AREVA's Actiflo-Rad water treatment system for the

Inhalt | Content
Internationale Zeitschrift für
Kernenergie
5
Mai 2012 Offizielles Fachblatt der Kerntechnischen Gesellschaft
Fukushima Daiichi waste water treatment
scenario (from June to September 2011)
(Seite 308)
Ausschnitte des hybriden Rechengitters
(Seite 322)
Cover: Inspection of an emergency diesel
generator at the Santa María de Garoña NPP in
Spain. The current license for the 466 MWe gross
boiling water reactor will expire in 2013.
According to a new safety review of the facility in
2012 by the Spanish safety authority CSN, the
plant should operate for further 10 licensed years
until 2019 (Courtesy: Nuclenor)
A. Petersen 303 Grußworte zur
R. Güldner Jahrestagung Kerntechnik 2012
in Stuttgart
Content in brief 306
T. Prevost 308 Areva’s Actiflo TM -Rad
M. Blase Wasserbehandlungssystem für das
H. Paillard Kernkraftwerk Fukushima
H. Mizuno Areva’s Actiflo TM -Rad Water Treatment
System for the Fukushima Nuclear
Power Plant
W. Timpf 313 Lastwechselfähigkeiten von
M. Fuchs Kernkraftwerken – Erfahrungen
und Ausblick
The Load Follow Capability of Nuclear
Power plants – Experience and Outlook
F. Blömeling 318 CFD-Analysen in Aufsichts- und
P. Pandazis Genehmigungsverfahren
A. Schaffrath CFD Analyses in Regulatory Practice
J.-U. Klügel 325 Risikobeurteilung komplexer
Unfallszenarien
Risk Assessment of Complex Accident
Scenarios
C. Bühler 331 Sicherheitsanalytik für den Einsatz neuer
digitaler Sicherheits-Leittechniksysteme
Safety Analysis for the Use of New
Digital Safety I&C Systems
H. Bienia 337 Brennilis – Erster Einsatz von
Th. Noll Industrierobotern für den Rückbau eines
französischen Kernkraftwerks
Brennilis – First Use of Industrial Robots
in the Demolition of a French Nuclear
Power Plant
304 atw 57. Jg. (2012) Heft 5 | Mai

International Journal for
Nuclear Power
H. Völzke 343 Aktuelle Entwicklungen auf dem Gebiet
G. Nieslony der Behälter-Bauartprüfungen für das
V. Noack Endlager KONRAD
P. Hagenow Current Developments in Container
O. Kovacs Design Testing for the Konrad Repository
K. Büttner 347 Alternative Lösungen für Abfallbehand-
lungszentren bei Neubauten von
Kernkraftwerken (russischen Typs)
Alternative Solutions for Waste
Management Centres Designed for
New Nuclear Power Plants Under
Construction (Russian Type NPPs)
Redaktion 350 Tagungsbericht: Endlagerexperten trafen
sich in Essen – Reges Interesse am
1. Fachgespräch Endlagerbergbau von
DMT und GNS
Conference Report: Repository Experts
Met in Essen – Keen Interest in the 1st
Technical Discussion of Repository
Mining Organized by DMT and GNS
Redaktion 352 Kernenergie Online: Forschungsreaktoren
Nuclear Power On line: Research Reactors
Impressum 353
Nachrichten 353
Marktdaten 365
Veranstaltungshinweise 367
KTG-Mitteilungen 369
DAtF-Mitteilungen 370
atw 57. Jg. (2012) Heft 5 | Mai
Unfallmodell nach Bowtie
Inhalt | Content
(Seite 326)
Roboter mit Werkzeugmagazinen links und
oberhalb der Türöffnung zum Reaktorraum
(Seite 342)
Brüdenverdichter-Verdampfer der Firma LOFT
(Seite 349)
305

Content in brief
Areva’s Actiflo TM -Rad Water
Treatment System for the Fukushima
Nuclear Power Plant (Page 308)
T. Prevost, M. Blase, H. Paillard and H. Mizuno
In the wake of the March 11 th 2011 earthquake
and tsunami and the subsequent flooding of
several of the Fukushima Daiichi reactor units,
Japan and the Japanese utility Tepco faced a
crisis situation with incredible challenges.
Sea water and later desalted sea water used
for open circuit post-accident reactor cooling
accumulated in the basements of four reactor
buildings as well as in the basements of the
turbine buildings on the site. The water had
been heavily contaminated due to the fact that
it had been in contact with molten fuel assemblies
in the reactor cores. The water from
flooding and subsequent cooling needed to be
collected, along with rainwater. Despite the
use of additional water storage systems
brought to the site, a shortage of water storage
capacity was expected in a 3-month timeframe,
especially in view of the coming rain
season in Japan. The overall water inventory
was estimated at around 110,000 tons with a
contamination up to the order of 1 Ci/l
(3.7×10 10 Bq/l). To avoid an over-flow of highly
contaminated water into the sea Tepco envisaged
establishing a water treatment system.
