**10. About possible scale of nuclear power engineering development**

Described actions sufficient using for fission materials reproduction in thermal reactor supplies besides high portion of raw uranium usage (up to 25% in contrast to ~1 % for thermal reactors with enriched fuel) small fuel requirement for core loading. Sum of these effects allows creation of world big nuclear power production industry.

Requirement in raw uranium and thorium of these reactors can be determined by formulae:

$$\mathbf{mU} = \mathbf{n}^\* \ \mathbf{t} \ \mathbf{\*} \ \begin{pmatrix} \mathbf{m}\_s \ \mathbf{"} \ \mathbf{Yu} \ \mathbf{"} \ + \ \mathbf{m}\_\mathbf{g} \ \mathbf{"} \ \mathbf{K}\_i \ \mathbf{"} \ \mathbf{Ku} \ \mathbf{/} \ \mathbf{2} \\ \end{pmatrix} \tag{12}$$

$$\text{mTh} = \text{n}^\* \text{ t}^\* \left( \text{m}\_s \text{ \* (1-\text{Yu})} \text{ \* } + \text{ m}\_g \text{ \* (1-\text{Ku}) / 2} \right) \text{:} \tag{13}$$

where:

212 Nuclear Power – Practical Aspects

fuel preparation.

*9.2.5. About nuclear safety* 

variants, works financing at NPP building.

for nuclear reactor with 80 MW thermal power.

which prevents power increase at reactivity accident [32].

At variant with common electrical supply network and absence of heat need (for example in the tropics) it is required to take into account turbine cost difference of first and second

In all case it should be noted, that NPP with 39% efficiency is more attractive than other small power NPP variants with efficiency up to 33%. Especially if we take into account many times lower raw uranium requirement and absence of uranium enrichment works for

On the base of described solutions heavy water gas cooled high power nuclear reactor can be built. Increase of core HWD leads to neutron leakage decrease, which is base neutron loss

Figure 15 shows coolant and moderator ducts scheme in heavy water gas cooled reactor,

**Figure 15.** Coolant and moderator ducts scheme in heavy water gas cooled reactor. 1 – reactor vessel, 2 – moderator, 3 – channel casing, 4 – fuel assembly, 5 – channel thermal isolation, 6 – integral coolant collector, 7, 8 – inlet and outlet of moderator, 9 – opening, which connects channel with collector, 10, 12

inlet and outlet of coolant, 11 – nozzle of accident drainage of moderator.

n – number of this type built reactor per annum;

t – time of nuclear power engineering development, years;

ms – mass of raw materials, needed for core loading;

Yu – raw uranium portion in fuel;

mg – fuel mass needed for year feeding of reactor;

Ki – portion of raw uranium usage in fuel cycle;

Ku – portion of raw uranium in feeding fuel.

Figure 16 shows development variant of power production with even power grow to the level of 8000 GW during 80 years with subsequent power level stabilization.

Work duration of thermal reactors with cheap uranium stocks at this power level and full raw uranium usage is ~2500 years. It is understandable that at such small raw uranium requirements is rational use of other more expensive deposits, where uranium stocks are much more than in cheap deposits.

Thermal Reactors with High Reproduction of Fission Materials 215

Fission materials reproduction possibility in different fuel types in ideal core without neutron losses in construction materials and leakage is shown. Equilibrium concentrations

Features of detailed regime campaign conduction (with fixed fuel location during all

Characteristics of loss and reproduction in case of CANDU and its possible modernization

Replacement in zirconium containing materials natural zirconium by isotope 90Zr and natural tin by isotope 120Sn, replacement of 7 fuel rods in fuel assembly with 37 fuel rods by beryllium insert for extra neutron production, change of fuel rods with oxide fuel by metallic fuel is considered as possible modernization directions, which supply high fission

Compound metallic fuel rod construction, placed in liquid metal heat transferring medium is suggested. Shape and small size of fuel rod ensure decrease of negative effect of swelling. Possibility of neutron loss decrease in CANDU from 5% to 2.8% in case of isotope modified

It is suggested that excess neutrons of detailed campaign beginning are used for fission materials reproduction. By the set of characteristics 233U is the best candidate for reproduction. Portion of raw uranium use increase in open fuel cycle up to 5.3% and full raw uranium

Conditions of high efficiency obtaining in Rankin cycle with heavy water gas cooled reactor are shown. Scheme of coolant ducts and steam loop of heavy water channel reactor with gaseous coolant, which ensures full use of neutron moderation energy, decrease energy loss for coolant pumping and obtaining high steam quality on the turbine exit. These actions allow to decrease cost for NPP creation, to have efficiency of 43 % taking into account

World nuclear power production industry creation with power of 8000GW to the end of XXI century on the base of suggested thermal reactors with high fission materials reproduction

Suggested technologies usage allows increasing world nuclear power industry to the end of XXI century with requirement decrease of natural uranium mining, proliferation danger

*Department of Development and Test of Reactor Devices, Institute of Atomic Energy of NNC RK,* 

zirconium and tin and to 1.7% in case of metallic fuel and beryllium insert.

usage in closed uranium and thorium fuel cycles is shown.

possible losses in core and steam cycle.

decrease comparing to fast reactors technology.

is shown.

**Author details** 

Vladimir M. Kotov

*Kurchatov, Kazakhstan* 

campaign) and compact regime (with staged spent fuel replacement with fresh fuel).

of fission materials in different fuel types are determined.

**12. Conclusion** 

variants are examined.

materials reproduction.

So, there is significant reserve in world nuclear power production industry.

**Figure 16.** Dependence of uranium and thorium requirements for different reactor types with zero initial power and its even increase up to level of 8000 GW with subsequent power level stabilization.
