Final Flashcards
(21 cards)
What is the formula for extraction factor and what does each term mean?
Beta = E*D/F where D is the distribution coefficient, E is the organic phase and F is the aqueous phase
What is the formula for the decontamination factor?
f = overall recovery for Uranium / overall recovery of FP or other isotope
What is the formula for the toxicity?
Toxicity = SUMMATION{ Lambda_i * N_i / C_i} where lambda is the decay constant of i isotope, c_i is the concentration in uCi/mL, and N is the number of atoms of that isotope
Describe the 5 major steps in the PUREX reprocessing?
- Decladding
- Dissolution: dissolves UO2 SNF in NO3
- Conditioning: change the solution condition (pH, redox)
- Decontamination: separate Pu/U from other FP
- Pu/U separation
What is the waste matrix of high-level waste from reprocessing?
Borosilicate glass
What are the 7 main radionuclides that have high contribution to the mean annual dose of the YMR?
- Tc-99
- I-129
- Np-237
- C-14
- Pu-239
- Se-79
Describe the three engineered barriers in YMR?
Waste form and Waste package/canister (limits radionuclide release), and Drip shield (limits water dripping on packages and prevents corrosion.
Describe one difference between YMR and Finish repository relevant to the mobility of radionuclides?
YMR is within the unsaturated condition (above the water table), which makes the radionuclides relatively mobile
If the mass loading of Np-237 in each canister is doubled, does the mean annual dose from Np-237 becomes twice? Assume that the release is solubility limited.
No. The mean annual dose is a function of concentration, which is the function of the source concentration. Since the source concentration does not change (solubility), the mean annual dose does not increase
What are the 6 main processes within front end cycle?
minining, milling, refining, conversion, enrichment and fuel fabrication
What is th eproduct of mining?
U ore
product of milling?
yellow cake
product of refining
uraniium oxide
product of conversion
UF6
Product of enrichment
UF6
product of fuel fabrication
UO2
What is the %U in U ore?
0.2-20%
What is the %U in yellow cake?
70-90%
What is the U 235 ENRICHMENT IN NATURAL URANIUM?
0.72%
What is the implicaiton of oxygen for unraium mobility?
In oxidation condition, uranium is mobile, uranyl ions migrate in the oxidizing conditions in subsurface, and precipitate when they hit the reducing enviroment. It then causes an accumulation of uranium in a region where the redox condition changes
What is congruent release?
The fractional release rate of the radionuclide is equal to its mass fraction in the waste form.