This article focuses on the Actiflo-Rad
water treatment project implemented by Areva
as part of the Tepco general water treatment
scheme. It presents a detailed look at the functional
principle of the Actiflo-Rad process,
related on-the-fly research and development,
an explanation of system implementation
challenges and a brief summary of operation
results.
The Load Follow Capability of Nuclear
Power plants – Experience and
Outlook (Page 313)
W. Timpf and M. Fuchs
The notion that nuclear power plants are unflexible
machines that cannot be operated in
load-following mode has constantly been
spread by anti-nuclear activists over the last
years. But actually, the opposite is true. Nuclear
Power Plants are able to adjust their power output
over a wide range within a short period of
time. High power flexibility was already implemented
into the original design of German nuclear
power plants from the very beginning.
In the past, nuclear power plants demonstrated
their load-following capability for decades
in practice. But for many years, there was
no economic incentive and no technical need to
make use of this capability and thus, it was almost
forgotten. The situation has changed due
to the development of renewable energies.
Fluctuations in the offer from volatile energy
sources will cause an increasing need for the
flexibility of the power plant fleet. Just recently,
nuclear power plants were employed to balance
fluctuations in wind energy production. Since
nuclear power plants are highly flexible and do
not emit any carbon-dioxide, they are ideal
partners of the renewable energies.
CFD Analyses in Regulatory Practice
(Page 318)
F. Blömeling, P. Pandazis and A. Schaffrath
Numerical software is used in nuclear regulatory
procedures for many problems in the fields
of neutron physics, structural mechanics, thermal
hydraulics etc. Among other things, the
software is employed in dimensioning and designing
systems and components and in simulating
transients and accidents. In nuclear technology,
analyses of this kind must meet strict
requirements.
Computational Fluid Dynamics (CFD) codes
were developed for computing multidimensional
flow processes of the type occurring in
reactor cooling systems or in containments. Extensive
experience has been accumulated by
now in selected single-phase flow phenomena.
At the present time, there is a need for development
and validation with respect to the simulation
of multi-phase and multi-component flows.
As insufficient input by the user can lead to
faulty results, the validity of the results and an
assessment of uncertainties are guaranteed only
through consistent application of so-called
Best Practice Guidelines.
The authors present the possibilities now
available to CFD analyses in nuclear regulatory
practice. This includes a discussion of the fundamental
requirements to be met by numerical
software, especially the demands upon computational
analysis made by nuclear rules and regulations.
In conclusion, 2 examples are presented
of applications of CFD analysis to nuclear
problems: Determining deboration in the condenser
reflux mode of operation, and protection
of the reactor pressure vessel (RPV) against
brittle failure.
Risk Assessment of Complex Accident
Scenarios
(Page 325)
J.-U. Klügel
The use of methods of risk assessment in accidents
in nuclear plants is based on an old tradition.
The first consistent systematic study is
considered to be the Rasmussen Study of the
U.S. Nuclear Regulatory Commission, NRC,
WASH-1400. Above and beyond the realm of
nuclear technology, there is an extensive range
of accident, risk and reliability research into
technical-administrative systems. In the past,
it has been this area of research which has led
to the development of concepts of safety precautions
of the type also introduced into nuclear
technology (barrier concept, defense in
depth, single-failure criterion), where they are
now taken for granted as trivial concepts. Also
for risk analysis, nuclear technology made use
of methods (such as event and fault tree analyses)
whose origins were outside the nuclear
field. One area in which the use of traditional
methods of probabilistic safety analysis is encountering
practical problems is risk assessment
of complex accident scenarios in nuclear
technology.
A definition is offered of the term "complex
accident scenarios" in nuclear technology. A
number of problems are addressed which arise
in the use of traditional PSA procedures in risk
assessment of complex accident scenarios.
Cases of complex accident scenarios are presented
to demonstrate methods of risk assessment
which allow robust results to be obtained
even when traditional techniques of risk analysis
are maintained as a matter of principle.
These methods are based on the use of conditional
risk metrics.
Safety Analysis for the Use of New
Digital Safety I&C Systems
(Page 331)
C. Bühler
Age-induced replacement or modernization of
safety I&C systems by digital equipment technology
has been one of the topical subjects in
nuclear technology for more than a decade.
Digital equipment technology in this case
means microcontroller- or microprocessorbased
systems which implement I&C functions
in software (SW) and, on the other hand, systems
with programmed hardware (HW) components,
such as Application-specific Integrated
Circuits (ASIC), Field Programmable Gate
Arrays (FPGA) or Programmable Logic Devices
(PLS), which can be developed only by
means of sophisticated SW development environments.
