def calc_sum_thermal_fission(f_ts2t0, read_data)
      prd = ThermalData::HashWithThermalFission.new
      pd = 0
      prd.thermal_fission.each do |key, value|
        value = value + read_data.thePi[key] * f_ts2t0[key] / read_data.theQ[key]
        pd += value
      end
      pd
    end
def calc_sum_thermal_fission(f_ts2t0, read_data)
      prd = ThermalData::HashWithThermalFission.new
      pd = 0
      prd.thermal_fission.each do |key, value|
        value = value + read_data.thePi[key] * f_ts2t0[key] / read_data.theQ[key]
        pd += value
      end
      pd
    end
Calculate P'di (the uncorrected decay heat power) from ANS-5.1-1979 Eq.6
 need f_ts2t0, Pi(thePi), Qi(theQ) from class DataForANS_5_1_1979.

 calc_sum_thermal_fission(f_ts2t0, read_data)

 return P'd