196
PGV-1000M was mainly designed on the basis of the following requirements to
steam generators for NPP (Fig. 4.6):
•
the manufacturing techniques shall be mature (all processes shall be thoroughly
developed and tested); the steam generator shall provide for an effective heat removal
from the reactor at a minimum vertical drop between the reactor and steam generator; and
it shall provide for cooling the coolant to adequate temperatures in all anticipated condi-
tions;
•
the design shall provide for a separate line for redundant feed-water supply to the
steam generator;
•
the overall dimensions shall be limited so as to provide for the railway transpor-
tation;
•
the design shall exclude any possible overflow from one circuit into the other (the
standard flow-over rate is 5 L/h).
The steam generator was designed in compliance with all the requirements listed
above.
PGV-1000M steam generator is a horizontal single-unit steam generator with a tub-
ular surface submerged into the secondary water, integrated steam separators, a feed-water
discharge system, a steam header, a submerged perforated sheet, and an emergency feed-
water discharge system.
The steam generator consists of the following units shipped separately: two sup-
ports, one steam header, and one pipe with a spacer. Further, the standard steam generator
set includes a set of embedded fittings, field check couplings and mounting spare parts.
The steam generators are arranged in pairs in tightly sealed boxes. Each steam gen-
erator is mounted on two supports. In order to prevent a dynamic movement (e.g., in
earthquakes), the steam generators are supported by hydraulic shock absorbers.
The steam generator weighs 694 tons (as shipped) with the supports and 322 tons
without the supports. The steam generator with the supports and with both the primary and
secondary circuit filled weighs 842 tons (without thermal insulation).
The configuration of the steam generator with eight hydraulic shock absorbers was
developed to withstand earthquakes with the magnitude up to 9 and to operate in the tropi-
cal climate. Basic specifications of PG-1000M are provided in Table 4.1.
The steam generator consists of the following components and major units:
•
a vessel;
•
a heat exchange surface (of the tube bundle);
•
a «hot» and «cold» header;
•
a louver separator;
•
a primary feed-water discharge unit;
•
an emergency feed-water discharge unit;
•
a steam load equalizer (a submerged perforated sheet);
•
supports and hydraulic shock absorbers;
•
level gauges measuring fluid level in the steam generator (leveling vessels, tie-
ins, and pulse lines);
•
purge and drain lines.
PGB-1000M vessel is a welded cylindrical vessel taking up pressure of the second-
ary circuit. The vessel consists of a cylindrical portion formed by three shells of different
thickness, and an elliptical bottom. Manways are arranged in both ends of the vessel – the
manways are intended for the maintenance and repair of in-vessel equipment of the steam
generator.