The switch to digital equipment technology
is more than a mere change in equipment technology
even though the I&C functions remain
almost identical in most cases. The switch not
only leads to a different approach in equipment
qualification, but also requires new focal points
in plant design when it comes to assessing plant
design, and needs new or adapted methods of
analysis and evaluation. The main reason lies
in the greater possibilities of systematic errors
caused mainly by software-based development,
manufacture and maintenance. New and adapted
methods of analysis and evaluation for I&C
atw Vol. 57 (2012) No. 5
»atomwirtschaft-atomtechnik« is published
monthly by INFORUM GmbH,
Robert-Koch-Platz 4, 10115 Berlin, Germany
phone +49 30 498555-10
fax +49 30 498555-19
Publisher:
e-mail: atw@atomwirtschaft.de
Editorial:
e-mail: editorial@atomwirtschaft.com
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306 atw 57. Jg. (2012) Heft 5 | Mai

systems are presented and explained. It is safe
to say that safety I&C technology in the highest
category of requirements necessitates a
very far reaching realignment in design and
evaluation as well as the use of new analytical
techniques. This meets the claim of an I&C
technology fit for use, reliable and comparable
to the technology it replaces.
Brennilis – First Use of Industrial
Robots in the Demolition of a French
Nuclear Power Plant (Page 337)
H. Bienia and Th. Noll
A share of approx. 80 % nuclear electricity
makes France the country with the world's
largest proportion of nuclear electricity. A considerable
number of French plants were commissioned
more than 30 years ago. At the
present time, 58 nuclear power plants out of
this population are in operation, twelve have
already been decommissioned and are about
to be, or are being, demolished. France thus is
one of the most interesting and most dynamic
countries as far as future demolition projects
are concerned. Current demolition projects in
France have a kind of model or pilot character
for the future French demolition strategy and
are under particularly close supervision and
inspection by the operator, Electricité de
France. One of these projects is the current
demolition of the CO 2-cooled heavy water reactor
(EL 4) of Brennilis in Brittanny which
was decommissioned in 1985. Demolition of
the reactor, its primary system and ancillary
systems is handled by a Franco-German consortium
composed of ONET Technologies
Grands Projets, France, and NUKEM Technologies,
Germany.
Because of the special design features of
the Brennilis reactor and the boundary conditions
this created, it was not possible in many
cases to transfer directly German demolition
techniques.
The demolition technique adopted is based
on the use of remotely operated robot systems
not only performing disassembly but, step by
step, also building up infrastructure of their
own in the reactor compartment as demolition
progresses.
Besides the special technical features and
challenges arising in this project there are also
differences in licensing regulations and cultural
differences which play a major role. The
report concludes with a brief summary of experience
accumulated.
Current Developments in Container
Design Testing for the Konrad
Repository (Page 343)
H. Völzke, G. Nieslony, V. Noack, P. Hagenow
and O. Kovacs
In 2002, the Konrad repository was licensed as
a repository for radioactive waste generating
atw 57. Jg. (2012) Heft 5 | Mai
no heat. That permit subsequently became the
object of litigation and was confirmed by a
court of last resort as late as in 2007.
The Federal Office of Radiation Protection
(BfS) then started planning and converting
the former iron ore mine into a repository. The
licensed repository volume is 303,000 m 3
based on estimates of expected waste arisings.
The mine proper would offer a much larger
volume. However, cask emplacement can be
started only after completion of the repository
which, according to the present status, will
not be before the end of this decade.
Nevertheless, there is great interest even
now in conditioning and packaging for repository
storage of the radioactive waste planned
for Konrad, which also requires casks type
tested by the Federal Institute of Materials
Testing (BAM) and approved by the BfS. The
key items in the license for the repository are
comprehensive requirements to be met by
waste forms and casks. As far as continuous
revision of repository requirements and consideration
of materials hazardous to water
are concerned, it is assumed that the key requirements
applying to type tests of casks
with respect to waste forms and casks will be
affected by this either not at all or only very
slightly.
Alternative Solutions for Waste
Management Centres Designed for
New Nuclear Power Plants Under
Construction (Russian Type NPPs)
(Page 347)
K. Büttner
Today, designers of new VVER reactors as well
as companies operating Russian NPP favour
direct methods of waste management for
treating wastes of different categories generated
during plant operation. The objective is
to achieve the amount of 50 m 3 of conditioned
waste per 1 reactor unit per year,
which is currently being discussed internationally.
NUKEM Technologies has reviewed
the existing waste management concepts and
proposed improved waste management technologies.
