qualifcation are essential
activities for the nuclear
industry to demonstrate
that new and existing
plant equipment will
operate safely in all
conditions and also
shut down safely in fault
New nuclear power plants cost up to $25 billion to build. But, midway through constructionoronceupand running, they could suffer considerabledelaysoreven
temporary shutdowns because of a fault in a
seemingly insignifcant sub-assembly item.
For example, the pumps and valves
essential for safe operation of the cooling
system rely on elastomer ‘O’ ring seals to
maintain the equipment’s integrity. If these
seals fail, they could curtail the operation of
the plant or signifcantly delay its life extension.
To mitigate this risk for reactor vendors and
operators, Amec Foster Wheeler has carried
out extensive accelerated ageing tests on
‘O’ ring seals by simulating the wear and
tear caused by heat, mechanical stresses
and radiation, as well as accident conditions.
Batch testing of these easily overlooked
ancillary items revealed discrepancies in
manufacturing quality and a wide variance in
This underlines the importance of
equipment qualifcation (EQ) and materials
qualifcation (MQ). They are essential activities
for all high integrity industries, not just nuclear,
to demonstrate that new and existing
plant equipment, whether mechanical,
electromechanical, electrical or electronic, will
operate safely in all conditions and also shut
down safely in fault conditions.
In the nuclear industry, EQ is a regulatory
requirement which must be satisfed in order
to obtain and maintain a licence to operate.
Failure to carry out EQ programmes that
meet expected standards and relevant good
practice can lead to signifcant delays, which
in turn may drive up the cost of commissioning
new plants or resuming operations.
EQ is often considered as a qualifcation
process to establish that a manufactured
component or system is ft for purpose. In fact,
the EQ process is fully applicable from design
and materials selection right through to life
extension. The International Atomic Energy
Authority (IAEA) defnes this lifecycle as the
‘Four Phases of EQ’ (see Figure 1).
Incorporating EQ requirements into the
design stage will inevitably help ensure that
downstream EQ programmes go to plan and
that equipment qualifes right frst time.
EQ assessments, tests and justifcations can
take many months to complete and so early
EQ planning is essential. Testing programmes
typically include thermal, climatic and
mechanical tests as well as irradiation,
seismic and electromagnetic compatibility
(EMC) testing. Thermodynamic accident
condition testing, such as for loss of coolant
accidents (LOCA) or high energy line breaks
(HELB), is also typically required, either on the
component or full scale equipment level.
EQ programmes can often be optimised
by testing families of components, grouping
similar equipment and components with
similar functionality and materials, so that one
piece within the family can be tested and
justifed as representative of the entire family.
Although a lot of work is required to group a
family accurately, the time and effort invested
Design Process Materials selection, component/equipment design
Establishing EQ Component/equipment environmental testing
Preserving EQ Maintenance schedule, technical specifcation for operation, condition monitoring
Upgrading EQ Extension of component life through materials testing