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STATUTORY INSTRUMENTS
2026 No. 839
HEALTH AND SAFETY
ENVIRONMENTAL PROTECTION
The Justification Decision (Generation of
Power by the RR SMR) Regulations 2026
Made - - - - 16th July 2026
Coming into force - - 17th July 2026
The Secretary of State makes these Regulations in exercise of the powers conferred by
regulation 4(1) of the Justification Decision Power (Amendment) (EU Exit) Regulations 2019
(“the 2019 Regulations”)(1) and in accordance with the requirements of regulation 14(1)
of the Justification of Practices Involving Ionising Radiation Regulations 2004 (“the 2004
Regulations”)(2).
The Secretary of State has consulted the persons required to be consulted under regulation 18
of the 2004 Regulations and such other persons as the Secretary of State considered it appropriate
to consult, and has taken such steps as the Secretary of State considered appropriate to bring the
proposed decision now contained in these Regulations to the attention of any person likely to be
affected by it.
In accordance with regulation 5(3) of the 2019 Regulations a draft of these Regulations was laid
before and approved by a resolution of each House of Parliament.
Citation, commencement and extent
1.—(1) These Regulations may be cited as the Justification Decision (Generation of Power by the
RR SMR) Regulations 2026 and come into force on the day after the day on which they are made.
(2) These Regulations extend to the United Kingdom.
Interpretation
2. In these Regulations—
“the RR SMR practice” means the class or type of practice which is the generation of power
from nuclear energy using uranium dioxide fuel of low enrichment in fissile content in a light
(1) S.I. 2019/215. Regulation 4(1) allows the Secretary of State to make, by regulations, a positive justification decision.
(2) S.I. 2004/1769, amended by S.I. 2018/430, S.I. 2019/24, and S.I. 2019/215. Justifying Authority for the purposes of this
instrument is defined in regulation 6 of S.I. 2004/1769.Document Generated: 2026-07-17
Status: This is the original version (as it was originally made). This
item of legislation is currently only available in its original format.
water cooled, light water moderated thermal reactor designed by Rolls-Royce SMR Limited
and where the specification of that reactor matches that set out in Annex 1 (pages 92 to
122) of the NIA Rolls-Royce SMR Application and Supplementary Information document
which was the subject of the consultation paper published by the Department for Environment,
Food and Rural Affairs on 6th October 2025 and titled “Consultation on the Nuclear Industry
Association’s Application for Regulatory Justification of the Rolls-Royce SMR designed by
Rolls-Royce SMR Limited(3)”.
Justification decision
3. For the purposes of regulation 14(1) of the Justification of Practices Involving Ionising
Radiation Regulations 2004 the following positive justification decision(4) has effect—
(a) the RR SMR practice is justified(5); and
(b) any class or type of practice which is—
(i)a development of the RR SMR practice; and
(ii)so similar to the RR SMR practice that the balance of benefits and detriments from
that class or type of practice does not materially differ from the balance of benefits
and detriments for the RR SMR practice,
is justified.
Emma Hardy
Parliamentary Under-Secretary of State
Department for Environment, Food and Rural
16th July 2026 Affairs
(3) The NIA Rolls-Royce SMR Application and Supplementary Information document and the consultation paper can be found
at: https://consult.defra.gov.uk/nuclear-justification/nuclear-rolls-royce-smr/. The page numbering (92 to 122) reflects the
PDF page numbering rather than the document numbering.
(4) Positive justification decision is defined in regulation 2 of S.I. 2019/215.
(5) Justified is defined in regulation 2 of S.I. 2019/215.
2Document Generated: 2026-07-17
Status: This is the original version (as it was originally made). This
item of legislation is currently only available in its original format.
EXPLANATORY NOTE
(This note is not part of the Regulations)
By these Regulations the Secretary of State makes a justification decision using the powers in
regulation 4 of the Justification Decision Power (Amendment) (EU Exit) Regulations 2019 (S.I.
2019/215) and in accordance with the Justification of Practices Involving Ionising Radiation
Regulations 2004 (S.I. 2004/1769) (“the 2004 Regulations”). The 2004 Regulations lay down basic
safety standards for the protection of the health of workers and the general public against the dangers
arising from ionising radiation.
The 2004 Regulations prohibit the carrying out of new classes or types of practice involving ionising
radiation unless justified. A class or type of practice is new where no practice within that class or
type of practice was carried out in the United Kingdom before 6th February 2018 and no justification
decision has been made that the class or type of practice is justified. Where the Secretary of State
has determined that a class or type of practice is new and is satisfied that the new class or type of
practice is justified because its individual or societal benefit outweighs the health detriment it may
cause, the Secretary of State is required to make a justification decision to that effect in the form of
regulations (see regulation 14(1) of the 2004 Regulations).
Regulation 2 of these Regulations defines the class or type of practice known as the RR SMR
practice. Regulation 3 is the positive justification decision.
A full regulatory impact assessment has not been produced for this instrument because there is no,
or no significant, impact on the private, voluntary or public sectors.
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