The first step was to identify the waste prevention
policies. The waste management concept
focuses on subjecting different liquid
wastes to different treatment methods. Another
objective was to minimise the organic
content in conditioned waste. The treatment
methods for solid radioactive waste include
high force compaction and incineration. The
new concept also features a tracking system
which is used for classifying the incoming
waste and ensuring its traceable documentation
at different stages throughout the entire
treatment process. Additionally, each waste
package prepared for final storage is monitored
before it leaves the treatment building
and provided with an individual certificate
containing all data about the treated waste including
its radiological characteristics and the
place of storage.
Content in brief
Conference Report: Repository
Experts Met in Essen – Keen Interest
in the 1st Technical Discussion of
Repository Mining Organized by DMT
and GNS (Page 350)
The Editor
In mid-March 2012, more than 200 participants
met at the Essen technology service
provider's, DMT GmbH & Co. KG, for the
“1 st Essen Technical Discussion of Repository
Mining.” In cooperation with GNS Gesellschaft
für Nuklear-Service mbH of Essen,
DMT had invited to a lecture event about
this very topical subject. A new platform
was to be created for exchanges of experience
and discussions with colleagues in the field
and with representatives of the competent
authorities of the federal and state administrations.
The 5 lectures presented by Georg Arens
(Federal Ministry for the Environment, Nature
Conservation and Nuclear Safety – BMU), Dr.
Ute Blohm Hieber (Nuclear Power, Transport,
Demolition and Waste Management Unit of the
EU Commission – DG ENER-D.2), Matthias
Ranft (Federal Office of Radiation Protection –
BfS), Wilhelm Bollingerfehr (DBE Technology),
and Dr. Philipp Birkhäuser (Nationale Genossenschaft
für die Lagerung radioaktiver Abfälle
– Nagra, Switzerland) discussed both national
German and European as well as international
topics and aspects of final storage of radioactive
waste.
Nuclear Power On line:
Research Reactors (Page 352)
The Editor
Presentation of these contents in the World
Wide Web (WWW):
• Forschungsreaktoren MMM (Research
Reactors MMM): www.forschungsreaktoren.eu
• Forschungs-Neutronenquelle Heinz Maier-
Leibnitz FRM II: www.frm2.tum.de
• TRIGA Mainz: www.kernchemie.unimainz.de
• Helmholtz-Zentrum Berlin BER-II: www.
helmholtz-berlin.de/zentrum/grossgeraete/ber2/index_de.html
�
atw Vol. 57 (2012) No. 5
»atomwirtschaft-atomtechnik« is published
monthly by INFORUM GmbH,
Robert-Koch-Platz 4, 10115 Berlin, Germany
phone +49 30 498555-10
fax +49 30 498555-19
Publisher:
e-mail: atw@atomwirtschaft.de
Editorial:
e-mail: editorial@atomwirtschaft.com
www.atomwirtschaft.de
307

Water Treatment System for Fukushima
Als Folge des Erdbebens und des Tsunamis
am 11. März 2011 wurden mehrere der Reaktorblöcke
des Kernkraftwerks Fukushima
Daiichi überflutet. Japan und der japanische
Betreiber Tepco sahen sich daraufhin einer
Krisensituation mit unglaublichen Herausforderungen
gegenüber.
Meerwasser und später entsalztes Wasser,
das in einem offenen Kreislauf zur Reaktorkühlung
im Störfall verwendet wurde, sammelte
sich in den Untergeschossen von 4 Reaktorgebäuden
sowie den Maschinenhäusern
am Standort. Dieses Wasser war stark
kontaminiert, da es in Kontakt mit den geschmolzenen
Brennelementen in den Reaktorkernen
stand. Das Wasser aus der Überflutung
und der anschließenden Kühlung
musste, zusammen mit Regenwasser, gesammelt
werden. Trotz der Nutzung zusätzlicher
Speicher war ein Engpass bei der Wasserspeicherung
innerhalb von 3 Monaten zu erwarten,
insbesondere im Hinblick auf die kommende
Regenzeit in Japan. Das gesamte Wasserinventar
wurde auf rund 100.000 t geschätzt,
mit einer Kontamination bis zur
Größenordnung von 1 Ci/l (3,7×10 10 Bq/l).
Um ein Überlaufen dieses hoch kontaminierten
Wassers in das Meer zu verhindern, sah
Tepco vor, ein Wasseraufbereitungssystem
einzusetzen.
Dieser Beitrag berichtet über das von
Areva durchgeführte Actiflo TM -Rad-Wasseraufbereitungsprojekt
als Teil des allgemeinen
Wasseraufbereitungsschemas von Tepco. Detailliert
wird über das Funktionsprinzip des
Actiflo TM -Rad-Prozesses sowie die durchgeführte
kurzfristige Forschung und Entwicklung
informiert. Die Herausforderungen bei
der Systemimplementierung werden zusammengefasst
und die Betriebsergebnisse vorgestellt.
