eq. (7.49) reduces to ==ΣBITI. (7.50) TABLE 7.3 VALUES OF THE SUM ET, Nuclide Σβίι, sec 233 U 0.0479 215 U 0.0848 239 Pu 0.0324