Office for Nuclear Regulation

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LC35 inspection of PFR and DFR and LC2 inspection of site perimeter

Executive summary

Purpose of intervention

The purpose of the intervention was to complete a review of licensees arrangements for the decommissioning of Dounreay Fast Reactor (DFR) and Prototype Fast Reactor (PFR) as required by Licence Condition (LC) 35, and to complete an LC2 inspection of the marking of the site boundary arrangements.

Interventions carried out by ONR

I outlined ONR's initial response to the licensees level 3 investigation into issues identified by ONR in relation to compliance with LC23 (Operating Rules) and LC24 (Operating Instructions).

I carried out an LC35 (Decommissioning) inspection of both PFR and DFR, and completed an LC 2 inspection of the DSRL site boundary. In addition I was given an overview of the DFR breeder removal project and of the intended changes to the control of decommissioning work control specifically at PFR and DFR over the next 12 months.

Explanation of judgement if safety system not judged to be adequate.

Not applicable.

Key findings, Inspectors opinions and reasons for judgements made

I judge that at PFR and DFR there exists adequate arrangements for the decommissioning of both facilities, and that the ongoing review of each of the Lifetime Plans (LTP) appears to be well managed with the objective of ensuring the facility LTPs are both comprehensive in hazard removal and resourced.

The site arrangements for LC2 (Marking of the site boundary) are judged adequate, noting that on the seaward side of the site the actual marked boundaries are some distance from the actual fence, and in some instances are underwater at high water as a result of coastal erosion. The site agreed an action to ensure that three signs were repositioned to ensure they are visible. All of the required signage associated with the boundary fence was observed to be adequate.

DSRL stated that they believe the recent LC23/24 non compliance represented a paper exercise as opposed to an issue relating to nuclear safety, and that they had classified it accordingly as INES0. I informed the licensee that ONR has consulted the national INES officer and considers that the event is of greater significance and has reported as INES1 as part of the quarterly reporting arrangements to ministers.

Conclusion of intervention

I conclude that ongoing review of the LTP at DFR and PFR is being managed adequately, and that overall decommissioning of both reactors is making reasonable progress.

The site boundary fence is in good condition and is appropriate signed. The actual site boundary is generally marked to an adequate level although there are instances of this boundary now being underwater at high water. One action was agreed to make three boundary markers more visible.

The site declaration that the recent LC23 / 24 event represented a paper exercise only is disappointing as it does not reflect ONR opinion nor is it commensurate with the observed deficiencies against the legal requirements of LC23 and 24.


ONR intends to complete further inspection of compliance with arrangements made under LC22, 23 & 24 across the DSRL site in November 2013. ONR will subsequently review the findings of this sampling exercise and will determine if any further regulatory action is warranted.

Updated 2014-03-11