Anschriften der Verfasser:
Thierry Prevost and Michael Blase
AREVA NC
1, place Jean Miller
92084 Paris la Défense
France
Herve Paillard
Veolia Water
1 B, rue Giovanni Battista Pirelli
94410 Saint Maurice
France
Hisamatsu Mizuno
Veolia Water Japan
Yokoso Rainbow Tower 11F, 3-20-20 Kaigan,
Minato-Ku
Tokyo 108-0022
Japan
Areva’s Actiflo TM -Rad
Water Treatment
System for the Fukushima
Nuclear Power Plant
Thierry Prevost and Michael Blase, Paris/France,
Herve Paillard, Saint Maurice/France, and
Hisamatsu Mizuno, Tokyo/Japan
Introduction
In the wake of the March 11 th 2011 earthquake
and tsunami and the subsequent
flooding of several of the Fukushima Daiichi
reactor units, Japan and the Japanese utility
Tepco faced a crisis situation with incredible
challenges.
Sea water and later desalted sea water
used for open circuit post-accident reactor
cooling accumulated in the basements of 4
reactor buildings as well as in the basements
of the turbine buildings on the site.
The water had been heavily contaminated
due to the fact that it had been in contact
with molten fuel assemblies in the reactor
cores. The water from flooding and subsequent
cooling needed to be collected, along
with rainwater. Despite the use of additional
water storage systems brought to the site,
a shortage of water storage capacity was expected
in a 3-month timeframe, especially
in view of the coming rain season in Japan.
The overall water inventory was estimated
at around 110,000 tons with a contamination
up to the order of 1 Ci/l (3.7×10 10
Bq/l). To avoid an over-flow of highly contaminated
water into the sea Tepco envisaged
establishing a water treatment system.
The schedule had been extremely challenging:
Design, installation and commissioning
of the system were to be realised
within less than 3 months.
Global treatment scheme defined
by Tepco
Tepco decided to implement a water treatment
system which will be able to decontaminate
and to recycle the bulk of the water
used for cooling of the reactors with a
throughput of 50 m 3 /h, i.e. 1,200 m 3 /d.
For this purpose Tepco requested a multi
stage treatment process (Figure 1) to handle
the radioactive water consisting of:
Fig. 1. Fukushima Daiichi waste water treatment scenario (from June to September 2011).
308 atw 57. Jg. (2012) Heft 5 | Mai

Water Treatment System for Fukushima
• de-oiling
• pre-treatment
• decontamination
• desalinization.
The de-oiling stage had been supplied by
Toshiba, the pre-treatment stage based on
a Cs adsorption on zeolite by Kurion and
the decontamination based on a co-precipitation
by Areva in co-operation with Veolia
(ActifloTM -Rad system). The first desalinization
stage based on reverse osmosis
had been realised by Hitachi and the final
desalinization stage based on evaporation
had been realised partly by Toshiba and
partly by Areva in co-operation with Veolia
(supply of 3 evaporators with an overall
throughput of 100 m 3 /d).
ACTIFLO TM -RAD principles and
facility layout
Based on the Areva know-how related to
radionuclide precipitation from fuel cycle
plants in France, Areva considered the use
of the precipitation process for the decontamination
of the water. To deal with the
high flow capacity requested by Tepco
and the narrowness of potential installation
areas, Areva selected compact mixer
settlers from Veolia instead of a vessel cascade
as used in the fuel cycle plants in
France.
Contaminated water that passed through
the pre-treatment stage enters Actiflo TM -
Rad, which is a 2-stage process comprising
2 Veolia Water Multiflo TM and Actiflo TM mixer-settlers
units (Figure 2). In these units
the co-precipitation process developed by
Areva is implemented. It is used to decontaminate
so that the treated water can enter
the desalinization units.
The water is mixed with several reagents
in pre-contact tanks (2 40 m 3 tanks
for each treatment process stage) to capture
the different radioactive elements, so
that they can be recovered from the solu-
Fig. 4. Two-stage Actiflo TM -Rad process implemented in Fukushima Daiichi.
Fig. 3. Co-precipitation and flocculation principle.
Fig. 2. Actiflo TM -Rad: Decontamination by co-precipitation.
tions. Reagents used at Fukushima Daiichi
are nickel ferro cyanide (ppFeNI) to adsorb
cesium and barium chloride to precipitate
strontium as strontium sulfate in a mixed
crystal with barium sulfate.
The water is then transferred into the
mixer-settlers, which comprises four tanks.
The first one is the coagulation tank, where
the water is mixed with coagulant and undergoes
pH adjustment; in a second tank
the water can be mixed with micro sand and
in a third tank, the maturation tank, the water
is mixed with a polymer (Figure 3). All
these tanks are mechanically stirred.
