VGB POWERTECH 5 (2021) - International Journal for Generation and Storage of Electricity and Heat

Abstracts VGB PowerTech 5 l 2021
The World’s first power plant to produce
400 billion kilowatt hours
Matthias Domnick, Sebastian von Gehlen,
Stephan Kunze, Gerald Schäufele,
Dietmar Schütze and Ralf Südfeld
When it first synchronised with the power distribution
network at 14:11 hrs on 5 September
1984, Grohnde nuclear power plant (KWG)
started to write its own success story. Since it
was first commissioned, the pressurised water
reactor has eight times been World Champion
in annual electricity generation. Even today,
Grohnde NPP still produces a good 12 % of the
electricity generated in Lower Saxony, thereby
helping to stabilize the electricity supply in
Germany. And yet another record was recently
added to this impressive list. On 7 February
2021, KWG was the first power plant unit in the
world to produce its 400 billionth kilowatt hour
of electricity. No other nuclear power plant unit
in the world has produced more electricity. This
amount of electricity would have supplied the
whole of Germany for nine months (based on
the 2019 figure of 512 TWh).
Quo vadis, grid stability?
Challenges increase
as generation portfolio changes
Kai Kosowski and Frank Diercks
The power generation portfolio in the German
high voltage transmission and distribution system
has been constantly changing since 2011.
After several decades with relatively constant
segmentation into base-, medium- and peakload
and a power plant park designed accordingly
for these purposes, significant changes
have occurred in the last 10 years. As an important
result of the so-called Energiewende , starting
in 2011 with the shutdown of the first German
nuclear power plants (NPP) after the reactor
accident in Fukushima, the last NPPs will
go eventually offline by the end of 2022. The
Coal Phase-Out Act of August 8th, 2020, a farreaching
edit with significance for the energy
industry in Germany, requires the shutdown of
all coal-fired power plants by 2038 at the latest.
From this point in time at the latest, there will
be no large, inductive power plants for generating
base load in the German power plant park.
Development of Safety-related residual
heat removal chains from german
technology pressure water reactors
(light and heavy water)
Franz Stuhlmüller and Rafael Macián-Juan
The Nuclear Power Plants (NPPs) with Pressure
Water Reactor for enriched fuel (PLWR,
Pressurized Light Water Reactor) and for natural
uranium (PHWR, Pressurized Heavy Water
Reactor), developed in Germany, are largely
identical in their basic design. However, there
is a striking difference in the scope of the main
reactor systems. While in PLWR these only
consist of Reactor and Reactor Coolant System
including Pressurizer and Pressurizer Relief
Tank, in PHWR the Moderator System is added.
In power operation of a PLWR, the entire thermal
reactor power is transferred to the water/
steam cycle via the Steam Generators. In PHWR,
on the other hand, part of the power (approx.
10 %) has to be removed - at a lower temperature
level - from the moderator, which is spatially
separated from the main reactor coolant
within the Reactor Pressure Vessel, but is kept
at the same pressure via function-related compensating
openings. This portion of power is
used to preheat the feed water before it enters
the Steam Generators. The Moderator System
installed for this purpose can also be used in a
second function as the inner link in the Residual
Heat Removal Chain (RHRC) for cooling the
reactor after it has been switched off. In PLWR
the analog system is operated exclusively for the
removal of residual heat from the reactor and,
if necessary, the fuel pool. In the following, the
development of the RHRC of both NPP lines is
shown and the main differences between both
NPP-types in this regard are explained by comparing
the most recently erected plants, DWR
1300 MW (KONVOI) and Atucha 2.
Demand analysis of nuclear power
technology in China: opportunities for
foreign nuclear power companies
Hong Xu, Tao Tang and Baorui Zhang
China has the largest number of nuclear power
plant (NPP) units under construction or
planned in the world, which shows the promising
potential business opportunities of its
nuclear power market. Simultaneously, it has
a complete nuclear industry chain with hundreds
of related companies/organizations. The
huge market of nuclear power is attractive to
foreign nuclear power companies. China has a
good environment for international cooperation.
But the problem is how to clarify the possible
demand in traditional sub-fields of nuclear
power technology and different subsidiaries for
cooperation. Due to the huge work of one-byone
demand analysis and the uncertainty of
the academic research level evaluation of the
subsidiaries from different organizations, this
article presents a statistical method based on
the evaluation of the China Nuclear Energy Association
(CNEA) experts and related reports.
The conclusion of this article can be used as a
reference for international cooperation in the
nuclear power community.
Error reduction in radioactivity calculation
for retired nuclear power plant considering
detailed plant-specific operation history
Young Jae Maeng and Chan Hyeong Kim
Accurate estimation of radioactivity distribution
at a retired nuclear power plant (NPP) is
important for establishing a reasonable dismantling
strategy and expecting radioactive
waste disposal costs for decommissioning. The
calculation of activity requires several input parameters,
including target nuclides, products,
irradiation history, and the neutron flux. To our
knowledge, in most cases, existing radioactivity
calculations for a retired NPP do not fully consider
the detailed plant-specific operation history,
including cycle-specific neutron flux data,
which may lead to significant errors. In this
study, we investigated the effect of using detailed
history on activity calculation. We calculated
the activities of samples in six surveillance
capsules of the Kori 1 NPP, using two approaches:
(1) considering and (2) not considering detailed
history. Activities calculated using these
two approaches were compared with measured
values to determine the improvement in accuracy.
The findings show that accuracy is significantly
improved when the detailed history is
considered. The average error of the calculated
activities was reduced from 12 %, 41 %, and
30 % to 5 %, 9 %, and 9 % for 63Cu(n,)60Co,
54Fe(n,p)54Mn, and 58Ni(n,p)58Co reactions,
respectively. The results of this study strongly
suggest that considering the detailed plant-specific
operation history is necessary in activity
calculation for a retired NPP.
Forum Energy Supply: Europe on the road
to a main disaster
After the lockdown, a blackout?
Herbert Saurugg
The European power supply system is undergoing
a fundamental upheaval where, above all,
“many cooks spoil the broth” applies. This is because
there is no overall systemic coordination
and approach. Each member country is making
its own energy transition in different directions
and there is hardly any coordinated approach
recognizable. In addition, fundamental physical
and technical conditions are being ignored and
replaced by wishful thinking, which is bound to
lead to disaster. This is because the power supply
system obeys purely physical laws. We still
have the opportunity to leave this fatal path.
Operating experience with
nuclear power plants 2020
VGB PowerTech
The VGB Technical Committee “Nuclear Plant
Operation” has been exchanging operating
experience about nuclear power plants for
more than 30 years. Plant operators from several
European countries are participating in
the exchange. A report is given on the operating
results achieved in 2020, events important
to plant safety, special and relevant repair, and
retrofit measures.
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