def theU235_lamda
      array = Array.new(23)

      array[0] = 2.2138E+01
      array[1] = 5.1587E-01
      array[2] = 1.9594E-01
      array[3] = 1.0314E-01
      array[4] = 3.3656E-02
      array[5] = 1.1681E-02
      array[6] = 3.5870E-03
      array[7] = 1.3930E-03
      array[8] = 6.2630E-04
      array[9] = 1.8906E-04
      array[10] = 5.4988E-05
      array[11] = 2.0958E-05
      array[12] = 1.0010E-05
      array[13] = 2.5438E-06
      array[14] = 6.6361E-07
      array[15] = 1.2290E-07
      array[16] = 2.7213E-08
      array[17] = 4.3714E-09
      array[18] = 7.5780E-10
      array[19] = 2.4786E-10
      array[20] = 2.2384E-13
      array[21] = 2.4600E-14
      array[22] = 1.5699E-14

      array
    end
def theU235_lamda
      array = Array.new(23)

      array[0] = 2.2138E+01
      array[1] = 5.1587E-01
      array[2] = 1.9594E-01
      array[3] = 1.0314E-01
      array[4] = 3.3656E-02
      array[5] = 1.1681E-02
      array[6] = 3.5870E-03
      array[7] = 1.3930E-03
      array[8] = 6.2630E-04
      array[9] = 1.8906E-04
      array[10] = 5.4988E-05
      array[11] = 2.0958E-05
      array[12] = 1.0010E-05
      array[13] = 2.5438E-06
      array[14] = 6.6361E-07
      array[15] = 1.2290E-07
      array[16] = 2.7213E-08
      array[17] = 4.3714E-09
      array[18] = 7.5780E-10
      array[19] = 2.4786E-10
      array[20] = 2.2384E-13
      array[21] = 2.4600E-14
      array[22] = 1.5699E-14

      array
    end
theU235_lamda is lamda in ANS-5.1-1979 Table 7.