The solid material settles to the bottom
of the fourth tank, the settling tank, while
the decontaminated water overflows into
storage tanks. A rack of inclined metal
plates, called lamella, is used to improve
the flocculated material separation from
water that flows across the plates. The Actiflo
TM -Rad process consists of two stages
of mixer settlers including upstream precontact
tanks (Figure 4).
The system had been implemented in
the radwaste building of Fukushima Daiichi,
including also other process parts
such as e.g. the waste water and waste water
retention tanks, treated water, sludge
and reagents storage tanks as well as a disc
filter (Figure 5 and Figure 6).
A part of the auxiliary equipment for the
Actiflo-Rad system, namely some of the
reagents storage tanks, including pumps,
310 atw 57. Jg. (2012) Heft 5 | Mai

Fig. 5. Layout of the Actiflo TM -Rad unit implemented in Fukushima Daiichi.
Fig. 6. Actiflo TM -Rad unit during installation in the radwaste building at Fukushima Daiichi.
pipes, valves and instrumentation had
been installed outside the radwaste building
(Figure 7).
The sludge had been discharged into a
concrete pit below the process area, which
had been equipped with an air bubbling to
avoid hydrogen accumulation, heat exchangers
to remove the decay heat and different
pumps for removal of sludge and supernatant
water. The reagents storage and
injection system had been realised outdoor
in front of the radwaste building. Outside
the radwaste building also further equipment
such as the process ventilation system,
air injection system for air bubbling of
the pit as well as for flushing the system it-
atw 57. Jg. (2012) Heft 5 | Mai
self to avoid hydrogen accumulation and
the cold water generation system had been
installed. Safety related measures had been
drawn up with redundancies respectively
diversification, e.g. for air bubbling using a
compressor and pressurized air cylinders.
Schedule for the implementation
As with the beginning of the rainy season
in Japan, Tepco expected an overflow of
contaminated water to the sea by mid of
June, the schedule had been extremely
challenging. Therefore the highest priority
had been to implement a water treatment
Water Treatment System for Fukushima
facility for recycling the treated water for
cooling of the reactors.
After a corresponding call of the Japanese
government on 27 th March (Figure 8),
Areva, within days, developed a specific solution
for Fukushima Daiichi, combining
Areva experience related to precipitation of
radionuclides with the Veolia know-how for
precipitation of pollutants for conventional
industrial waste water. Immediately laboratory
tests had been started for process verification.
These tests consisted in hot tests at
Areva’s La Hague site and CEA (Commissariat
à l’énergie atomique et aux énergies alternatives)
premises in Marcoule, to assure the
performance of the precipitation in the salty
water, as well as in cold tests at Veolia premises,
where the compatibility of the Areva
process with the equipment of Veolia had
been assured. Benefit had been taken from
the R&D led continuously by CEA and Areva
during many years on the precipitation process
to decontaminate radioactive liquid effluents.
For hot tests Fukushima Daiichi’s wastewater
had been simulated by mixing seawater
with boric acid and fission products from
La Hague recycling plant. Tests showed the
efficiency of nickel ferro cyanide (ppFeNi)
and barium chloride reagents to decontaminate
cesium and strontium from the salted
wastewater.
After the feasibility tests, a design optimization
R&D was conducted on a large
range of wastewater with different characteristics
(presence of chloride, high salinity,
pH, effluents temperature range from
20 to 60 °C) which proved that there was
no significant impact on the decontamination
factors for cesium and strontium. Collateral
benefits i.e. decontamination factors
on other radionuclides than cesium
and strontium were assessed (Ru ~10; Rh
~10; Eu ~100; Ce ~10; Am ~20; Cm ~2;
Ba-140 ~10). The optimal concentration of
each reagent in industrial configuration
with recycled sludge was determined. It led
to an optimization of the sludge quantities
by a factor 10 compared to the sludge production
in the La Hague tests. The optimal
contact time between waste waters and reagents
was determined (more than 1 hour)
for the design of the unit (leading to the installation
of pre-contact tanks).
The efficiency of coagulation in the Actiflo
TM -Rad process was assessed through
jar tests in Veolia laboratories in France
and Japan. These tests validated the compatibility
of Areva and Veolia reagents and
determined the settling speed and the turbidity
of supernatant. They proved that a
2-stage Actiflo TM -Rad would achieve a decontamination
factor on cesium between
1,000 and 10,000 and a decontamination
factor on strontium between 10 and 100.
Finally, pilot tests for the validation of the
chemical engineering were conducted in
311

Water Treatment System for Fukushima
Fig. 7. Actiflo TM -Rad unit: auxiliary equipment during installation outside the radwaste building at
Fukushima Daiichi.
