1. Give equivalents to the terms on the fig.2 using technical dictionaries.

Be ready to talk about the general design and operation of a fission reactor.

2. Translate into Russian:

Sodium reactor: To enable a nuclear reactor to give off its heat at the highest pos­sible temperature and yet avoid the need for a thick-walled pressure vessel, a substance with a low melting point and a high boiling point can efficiently be used as the heat- transfer medium. A suitable substance for the purpose is the metal sodium. There are, however, some unavoidable drawbacks associated with its use. For this reason, with a sodium-cooled reactor the heat exchanger cannot be directly connected to the primary circuit; a secondary circuit must be interposed. This prevents radioactive material from coming into close proximity to the water that is to be converted to steam. Sodium is usually employed as the coolant for the secondary circuit also. Another problem associ­ated with the use of sodium is its reactivity with water and with atmospheric oxygen. Besides, the presence of even small amounts of sodium dioxide in the heat-transfer me­dium (coolant) causes a significant increase in corrosive attack of the stainless steel used as the construction material for those parts which come into contact with the sodium.

In comparison with moderator materials, sodium has a relatively large initial cross sec­tion for neutrons; for this reason it is necessary to take special precautions to prevent an escape of the sodium from the reactor core and thus avoid a sudden intensification of the chain reaction.

1. Translate into Russian:

In a typical boiling water reactor the reactor core creates heat and a single loop both delivers steam to the turbine and returns water to the reactor core to cool it. The cool­ing water is force-circulated by electrically powered pumps. Emergency cooling water is supplied by other pumps, which can be powered by onsite diesel generators. Other safety systems, such as the containment building air coolers, also need electric power.

The core of the reactor is a cylinder 1350mm long and 1570 mm in diameter. The core consists of hexagonal assemblies that are all cooled and enclosed in individual coolant tubes. There are driver fuel, blanket, GEM, control rod, reflector, and USS as­semblies (these assemblies are described following this card). The average power den­sity over the entire core is 180 kW/L. The core can run two years between refuelings and each reactor will only be out of service for 18 days. Refueling is accomplished using the In-Vessel Transfer Machine.

The reactor vessel is a cylinder 18.7 m long and 5.7 m in diameter. It will be made of grade 316 stainless steel. The reactor vessel contains the core and most of the reactor components submerged in liquid Sodium. The space above the Sodium but below the top of the reactor vessel is filled with Helium at atmospheric pressure. The core sits in the very bottom of the vessel.

2. Translate the following information into Russian:

The NRC standard is “as low as reasonably achievable” but no more than 25 mil- lirem a year in additional radiation (above the background exposure in that area) to the average member of a critical, or vulnerable, group. The Environmental Protection Agency has a standard for sites that are chemically contaminated, based on a one-in- a-million chance of an additional cancer. It works out to 15 miliirem per year, with no more than four miliirem of that amount coming from groundwater.

The miliirem is an odd unit to get a handle on. It is not directly a unit of radiation but one of biological damage. It derives from the roentgen, a measure of the ionizing power of gamma rays. But the three dominant types of radiation - alpha, beta and gam- ma-differ in their biological potency; the rem, which is short for “roentgen equivalent man,” integrates the three into a single number.

The NRC asserts that its standard is sufficiently protective. Arguably, 25 miliirem and 10 miliirem are effectively the same. Worse, the significance of even 25 miliirem is largely unknown. The idea that this amount has a health effect is part of a crucial but unproved assumption about radiation exposure - that unlike many chemical hazards,

there is no threshold below which it is harmless. In fact, the mathematical model used to draw up safety regulations assumes that a given increment of exposure, 10,000 ner- son-rem of collective dose, will cause one to eight fatal cancers no matter how applied. This is in contrast to individual dose; without medical treatment, a dose of about 350 rem will kill half of those exposed in what the regulators call “prompt death,” as op­posed to the “latent cancer fatalities” from collective doses.

The average American’s annual dose from all sources, including cosmic rays, ra­don gas and medical x-rays, is about 360 miliirem. That would mean that 25 miliirem from a decommissioned nuclear reactor is nearly an additional one-month dose every year.