In: Chemistry
a) Estimate the decay heat load from a 3000 MWt reactor at one day, one week, one month, and one year after shutdown from a 2-year run. b) Estimate the rate of heat up in a reactor core that has lost all of its coolant. Consider the decay heat loads found above. Assume the heat capacitance of the dry reactor core is 16,500 Btu/°F.
a. E(t) = 7.6*10-3* P[(t)0.8 - ( t+T)0.8 + (T)0.8 ] where
E(t) - Energy after period of t days in MWt.day
P - reactor power in MWt,
T - Period for which the reactor has run, in days
After 1 day:
E(1) = 7.6X10-3X3000 [ 10.8- (1+2X365 )0.8 + (2X365)0.8] = 22.8 [ 0.79] = 18.01 MWt.day = 18.01 X 106 X 24 X 60 X 60 Joules = 1556064 x106 Joules = 1474.86 X 106 Btu.
After 1 week ( 7 days ) :
E(7) = 22.8 [ 70.8 - ( 7+ 2x365 )0.8 + ( 2X365 ) 0.8 ] = 74.1 MWt.day = 74.1 X 106 X 24 X 60 X 60 Joules = 6402240 X 10 6 Joules = 6068.13 X 106 Btu.
After 1 month ( 30 days ) :
E(30) = 22.8 [ 300.8 - ( 30 + 2X 365 ) 0.8 + ( 2 X 365 )0.8] = 200.64 MWt day = 16430.62 X 106 Btu
After 1 year ( 365 days ):
E (365 ) = 22.8 [ 3650.8 - ( 365 + 2X365 )0.8 + ( 2X365 ) 0.8 ] = 851.35 MWt day = 69718.13 X 106 Btu
b. The rate of heat of up
After 1 day: decay heat / heat capacitance = 1474.86 X 106 / 16500 = 89.3 X 103 oF
After 1 week: 6068.13 X 106 / 16500 = 367.7 X103 oF
After 1 month: 16430.62 X 106/ 16500 = 995.8 X 103 oF
After 1 year: 69718.13 X 106/16500 = 4.22 X 106 oF