Fig. 8. Overall schedule for Actiflo TM -Rad implementation at Fukushima Daiichi.
Veolia Kawasaki (Japan) plant on a 1/10
scale model.
The technical solution had then been
presented on 7 th April to Tepco.
During the following period, design and
equipment modification had been performed
by teams working in Europe and
Japan. At Areva, more than 200 engineers
had been working in Europe and more
than 20 engineers had been in Tokyo,
working 7 days a week, to co-ordinate the
interfaces with the third parties mentioned
above contributing to the project and with
Tepco.
Schedule was not the only issue: the activity
levels of the contaminated water,
outside of a crisis situation, would have required
the design and construction of a
dedicated building for the water treatment,
with remote operation and maintenance.
Instead the water treatment unit
was based on existing Actiflo TM and Multiflo
TM units that had to be dismantled from
the industrial site where they were used,
then modified in Veolia workshops and finally
installed in the radwaste building on
Fukushima site. This created added complexity
in the design and implementation.
Areva, Veolia as well as partner JGC (Japanese
Gasoline Company, responsible for
the installation and commissioning of the
Actiflo-Rad system) together with Tepco
and partners worked to design an emergency
unit, making the most of 3 keywords: robust,
simple, and efficient. The ALARA
principle (as low as reasonably achievable)
guided the adaptation of Actiflo TM equipment
to a nuclear environment: the equipment
was modified (e.g. valves were doubled,
replaced and/or moved) and shielded
to improve the maintainability of the unit
and limit the dose rate to workers. Each
maintenance operations have been studied
individually with maintenance experts
from La Hague fuel recycling plant, the goal
was to prepare guidelines to operators, and
assess the operator dose rate thus defining
the minimum amount of radiological
shielding.
For supervision of commissioning of the
system Areva deployed a team of 45 experienced
employees to Fukushima Daiichi,
supported by staff of Veolia Japan.
ACTIFLO TM -RAD operation
results to-date
Water decontamination at Fukushima Daiichi
is a success: the highly radioactive water
decontamination emergency facility
operated by Atox proved essential in Fukushima
Daiichi crisis mitigation. It prevented
any overflow or non-mastered release of
contaminated water to the sea.
As of 20 September, 2011 a total of
77,400 tons of highly radioactive water has
been decontaminated through the Actiflo
TM -Rad unit enabling a closed circuit
cooling of the Fukushima Daiichi reactor
units and used fuel pools with decontaminated
and desalted water (Table 1). The cesium
decontamination factor for the Actiflo
TM -Rad unit is above 10 4 .
Conclusion
Tab. 1. Operational results of the water treatment (September 2011).
Areva’s response to the Fukushima Daiichi
crisis was multi-phased: emergency aid and
relief supply was sent within days after the
312 atw 57. Jg. (2012) Heft 5 | Mai

accident; joint Areva and Veolia engineering
teams designed and implemented a
water treatment solution in record time,
less than 3 months; and Areva continues to
support Tepco and propose solutions for
waste management, soil remediation and
decontamination of the Fukushima Daiichi
site.
Despite the huge challenges, the Actiflo
TM -Rad project has been a success: the
water treatment unit started on time and
performed as expected. The performance
is the result of many key elements: Areva
expertise in radioactive effluents decontamination,
Veolia know-how in water
treatment equipments in crisis environ-
_____________________________________
Die Vorstellung, Kernkraftwerke seien unflexible
Maschinen, die nicht im Lastfolgebetrieb
eingesetzt werden können, wurde über
Jahre hinweg von Kernenergiegegnern verbreitet.
Doch tatsächlich trifft genau das Gegenteil
zu. Kernkraftwerke sind in der Lage,
innerhalb kurzer Zeit ihre Leistung über einen
weiten Bereich anzupassen. Ihre Lastwechselfähigkeit
ist nicht etwa das Ergebnis
nachträglicher Ertüchtigungen – Flexibilität
ist eine Eigenschaft der Kernkraftwerke, die
sie bereits seit ihrer Konstruktion besitzen.
In der Vergangenheit konnten die Kernkraftwerke
jahrzehntelang ihre Lastwechselfähigkeit
in der Praxis unter Beweis stellen.
Für viele Jahre gab es aber weder einen wirtschaftlichen
Anreiz noch die technische Notwendigkeit,
von dieser Fähigkeit Gebrauch
zu machen. Durch den Ausbau der erneuerbaren
Energien ist die Flexibilität der Kernkraftwerke
jedoch erneut in den Fokus gerückt.
Erst kürzlich wurden die Kernkraftwerke
zum Ausgleich der fluktuierenden Einspeisung
aus regenerativen Energiequellen
eingesetzt. Ihre hohe Flexibilität und ihre
CO 2-freie Stromerzeugung machen sie zum
idealen Partner der erneuerbaren Energien.
