Transmutation of radioactive waste on low-energy proton accelerators
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| Дата: | 1999 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
1999
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| Назва видання: | Вопросы атомной науки и техники |
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| Цитувати: | Transmutation of radioactive waste on low-energy proton accelerators / V.Ya. Migalenya, B.A. Voronko, V.G. Papkovich, N.A. Khizhnya // Вопросы атомной науки и техники. — 1999. — № 3. — С. 115-116. — Бібліогр.: 8 назв. — англ. |
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irk-123456789-813602015-05-15T03:02:39Z Transmutation of radioactive waste on low-energy proton accelerators Migalenya, V.Ya. Voronko, B.A. Papkovich, V.G. Khizhnyak, N.A. 1999 Article Transmutation of radioactive waste on low-energy proton accelerators / V.Ya. Migalenya, B.A. Voronko, V.G. Papkovich, N.A. Khizhnya // Вопросы атомной науки и техники. — 1999. — № 3. — С. 115-116. — Бібліогр.: 8 назв. — англ. 1562-6016 http://dspace.nbuv.gov.ua/handle/123456789/81360 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| format |
Article |
| author |
Migalenya, V.Ya. Voronko, B.A. Papkovich, V.G. Khizhnyak, N.A. |
| spellingShingle |
Migalenya, V.Ya. Voronko, B.A. Papkovich, V.G. Khizhnyak, N.A. Transmutation of radioactive waste on low-energy proton accelerators Вопросы атомной науки и техники |
| author_facet |
Migalenya, V.Ya. Voronko, B.A. Papkovich, V.G. Khizhnyak, N.A. |
| author_sort |
Migalenya, V.Ya. |
| title |
Transmutation of radioactive waste on low-energy proton accelerators |
| title_short |
Transmutation of radioactive waste on low-energy proton accelerators |
| title_full |
Transmutation of radioactive waste on low-energy proton accelerators |
| title_fullStr |
Transmutation of radioactive waste on low-energy proton accelerators |
| title_full_unstemmed |
Transmutation of radioactive waste on low-energy proton accelerators |
| title_sort |
transmutation of radioactive waste on low-energy proton accelerators |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
1999 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/81360 |
| citation_txt |
Transmutation of radioactive waste on low-energy proton accelerators / V.Ya. Migalenya, B.A. Voronko, V.G. Papkovich, N.A. Khizhnya // Вопросы атомной науки и техники. — 1999. — № 3. — С. 115-116. — Бібліогр.: 8 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-07-06T06:05:35Z |
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2025-07-06T06:05:35Z |
| _version_ |
1836876499096961024 |
| fulltext |
TRANSMUTATION OF RADIOACTIVE WASTE ON LOW-ENERGY
PROTON ACCELERATORS
V.Ya.Migalenya, B.A.Voronko, V.G.Papkovich, N.A.Khizhnyak
NSC KIPT, Kharkov, Ukraine
The problem of nuclear power-generating plant
radioactive waste transmutation is considered in the
literature approximately since 1958. On the one hand, it
is a major problem the solution of which determines the
development of ecologically pure nuclear energy on the
Earth. There are several solutions of this problem. On
the other hand, each of the proposed solutions is so
complicated in respect to engineering, and its successful
realization is arranged with so many` conventions, that
till now any of propositions is not seriously
implemented in the world. There is an only settled
concept of radioactive waste removal by their burial in
stable geological structures after solidification in the
form of glass or ceramics. The tectonic stability of these
structures during at least 1000 years will allow to reduce
the potential hazard to an acceptable level. And though
areas required for this storage, are rather small (about
3000 sq.m. for 1 GW electric power per year) the public
judgment believes such a solution unacceptable and it
the motivation in searching new, more effective
methods of transmutation of radioactive waste.
Analysis of the content of radioactive isotopes in
the irradiated fuel of a LWR reactor shows that
radioactive nuclides are characterized by a different
physical property, their quantity among the fission
products is various and they produce different danger
for the environment. The majority of nuclei even with a
very high activity (yttrium - 90, barium - 137, cerium -
144 etc.) have a small half-life period and their quantity
will decrease up to a safe level in time about 2-3 years.
Such radioactive fissile products form a group of short-
lived radioactive (SLRN) and they do not represent
serious danger for the environment. Other nuclei have a
half-life period about 10-30 years and a high activity
(strontium - 90, cesium - 137) and they decay up to a
safe level in time about 1000 years. They are to be
disposed or transmutated without fall by nuclear-
physical methods and are termed as long-lived
radioactive nuclides (LLRN). The intermediate group is
made with fissile nuclei with a half-life period of about
one year (ruthenium-106, cerium - 144, promethium -
147, europium - 154), transmutation of which, in our
opinion, is possible also at moderate energy accelerators
(hundreds of MeV).
