Office for Nuclear Regulation

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System based inspection at the Devonport Licensed site

Executive summary

Purpose of Intervention

The purpose of the intervention was to conduct a system based inspection at the Devonport Licensed site (operated by Devonport Royal Dockyard Limited (DRDL)) in accordance with the strategy defined by ONR's Operational Facilities Programme for 2017/18.

This intervention was undertaken by an ONR's civil, mechanical and site inspectors for the Devonport Licensed site.

Interventions Carried Out by ONR

For this intervention, ONR performed a System Based Inspection (SBI) of the Submarine Refit Complex (SRC) structures and boundaries to judge their performance against their safety functional requirements. Structures and boundaries include: dock structures; dock buildings; dock caissons; central promontory structures; and dock cradles. Through sampled examination of the arrangements made for SRC structures and boundaries ONR inspectors performed compliance inspections against the following Licence Conditions where applicable:

Explanation of Judgement if Safety System Not Judged to be Adequate

From the inspection, ONR inspectors judged that, overall, the SRC structures and boundaries met the requirements of the safety case, and are therefore adequate.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

Based on the specific areas sampled during the course of the system inspection, ONR found that DRDL has adequate arrangements in place to ensure that the SRC structures and boundaries are operated and maintained in accordance with the appropriate safety cases. Ratings for each of the Licence Conditions are as follows:

LC10 (training) - IIS Rating GREEN. The inspection team sampled the training material and training records of operational staff and found them to be of an adequate standard.

LC23 (Operating rules) - IIS Rating GREEN. The inspection team were satisfied that the SRC safety case limits were identified through an adequate set of operating rules and that these were appropriately implemented.

LC24 (Operating instructions) - IIS Rating GREEN. In the areas sampled, the inspection team found adequate operating instructions in place to support the operation and maintenance of the SRC structures and boundaries. These were being implemented appropriately.

LC27 (Safety mechanisms, devices and circuits) - The Licensee informed ONR that there were no known recognised Safety Mechanisms, Devices and Circuits (SMDC's) associated with this system based inspection. As such LC27 was considered to be not applicable for this SBI.

LC28 (Examination, inspection, maintenance and testing) - IIS Rating GREEN. The inspection team sampled maintenance arrangements from the safety case through to the on plant job plans and found them to be adequate.

LC34 (Leakage and escape of radioactive material and radioactive waste) - The Licensee informed ONR that there were no known recognised structures or boundaries that related to leakage and escape of radioactive material and radioactive. As such LC 34 was considered to be not applicable for this SBI.

The intervention was performed in line with ONR’s guidance requirements (as described in our technical inspection guides) in the areas inspected.

Conclusion of Intervention

A hot debrief was provided by the ONR inspectors to the relevant DRDL staff where the following points were raised:

There was a lack of clarity regarding the latest version of documentation / safety case within the DRDL electronic database and in the definition and justification behind the use of some plant operating procedures.

Delay in certain asset remedial measures was noted. This is causing a backlog of maintenance issues. Whilst these may not be of direct nuclear significance they do not represent good practice.

Examples of good practice were noted within the implementation of the identified operating instructions (IOI) with respect to the vehicle impact barrier (VIB).

After considering the evidence sampled against Licence Conditions 10, 23, 24 and 28, ONR judge that the SRC structures and boundaries meet the requirements of the safety case and are therefore this SBI records a GREEN rating for these Licence Conditions

No SMDC's (Safety Mechanisms Devices and Circuits) were highlighted by the licensee as being relevant to this inspection and thus this Licence Condition 27 was considered not applicable for this SBI.

No civil structural aspects were considered relevant by the licensee to Licence Condition 34 requirements and thus this Licence Condition was considered to be not applicable for this SBI.