Nuclear Power

Question 1

Chain reaction:
4% of U-235 goes into a chain reaction. How is the reaction further? (See calculation slides for visualization)

Answer 1

75% U-235 reacted —> (1U-235 atom fissioned -> 0.6 PU-239 atoms)
0.6 PU-239 —> 50% reacted PU-239

Question 2

Estimate amount of energy uranium consumed every year in a reactor

Answer 2

Capacity * Time * Load factor * 1/Efficiency = energy [TJ/year]

Anpassa tid efter angiven!! Här år: 365 days/year * 24 hours/day * 60 min/hour * 60 s/min

Question 3

Avogrado’s constant

Answer 3

6*10^23 atoms / mol

Question 4

1 eV in Joules

Answer 4

1 eV = 1.6 * 10^-19 J

Question 5

What is the convertion of molar mass to kg in U-235?

Answer 5

1 mol U235 = 0.235 kg U235

Question 6

The energy of 1 kg U-235

Answer 6

Avogrado’s constant [atom/mol] * energy released in fission [Mev/atom] * conversion of 1eV to joles [J] / (1 mol of U-235 in kg [kg/molU235])

In numbers:

610^23[atom/mol] * 200 [MeV/atom] 1.6*10^-13 [J/MeV] / 0.235[kg/molU235]

Question 7

Amount of U-235 needed in one year

Answer 7

For this you need: 1. Energy needed for 1 reactor and 2. Energy in 1 kg of U235

Energy in reactor [TJ/year]/ (energy in 1kg of U235[TJ/kg] * chain reaction = [kg U235 / year]

Chain reaction: (1+(0.6/2) fissions * 0.75)

Question 8

Chain reaction

Answer 8

(1+ 0.6/2) fissions * 0.75

0.75 = 75% of U235 has undergone fission
0.6 = atoms of plutonium generated for every uranium atom that is fissioned
0.6/2 = half of the plutonium undergoes fission

1 = uranium that undergone fission

Question 9

Estimate amount of fuel needed of uranium metal to operate the reactor

Answer 9

Amount of U-235 needed [kgU235/year]/ enrichment of U-235

Question 10

Levelised cost of investment Lc

Answer 10

Lc = (investment/ Es ) * CRF

Es = 1kW * 365 * 24* load factor

CRF = r/ (1-(1+r)^-T)

r: discount rate
T: life time of plant