In article [1] the problem of using fission
reactors with a high-energy neutron spectrum for
reducing the content of isotopes of krypton - 85,
strontium-90 and cesium - 137 in radioactive waste is
considered. In [2] the same problem was explored in the
assumption that neutron generators of are the protons of
the electronuclear installation. Application of a
thermonuclear reactor for transmutation was considered
in [3]. The numbered technologies are summarized and
investigated in the well- known paper [4] where the
following conclusions are made:
The destruction fission products, such as
strontium -90, cesium - 137, and krypton - 85 (LLRN)
by transmutation as a result of multiple irradiation
cycles at nuclear physical reactors of existing and
designed constructions is impossible because of lack of
high- neutron fluences sufficient for significant
lowering the effective half-life period of the majority of
these nuclides. The reaching of such a purpose requires
making in special reactors of the neutron density of
about 1017 neutron/cm2s. Possible variants can be only
electronuclear reactors, since in thermonuclear reactors
the density of neutron fluences is less by one order of
magnitude. However studies which have been carried
out in NSC KIPT, [5], evidence that in BNL papers we
refer the inexactness is supposed. In the process of
burning out cesium - 137 in an intensive neutron fluence
with a density of 1017 neutron/cm2s in a spectrum of
neutrons generated in the target - converter of a linac,
the section of radioactive capture will be strongly
suppressed by the parallel nuclear reactions and,
consequently, the time of a burning out of this isotope
increases from two till ten years, that is completely
unacceptable. Additional investigations we have carried
out have shown, that the isotope cesium - 137 can rather
effectively transmute in direct reactions with low-
energy protons. This conclusion obtained by theoretical
methods, puts on practical ground all the problem of
LLRN transmutation using the moderate- energy proton
beams.
To carry out analysis of the process of fission
product transmutation with the beam of protons of an
energy less than 50 MeV, the excitation functions for (p,
xn yp) reactions on nuclei 85Kr, 88Sr, 90Sr, 99Tc, 107Pd,
133Cs, 137Cs, 151Sm were calculated. The calculations
were carried out on a statistic model of a compound
nucleus with taking into account the preequilibrium
decay [7].
From our results it follows that 85Kr, 90Sr, 107Pd under
irradiation with the Ep < 50 MeV proton beams the
stable or short-lived nuclides are formed. In the case of
99Tc the irradiation with > 25 MeV protons leads to
formation of radioactive nuclei 97Tc, 96Tc and 93Mo with
half-life periods of 4.6·106 years and 3.5·103 years,
respectively.
Under irradiation of 137Cs at Ep > 30 MeV the
channels of (ð, 5n) and (p, p2n) reactions are opened,
that allows one to produce 133Ba (T1/2=10.54 years) and
135Cs (T1/2=2.3*106
years), and for 151Sm over total
energy range the production of long-lived nuclides takes
place.
The results of calculation of excitation functions
for reactions on stable isotopes 88Sr and 133Cs show that
the peak value T1/2 of nuclides generated during
interaction between protons and 88Sr is 106.6 days, and
in the case of 133Cs it is 10.54 of year, i.e. the additional
quantity of long-lived nuclides is yielded that reduces
the efficiency transmutation. The total reaction cross-
sections of 88Sr and 133Cs are close to cross-sections of
radioactive nuclides of strontium and cesium, that
results in additional consumption of the accelerated
beam for reprocessing. Generally, independently on the
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. №3.
Серия: Ядерно-физические исследования. (34), с. 115-116.
115
transmutation method, "burning out" of long-lived
fission products of NFC without isotopic separation will
increase the energy consumption, let alone the
opportunity to form new nuclides. These conditions can
lead to that in some of cases it may be more
advantageous to carry out the transmutation on isotopic
enriched targets.
We have shown in [6], that under irradiation of
nuclear fuel fission fragments with protons of an energy
less than 50 MeV, as a result of (p,xn yp) nuclear
reactions, the transmutation of long-lived nuclides in
short-lived ones and stable ones with summed
transmutation cross-section of about 1 barns. takes
place. So, at the energy of proton beam 20 MeV for
137Cs the following reactions giving stable or short-lived
nuclides take place:
137Cs (p, n) 137Ba; 137Cs (p, 2n) 136Ba;
137Cs (p, 3n) 135Ba;
137Cs (p, pn) 136Cs ⇒ (β- , 13 days) 136Ba;
137Cs (p, αn) 133Xe ⇒ (β-, 5,29 days) 133Cs;
The calculation of these reaction cross-sections
carried out using the statistical model of a compound
nuclei with taking into account the preequilibrium of
decay gives the summed cross-section of numbered
reaction equal to 1.03 barns.