Anschriften der Verfasser:
Wolfgang Timpf
Sparte Kernkraftwerke
Leiter Anlagenbetrieb RWE Power AG
Huyssenallee 2, 45128 Essen
Dr. Michael Fuchs
Leiter Technik
E.ON Kernkraft GmbH
Tresckowstraße 5, 30457 Hannover
Überarbeitete Fassung eines Vortrags gehalten auf
dem VGB-Kongress „Power Plants 2011“, Bern/
Schweiz, 21. bis 23. September 2011. Mit freundlicher
Genehmigung des VGB PowerTech e.V.
atw 57. Jg. (2012) Heft 5 | Mai
ment, and of course Areva and Veolia
teams’ creativity. Benefit had been taken
from the R&D led continuously by CEA and
Areva during many years on the precipitation
process to decontaminate radioactive
liquid effluents. This success also had been
possible thanks to the involved Japanese
companies, JGC doing the installation,
ATOX operating the system, JNFL (Japan
Nuclear Fuel Limited) advising Tepco, Hitachi
and last but not least Tepco itself.
The project success is also due to Areva
and Veolia teams’ reactivity and high level
of commitment with engineering teams
working 24/7 in Japan, France and Germany.
Areva’s and Veolia’s deep knowledge
Water Treatment System for Fukushima
of the Japanese industry ensured that the
multi-cultural exchanges were not an issue.
Finally the excellent overall project
management and execution by Tepco and
other Japanese stakeholders as mentioned
above was very efficient.
The emergency water treatment was a
key step of the roadmap towards restoration
from the accident at Fukushima Daiichi
that Tepco designed and keeps executing
with success. Based on the experience
gathered during the crisis Areva is in the position
to offer mobile treatment units for
waste water in emergency situations, based
on the Actiflo TM -Rad principle but also
based on adsorption on solid adsorbents. �
Lastwechselfähigkeiten
von Kernkraftwerken –
Erfahrungen und Ausblick
Wolfgang Timpf, Essen, und Michael Fuchs, Hannover
Einleitung
Eine Behauptung, die in regelmäßigen Abständen
von Kernenergiegegnern kolportiert
wird, lässt sich etwa folgendermaßen
zusammenfassen: „Kernkraftwerke sind
träge Grundlastkraftwerke und verstopfen
die Netze.“ Beispielsweise schrieb im Juni
2009 das damals noch von Sigmar Gabriel
geführte Bundesministerium für Umwelt,
Naturschutz und Reaktorsicherheit:
„Kraftwerke, die die Schwankungen der
Energiegewinnung aus Wind und Sonne
ausgleichen sollen, müssen vor allen Dingen
eines sein: flexibel. Atomkraftwerke
sind jedoch genau das Gegenteil, nämlich
unflexibel und nur begrenzt regelbar. Sie
sind dafür konstruiert, möglichst gleichmäßig
mit 100 % Auslastung zu fahren,
also immer gleich viel Strom zu produzieren
– unabhängig davon, ob er gebraucht
wird oder nicht“ [1].
Unter all den kuriosen Mythen, die sich um
die Kernenergie ranken und bei Experten
Kopfschütteln hervorrufen, nimmt dieser
eine Sonderstellung ein, denn tatsächlich
Kernkraftwerksbetrieb: Lastwechselverhalten
trifft genau das Gegenteil zu. Kernkraftwerke
gehören zu den flexibelsten Anlagen
im Kraftwerkspark. Insbesondere die deutschen
Kernkraftwerke sind hochflexibel
und konnten ihre Fähigkeiten sowohl unter
Testbedingungen als auch in der Praxis
unter Beweis stellen.
Vor dem Hintergrund der im Jahr 2010
beschlossenen Laufzeitverlängerung erlangte
das Thema besondere Bedeutung.
Mit Blick auf die europäischen Klimaziele
erschien ein zukünftiges Zusammenspiel
der Kernkraftwerke mit den erneuerbaren
Energien als ideal. Die Kernkraftwerke hätten
auch bei einem hohen Anteil erneuerbarer
Energien die Möglichkeit, Schwankungen
in der volatilen regenerativen Einspeisung
auszugleichen und damit eine sichere,
bezahlbare und CO 2-freie Stromversorgung
zu gewährleisten. Durch die mit
der 13. Novelle des Atomgesetzes beschlossene
Rücknahme der Laufzeitverlängerung
und vorzeitige Abschaltung der Kernkraftwerke
wird dies nur in begrenztem Maß
möglich sein. Dennoch bleibt das Thema
aktuell und soll im Folgenden näher beleuchtet
werden.
313

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