Office for Nuclear Regulation

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Summary of the regulations for spent nuclear fuel pools design and operation

Date released
11 December 2019
Request number
Release of information under
Freedom of Information Act 2000

Information requested

I am requesting a summary of the regulations for spent nuclear fuel pools design and operation.

Information released

We can confirm that, following a review of our paper and electronic records, ONR does not hold a summary of the regulations for spent nuclear fuel pools design and operation that you have requested. However, you may find the following information useful.

The term “regulation” has a particular legal meaning in the UK. Regulations are secondary legislation published under powers given to ministers from an Act of Parliament. Regulations provide practical measures that enable the law to be enforced. The response provided to your question identifies key regulations.

However, it also identifies other codes, standards and guidance that are relevant. The response is in three sections, which relate to three different aspects of fuel ponds:

  1. Civil Engineering -The structure of the pond
  2. Mechanical Engineering -The operation of plant and equipment around the pond
  3. Chemical Engineering - Control of the chemistry of the pond water

Civil Engineering

From a civil engineering perspective, the key safety functions for spent fuel storage ponds are that the pond water is suitably contained and sufficient radiological protection is provided against the hazard posed by the stored fuel. The radiological protection provided by the pond must comply with the requirements of the Ionising Radiation Regulations 2017 (IRR17) . This, among other requirements, imposes annual radiological exposure limits upon workers in the vicinity of the pond. This is usually achieved by maintaining a minimum depth of water above the spent fuel, in combination with the walls and base of the pond. IRR17 must be complied with throughout operation of the pond.

There are no specific regulations relating to the civil engineering design of a spent fuel storage pond. All Nuclear Licensed sites have a suite of 36 Licence conditions set out in ONR's Licence condition handbook which the dutyholder (Licensee) must comply with. Licence Condition 34 requires that “the licensee shall ensure, so far as is reasonably practicable, that radioactive material and radioactive waste is at all times adequately controlled or contained so that it cannot leak or otherwise escape from such control or containment.” Expectations of how this requirement is achieved are expanded within ONR’s Safety Assessment Principles and Technical Assessment Guides , in particular the Civil Engineering Containments for Reactor Plants Assessment Guidance (T/AST/020).

The requirements relating to the civil engineering design of spent fuel storage ponds include:

Mechanical Engineering

Mechanical Engineering considerations are around lifting equipment to move fuel in and out of the pond, and equipment such as pumps and filters which control the condition of pond water. Lifting equipment is covered under the Lifting Operations and Lifting Equipment Regulations 1998 (LOLER). Other mechanical equipment is covered under the Provision and Use of Work Equipment Regulations 1998 (PUWER). It is possible that if certain chemicals were used then the requirements of The Dangerous Substances and Explosive Atmospheres Regulations 2002 may apply.

Chemical Engineering

From a chemistry perspective, the key function is the chemistry of the spent fuel pond water to minimise corrosion potential of the fuel cladding and thus ensure that the active soluble species are retained within the spent fuel. As ONR is a non-prescriptive regulator, there are no specific regulations associated with the control of chemistry for spent fuel pond water.

The licensee’s safety submission is assessed in line with the Chemistry Safety assessment principles and the Chemistry Assessment Technical Guidance (NSTAST-GD-89) . With specific regard to the assessment of spent fuel ponds, any assessment should also take conscience of the IAEA guide on storage of spent fuel, SSG-15 and if the spent fuel has been declared as waste, then the ONR, EA, SEPA and NRW joint guidance should also be considered.

As part of any submission all limits and conditions necessary in the interests of safety as defined under LC23 should be identified and those that are chemistry reliant will need to be explained in terms of how these limits and conditions are achieved and managed. This will subsequently be subject to appropriate proportionate inspection during operations.

Exemptions applied


PIT (Public Interest Test) if applicable