Moisture Separator Reheater - Balcke-Dürr Energietechnik Gmbh

Moisture Separator Reheaters
Figure 12. Fin tube.
cases including the valve tests had been carried
out without any difficulties and the reheater
had been repeatedly inspected.
The deformation of the baffles could be attributed
to a special load point which had not
previously been taken into account (idling at
2 % load with reheater connected). The support
structure for the reheater was therefore
reconstructed when the fuel elements were replaced
in June/July 1980. The reheater bundles
were removed from the vessel and returned
to the works in order to carry out the
reconstruction. The side plates of the bundles
were separated from the baffles and replaced
by new side plates. In doing this the construction
was changed in such a way that in intermittent
load cases the relative motion occurs
between the side wall and the baffle and not
between the tube and baffle as was previously
10
the case. The whole reconstruction including
the dismantling and installation of the bundles
was carried out within the period of 8 weeks
scheduled for replacing the fuel elements.
Based on the available operating experience
this reconstruction has proved its worth.
When the tube bundle was removed the initial
flow side became accessible: this cannot
be inspected when the bundle is installed.
Local red-brown deposits were found ( F i g -
u r e 1 1 ) . These deposits could be removed
without any difficulty using a steel brush. The
other tube surfaces were covered with a thin,
dark grey magnetic layer which had formed
naturally as a protective layer (F i g u r e 1 2 )
contrary to the red-coloured foreign deposits
which occurred locally. Part of the red-brown
deposits was removed; analysis showed it to
be hematite. There was no erosion whatsoever
Figure 13. Fine separator column. Figure 14. Erection of the reheater.
on the fins although at Gösgen-Däniken the
separators are overloaded during intercept
valve test cases and water is therefore entrained
into the reheaters for short periods.
The fin tube baffles are sometimes mounted
on the non-finned intermediate parts and
sometimes on the fins. Both methods have
been proven effective.
1300 MW Standard MSR for
NPPs Grohnde and Philippsburg 2
The design can be seen from Figure 7. The
separator and the reheater are arranged above
one another in the vessel shell. The separators
consist of a preliminary separator (coarse separator)
and the main separator. The steam entering
through the lower nozzles is directed to
the base plate in the coarse separator, where
spray water entrained in the steam is separated
and drawn off under the base plate. The steam
is then redirected and flows upwards in the
inlet channel to the fine separators. The internal
cylinder is equipped in such a way that the
velocity is regulated as evenly as possible over
the cross-section of the inlet channel.
The steam from which the spray water has
been removed now flows to the star-shaped
fine separator arranged in three levels above
one another. Perforated sheets are arranged in