atw 2018-05v6

inforum

atw Vol. 63 (2018) | Issue 5 ı May

suggestions from European Utility

Requirements (EUR), WENRA safety

reference levels, and IAEA introduction

of the DEC term and concept into

the safety standards series. Examples

of a use of this approach for Dukovany

and Temelín safety analyses have been

presented.

The programme for severe accidents

for Czech NPPs is very extensive,

this contribution included mainly the

activities related to the Temelín NPP,

but also the Dukovany NPP has own

program and activities related to the

topic of severe accident. The common

for both NPPs and not yet mentioned

is the training of the staff. The UJV

supports both NPPs for longer time

with special lessons on the progress of

the severe accident and impact of an

application of measures to the SA

course. Recently the new tool for the

training is close to the completion, it is

named VINSAP (Visualization of NPP

Severe Accident Progress for Training

on SAM), the project is sponsored

by the Technology Agency of Czech

Republic (project no. TH01011086).

References

[A]

National Report on “Stress Tests” of NPP

Dukovany and NPP Temelín, Czech

Republic, December 2011.

[B]

[C]

Authors

National Action Plan (NAcP) on

Strenghtening Nuclear Safety of

Nuclear Facilities in the Czech Republic,

State Office for Nuclear Safety, rev2,

Jan 6, 2015.

SUJB directive BN-JB-1.7, Selection and

Assessment of Design and Beyond

Design Events and Risks for Nuclear

Power Plants, 2010.

J. Duspiva

J. Holy

P. Kral

M. Patrik

UJV Rez, a.s.

Hlavni 130

25068 Rez, Czech Republic

E. Hofmann

CEZ, a.s.

Duhova 2

14000 Prague, Czech Republic

Applications of Underwater-Robotics

in Nuclear Power Plants

OPERATION AND NEW BUILD 305

Gunnar Fenzel, Dr. Dietmar Nieder and Alexandra Sykora

1 Research project AZURo Cutting and packing of the reactor pressure vessel (RPV) is one important step

during decommissioning of nuclear power plants. The RPV and its internals are radiological activated caused by the

long standing neutron flux.

In particular the internals which –

amongst others – retained the fuel assemblies

have to be cut and packed

under water due to their high radiological

activity. In the past this was

largely done manually using remote

handled tools (such as rods, grippers

and cranes). The operation of the

remote handled tools is time consuming

and enables access to the respective

parts by one direction only. Thus

the accessibility is strongly restricted

slowing down the progress of the

work. Hence the costs of the decommissioning

are highly increased. In

addition, the risk of failures is

enlarged by the inflexibility of the

tools. Moreover and due to the

complex proceeding, the workers

are exposed to a certain radiation

level leading finally to an averaged

increased radiation exposure.

Therefore, it was the objective of

the research project Automated Cutting

of Reactor Pressure Vessels Internals

Using Underwater-Robotics (AZURo) to

(semi-) automate frequently repeated

activities by an underwater robot.

This joint research project was

sponsored by the German Federal

Ministry of Education and Research

(BMBF). It was executed together with

Fraunhofer-Einrichtung für Gießerei-,

Composite- und Verarbeitungstechnik

IGCV. The project AZURo started in

2012 and was finished in 2016.

The highest degree of innovation is

given in the research of the application

of industrial robot systems under

water and in radiation fields. Thereby

there is no direct contact possible,

neither with the robot itself nor with

the workstation. All works at the

system have to be performed remotely

monitored respectively remotecontrolled.

Key aspects of the development

were remote control of the

system, optical monitoring and the

development of an intuitively

designed simulation ambience with

automated path planning.

Arm of robot

Total mass

max. load

The system supports the operator in

planning and execution as well as in

handling steps but ensures the control

of a human being at all times. Just as

well the nuclear requirements such as

intervention capability, reproduc ibility

and health physics aspects during

developing have to be con sidered.

2 Advantages of AZURo

The (semi-)automation of cutting and

packing activities by means of robots

will lead to

• a reduction of the local radiation

exposure of the involved staff,

• a shortening of the performance

times of cutting and packing of

highly activated components,

• a lowering of costs for such projects,

and

Approx. 1,100 kg

150 kg

Protection class IP 68

Working space (spherically) without tools, max.

Working space (spherically) with tools, max.

| | Tab. 1.

Technical Data.

Ø 2,194 mm

Ø 2,764 mm

Operation and New Build

Applications of Underwater-Robotics in Nuclear Power Plants ı Gunnar Fenzel, Dr. Dietmar Nieder and Alexandra Sykora

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