Nuclear Fuel Cycle KD2430
2014-01-16, 800-1300
Please write readable. Write your name on every paper. Only one task per paper!
You can answer either in Swedish or English
You are allowed to use a calculator
Good Luck!
1.
Complete the nuclear reactions below
a. ____ → 251Fm + α
b. 90Sr → ____ + β
-
+
c. ____ → 101Rh + β
d. 64Zn → ____+ 1n + 1p
(4p)
2.
Why does a β-spectrum display a continuous peak and not one sharp peak at the very energy of
the decay? (2p)
3.
Does a stable isotope have odd or even numbers of protons?
Does a stable isotope have odd or even numbers of neutrons? (2p)
4.
Name three things that are conserved in a nuclear reaction. (3p)
5.
Give two radioactive isotopes that you naturally have in your body (2p)
6.
What does the LET-value describe? (2p)
7.
Give two of the three biggest contributors to give the annual dose in Sweden.
(Max 2p, 1p per correct contributor, -1 per incorrect contributor)
8.
What does the abbreviation ALARA stand for? (1p)
9.
Why is LiOH added to the reactor water in a PWR? (3p)
10.
How are impurities mainly removed from a nuclear reactor (2p)
11.
Why is the usage of cobalt minimized in the construction material of a nuclear reactor? (2p)
12.
What is actinide contraction? Relate complexation strength in the actinide series to actinide
contraction (4p)
13.
Relate the electronic configurations of the actinides to their unique properties (4p)
14.
What would be the safety and environmental concerns to consider if Sweden would start to
mine Uranium in for example Västergötland? (5p)
15.
Sketch the principles for the Swedish concept for a deep geological repository of spent nuclear
and give the chemical and geological properties that give the barrier functions of the repository
(6p)
16.
A γ-detector with an efficiency of 2% is held 2 m. from a vial containing radionuclides. The
detector has a diameter of 5 cm. The detector gives a response of 23 cps. What is the activity of
the radionuclides in the vial? (2p)
17.
61
18.
Gallium occurs in trace amounts in bauxite. The content of Ga in a bauxite sample is to be
determined using neutron activation analysis. 5.12 gram bauxite is irradiated in a neutron flux
of 2×1012 n·cm-2·s-1 for 5 hours. The β-activity of the sample was measured one hour after the
irradiation and was found to be 4.505 MBq.
What is the Ga-content in the sample? Answer in ppm (parts per million based on weight) (6p)
Below is the part of the nuclide chart that you need to solve the problem.
Co has a half-life of 1.65 h and decays to 61Ni, which is a stable isotope. If the ratio 61Co/61Ni
is 1.6327, what will the ratio be two hours later? (4p)
Ge 70
20.38
σ 3.0
Ga 69
60.108
σ 3.0
Zn 68
19.024
σ 0.87
Ge 71
11.43 d
ec
no γ
Ga 70
21.15 m
β- 1.7…
γ (1040; 176)
Zn 69
56 m
β- 0.9
γ (319…)
Ge 72
27.31
σ 0.9
Ga 71
39.892
σ 4.7
Zn 70
0.631
σ 0.08
Ge 73
7.76
σ 15
Ga 72
14.1 h
β- 1.0; 3.2
γ 834; 2202…
Zn 71
2.4 m
β- 2.8
γ (512;910…)
19.
When studying adsorption of ions to minerals Kd-values are often used. The Kd-value is defined
for a system in equilibrium as
Kd =
amount adsorbed species per mass mineral
amount species still in solution per volume unit
Hence the unit for the Kd-value is cm3/g.
In an experiment the adsorption of potassium was to be studied. 4.05 grams of rock was placed
in a well stirred beaker filled with 30 ml water and 447 mg dissolved KCl. The system was left
for equilibration for four weeks. After that a stock solution was prepared by dissolving 74.5 mg
KCl in 5 ml water. A very small
volume containing 30.0 kBq 43K (see
Time
Measured
Ca 43
Ca 44
[h]
activity [cps]
figure to the most-right for properties)
0.135
2.086
12
58.44
was added to the stock solution.
σ 0.6
σ6
24
29.78
The stock solution was then added to
K 42
K 43
36
19.82
the solution containing the rock.
12.36h
22.2h
48
13.52
β- 0.8…
0.2 ml samples were taken at 12 h
60
9.22
σ 3.0
γ 373…
72
6.34
interval and analyzed for β-activity on a
liquid scintillator that had an efficiency of 81.7%. The results can be seen in the table.
What is the Kd-value for adsorption of potassium to the rock used in the experiment? (8p)
Periodic Table of the Elements
H 1
He 2
1.0079
4.0026
Li 3
Be 4
B 5
C 6
N 7
O 8
F 9
Ne 10
6.941
9.01218
10.81
12.011
14.0067
15.9994
18.9984
20.179
Na 11
Mg 12
Al 13
Si 14
P 15
S 16
Cl 17
Ar 18
22.9898
24.305
26.9815
28.0855
30.9736
32.06
35.453
39.948
K 19
Ca 20
Sc 21
Ti 22
V 23
Cr 24
Mn 25
Fe 26
Co 27
Ni 28
Cu 29
Zn 30
Ga 31
Ge 32
As 33
Se 34
Br 35
Kr 36
39.0983
40.08
44.9559
47.88
50.9415
51.996
54.9380
55.847
58.9332
58.70
63.546
65.38
69.72
72.59
74.9216
78.96
79.904
83.80
Rb 37
Sr 38
Y 39
Zr 40
Nb 41
Mo 42
Tc 43
Ru44
Rh 45
Pd 46
Ag 47
Cd 48
In 49
Sn 50
Sb 51
Te 52
I 53
Xe 54
85.4678
87.62
88.9059
91.22
92.9064
95.94
98.906
101.07
102.96
106.4
107.868
112.41
114.82
118.69
121.75
127.60
126.9
131.30
Cs 55
Ba 56
La 57
Hf 72
Ta 73
W 74
Re 75
Os 76
Ir 77
Pt 78
Au 79
Hg 80
Tl 81
Pb 82
Bi 83
Po 84
At 85
Rn 86
132.9
137.33
138.91
178.49
180.948
183.85
186.207
190.2
192.22
195.09
196.966
200.59
204.37
207.2
208.980
(209)
(210)
(222)
Fr 87
Ra 88
Ac 89
Rf 104
(223)
226.025
227.028
(261)
Db 105 Sg 106
(262)
(266)
Bh 107 Hs 108 Mt 109 Ds 110 Rg 111 Cn 112 Uut 113 Fl 114 Uup115 Lv 116 Uus 117 Uuo 118
(264)
(269)
(270)
(269)
(272)
(277)
(-)
(287)
(-)
(291)
Ce 58
Pr 59
Nd 60
Pm 61
Sm 62
Eu 63
Gd 64
Tb 65
Dy 66
Ho 67
Er 68
Tm 69
Yb 70
Lu 71
140.12
140.9077
144.24
145
150.4
151.96
157.25
158.9254
162.50
164.9304
167.26
168.9342
173.04
174.967
Th 90
Pa 91
U 92
Np 93
Pu 94
Bk 97
Cf 98
232.0381
231.0359
238.029
237.0482
(244)
(247)
(251)
Am 95 Cm 96
(243)
(247)
Es 99 Fm 100 Md 101 No 102 Lr 103
(254)
(257)
(258)
259
260
(-)
(-)