Under irradiation of radioactive nuclei with a
particle beam of a fluence density ϕ, there are two
processes leading to decreasing the numbers of nuclei –
targets: process of a natural radioactive decay λ with a
decay constant and nuclear reactions transmuting the
initial nucleus in other nuclides with the cross-section σ
takes place. In this case the half-life period of an initial
nuclide looks as
T1/2 = ln2 / (λ + σϕ).
At a density of a 20 MeV proton beam on a
cesium target 2·1017 p/cm2s (about 32 mA/cm2)
T1/2=0.106 year is gained. As the initial quantity of 137Cs
(and 90Sr), contained in one ton of spent fuel exceeds in
1000 times the activity 1T of natural uranium, the time
of irradiation for reducing the activity in 1000 times is
10 T1/2, i.e. in this case it makes 1.06 years, that
corresponds to the optimum transmutation time, as it
was mentioned above.
The number of nuclei being transmuted during
the time t at the initial quantity No is
N = No [1 - exp (-σϕt)].
No is taken equal to the annual yield of 137Cs in 1000
MW WWER reactors (el.)i.e. 3.3·1026 nuclei. Then
under irradiation within one day we gain a number of
nuclei 137Cs equal to 5.8·1024. The daily yield of 137Cs in
this reactor makes - 9·1023 nuclei. Thus, such approach
allows, basically, transmutation of long-lived waste with
reprocessing of newly generated as well as and stored
waste.
The important moment is expenditure of energy
for transmutation.. In the mentioned proton energy
range the relation of probability of a nuclear interaction
resulting in transmutation, to ionization interaction
makes about 10-2, i.e. for transmutation of one nucleus
137Cs about 100 protons should be accelerated. Then
energy consumption for transmutation of one nuclei will
be Wexpen = 20·100=2 GeV.
As at fission of one nucleus 235U in the reactor,
the nucleus 137Cs is formed with a probability of 6·10-2,
the "useful" energy released in the reactor during
formation of one nuclei 137Cs is determined as
Wtot = 200/6·10 - 2=3.3 GeV. Taking into account the
efficiency of accelerator (< 50%) and of reactor (~30 %)
we obtain the ratio Wexpen/ Wtot.> 4.
The opportunity to decrease the energy
consumption for transmutation can be reached: in the
process of energy beam regeneration passed through a
target (in this case the thickness of a target should be
less than the run of the accelerated proton) for example,
using a ring of a type proposed by Ado [8], where after
passage of a target a beam is accelerated once more to
compensate the liberated energy, the realization of a
target in the form of the plasma having sufficiently high
density. The choice of the most acceptable way to
reduce the energy consumption is possible only after the
comparative analysis of above-mentioned opportunities.
CONCLUSION
The radioactive waste of the nuclear power
industry can be transmuted in stable isotopes, except for
group of actinides. For this one needs two groups of
accelerators: electronuclear breeding accelerators
(proton accelerators with the energy (1 - 1.5) GeV and
medium current 0.1A) and accelerators which can be
constructed today (proton accelerators with the energy
(100 - 300) MeV and medium current 0.001A).
However, only the monoisotopic targets can be
transmuted on accelerators, therefore, simultaneously
with accelerators high-performance radioactive waste
separators should be created.
REFERENCES
1. Steinberg M. V., Wotzak G., Manowitz B. Neutron
burning of long-lived fission products for waste
disposal. 1958, BNL-8558, Brookhaven Nat. Lab.,
Upton N. Y.
2. Gregory M.V. Steinberg M.V. A nuclear
transmutation system for the disposal of long-lived
fission product wastes. 1967, BNL-11915.
3. Wolkenhaner W.C. The controlled thermonuclear
reactor as a fission product burner. Trans. of the Am.
Nuclear Society. 1972, 15:1.
4. Claiborn H.C. Neutron-induced transmutation of
high-level radioactive waste. 1972, ORNL-TM-
3964, Oak Ridge, Tenessee.
5. Kostin V.Ja., Migalenja V.Ja., Shatnev M.G., L’vov
A. N. About «burn out» radioactive waste of
nuclideel fuel in a fluence of prompt neutrons " an
atomic Energy, 1981, 51, 5. P.336.
6. Kostin V.Ja., Migalenja V.Ja., L’vov A.
N.,Khizhnyak N.A. AS N950073, 704, 1982.
7. Blann M., Phys. Rev. Lett. 1972, v.28, p.757.
8. Ado Yu.M. et al. Trans. of V All-Union meeting on
charged particle accelerators, Vol..11, P.317, M.:
"Science", 1977.
116
CONCLUSION
References
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