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<strong>atw</strong> Vol. 63 (<strong>2018</strong>) | Issue <strong>10</strong> ı October<br />

Laser Cutting for Nuclear Decommissioning:<br />

An Integrated Safety Approach<br />

Howard Chapman, Stephen Lawton and Joshua Fitzpatrick<br />

Introduction Laser cutting has been proposed as a method of size-reduction of active materials for operations such<br />

as nuclear decommissioning. Laser cutting combined with semi-automated control is faster and far more efficient than<br />

conventional cutting techniques and will produce less secondary waste.<br />

The key potential benefits over traditional<br />

cutting methods in terms of<br />

reducing the risk to As Low As Reasonably<br />

Practicable (ALARP) include:<br />

• Narrower kerf widths than traditional<br />

hot cutting methods, resulting<br />

in reduced dross and fumes,<br />

leading to less radioactive contamination<br />

and waste.<br />

• No vibration transferred into the<br />

waste piece which could mobilise<br />

contamination.<br />

• Less thermal energy imparted<br />

into the cut materials than other<br />

hot cutting methods, therefore<br />

reducing the risk of volatilising<br />

contamination.<br />

• No consumables required for laser<br />

cutting, which generate secondary<br />

waste.<br />

The use of laser cutting is a mature<br />

technology in widespread use in other<br />

industries and the modular design<br />

offers the capability of being scaled<br />

to meet nuclear requirements and<br />

remote deployment. During cutting,<br />

there are no reaction forces and<br />

cutting can be achieved on difficult<br />

shapes. The cutting tool is lightweight<br />

and the equipment has good tolerance<br />

to stand-off control which is a great<br />

benefit for remote operations in active<br />

areas.<br />

The NNL robot controlled laser<br />

cutting demonstration facility is a first<br />

| | Fig. 1.<br />

NNL Robot Controlled Laser Cutting Facility.<br />

of a kind full-scale replica of an<br />

existing active handling enclosure<br />

operated by NNL. The replica demonstration<br />

facility has recently been<br />

constructed at the NNL Preston Laboratory<br />

and is claimed to be the world’s<br />

most advanced per manent robot<br />

controlled laser cutting system in an<br />

active nuclear environment.<br />

Major world first achievements by<br />

NNL’s demonstration facility include<br />

the integration of an air-cooled laser<br />

head in an active environment; point<br />

cloud data acquisition on an industrial<br />

robot and a semi-automated system<br />

that provides path planning and executes<br />

a cut without teleoperations.<br />

NNL’s Robot Controlled Laser Cutting<br />

Facility employs an industrial<br />

robot arm with a 5kW infra-red laser<br />

equipped with a series of two fibre<br />

optic cables connected in series, and an<br />

air-cooled laser cutting head. The facility<br />

is equipped with a Local Exhaust<br />

Ventilation (LEV) system and has been<br />

used to perform a variety of novel trials<br />

to provide unique information on fume<br />

generation. The results of the active<br />

experiments on fume generation from<br />

NNL’s Robot Controlled Laser Cutting<br />

Facility, will allow aleatory and epistemic<br />

uncertainties when using lasers<br />

within decommissioning environments<br />

to be refined and disseminated to the<br />

wider nuclear industry.<br />

This paper provides an overview of<br />

the production of an integrated fit for<br />

purpose safety case for NNL’s Robot<br />

Controlled Laser Cutting Facility starting<br />

with consideration of regulatory<br />

requirements from a United Kingdom<br />

(UK) perspective. The safety case for<br />

the facility is based upon on a robust<br />

defence in depth Hazard Management<br />

Strategy (HMS) which has been used<br />

to identify safety measures which are<br />

proportionate to hazard severity. The<br />

development of an integrated safety<br />

case approach for the facility has enabled<br />

the often competing needs of different<br />

hazard disciplines to be harmonised<br />

and managed.<br />

Figure 1 shows a Computer Aided<br />

Design (CAD) model of NNL’s Robot<br />

Controlled Laser Cutting Facility.<br />

Assessment of hazards<br />

Regulation and legal<br />

requirements<br />

The civil nuclear industry worldwide<br />

is regulated to ensure that activities<br />

related to nuclear energy and ionising<br />

radiation are conducted in a manner<br />

which adequately protects people,<br />

property and the environment.<br />

In the UK, the Office for Nuclear<br />

Regulation (ONR) is the agency<br />

responsible for the licensing and<br />

regulation of nuclear installations<br />

and the legal framework for the<br />

nuclear industry is based around the<br />

Health and Safety at Work Act<br />

( HSWA) [1], the Energy Act, [2] and<br />

the Nuclear Installations Act (NIA),<br />

[3].<br />

A fundamental requirement cited<br />

in UK legislation is that risks be<br />

reduced to ALARP. This principle<br />

provides a requirement to implement<br />

proportionate measures to reduce risk<br />

where doing so is reasonable. The<br />

ALARP principle is applied by<br />

adhering to established good practice,<br />

or in cases where this is unavailable,<br />

it is applied to demonstrate that<br />

measures have been implemented<br />

up to the point where the cost of<br />

additional risk reduction is disproportionate<br />

to the benefit gained.<br />

521<br />

DECOMMISSIONING AND WASTE MANAGEMENT<br />

Decommissioning and Waste Management<br />

Laser Cutting for Nuclear Decommissioning: An Integrated Safety Approach ı Howard Chapman, Stephen Lawton and Joshua Fitzpatrick

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