Permissioning inspection - Technical assessment guides

ONR has established its Safety Assessment Principles (SAPs) which apply to the assessment by ONR specialist inspectors of safety cases for nuclear facilities that may be operated by potential licensees, existing licensees, or other duty-holders. The Security Assessment Principles (SyAPs) apply to the assessment of security plans which include site security plans and transport security statements. The principles presented in the SAPs and SyAPs are supported by a suite of guides to further assist ONR's inspectors in their technical assessment work in support of making regulatory judgements and decisions.

This page contains Technical Assessment Guides (TAGs). These primarily provide guidance to ONR inspectors on the interpretation and application of the SAPs and SyAPs. However, some also contain guidance relevant to principles underlining the enforcement of licence condition compliance, which supplements the Technical Inspection Guides. Thus the TAGs have relevance to all inspectors within ONR, regardless of function. The TAGs also provide information to licensees and dutyholders regarding ONR's expectations of the nature and content of relevant technical elements of safety cases and security plans.

The TAGs provide guidance in particular technical areas, and they are to be used at the discretion of inspectors.

Responsibility for the maintenance of TAGs is shared between ONR's Professional Leads for individual technical areas and the Regulatory and Technical Standards sub programme within ONR's Technical Division.

The guides available below are the latest issues. As revised versions are produced they will replace the older versions.

Official sensitive

Those civil nuclear industry dutyholders who need a document containing sensitive nuclear information, should contact cns.support@onr.gov.uk

Document ID	Review date	Title
Nuclear safety
NS-TAST-GD-002 (Rev 8)	July 2023	Radiation Shielding
NS-TAST-GD-003 (Rev 9)	October 2022	Safety Systems
NS-TAST-GD-004 (Rev 7)	April 2023	Fundamental Principles
NS-TAST-GD-005 (Rev 11)	March 2023	Guidance on the Demonstration of ALARP (As Low As Reasonably Practicable)
NS-TAST-GD-006 (Rev 5)	October 2025	Design Basis Analysis
NS-TAST-GD-007 (Rev 4)	September 2020	Severe Accident Analysis
NS-TAST-GD-009 (Rev 6)	October 2023	Examination, Inspection, Maintenance and Testing of Items Important to Safety
NS-TAST-GD-010 (Rev 6)	September 2021	Early initiation of safety systems
NS-TAST-GD-011 (Rev 2)	Withdrawn pending review	The single failure criterion
NS-TAST-GD-013 (Rev 8)	October 2023	External hazards
NS-TAST-GD-014 (Rev 6)	November 2024	Internal Hazards
NS-TAST-GD-015 (Rev 3)	May 2025	Electromagnetic Interference
NS-TAST-GD-016 (Rev 7)	April 2025	Integrity of Metal Structures, Systems and Components
NS-TAST-GD-017 (Rev 4)	November 2025	Civil Engineering
NS-TAST-GD-018 (Rev 8)	October 2023	Criticality Warning Systems
NS-TAST-GD-019 (Rev 5)	April 2024	Essential Services
NS-TAST-GD-020 (Rev 6)	May 2025	Civil Engineering Containments for Reactor Plants
NS-TAST-GD-021 (Rev 6)	June 2024	Containment: Chemical Plants
NS-TAST-GD-022 (Rev 7)	December 2024	Ventilation
NS-TAST-GD-023 (Rev 6)	August 2024	Control of Processes Involving Nuclear Matter (SAP - ENM. 1 to 8)
NS-TAST-GD-024 (Rev 7)	June 2023	Management of Radioactive Material and Radioactive Waste on Nuclear Licensed Sites
NS-TAST-GD-026 (Rev 5)	September 2022	Decommissioning
NS-TAST-GD-027 (Rev 6)	December 2021	Training and assuring personnel competence
NS-TAST-GD-028 (Rev 6)	October 2024	Control and Instrumentation Aspects of Nuclear Plant Commissioning
NS-TAST-GD-029 (Rev 5)	November 2023	Graphite reactor cores
NS-TAST-GD-030 (Rev 7)	April 2024	Probabilistic Safety Analysis
NS-TAST-GD-031 (Rev 6)	April 2023	Safety related Systems and Instrumentation
NS-TAST-GD-033 (Rev 7)	February 2024	Duty Holder Management of Records
NS-TAST-GD-035 (Rev 6)	December 2022	The Limits and Conditions for Nuclear Safety (Operating Rules)
NS-TAST-GD-036 (Rev 5)	February 2021	Diversity, redundancy, segregation and layout of mechanical plant
NS-TAST-GD-038 (Rev 9)	November 2022	Radiological Protection
NS-TAST-GD-041 (Rev 7)	January 2024	Criticality Safety
NS-TAST-GD-042 (Rev 5)	September 2023	Validation of Computer Codes and Calculation Methods
NS-TAST-GD-043 (Rev 6)	July 2024	Radiological Analysis - Normal Operation
NS-TAST-GD-045 (Rev 6)	April 2024	Radiological analysis - Fault conditions
NS-TAST-GD-046 (Rev 6)	October 2023	Computer Based Safety Systems
NS-TAST-GD-048 (Rev 6)	July 2023	Organisational Change
NS-TAST-GD-049 (Rev 7)	November 2023	Licensee Core Safety and Intelligent Customer Capabilities
NS-TAST-GD-050 (Rev 8)	October 2025	Periodic Safety Reviews (PSRs) [NS-TAST-GD-050]
NS-TAST-GD-051 (Rev 7)	December 2024	The purpose, scope and content of safety cases
NS-TAST-GD-056 (Rev 7)	February 2023	Nuclear Lifting Operations
NS-TAST-GD-057 (Rev 6)	October 2022	Design Safety Assurance
NS-TAST-GD-058 (Rev 4)	March 2023	Human Factors Integration
NS-TAST-GD-059 (Rev 5)	December 2022	Human Machine Interface
NS-TAST-GD-060 (Rev 4)	March 2022	Procedure Design and Administrative Controls
NS-TAST-GD-061 (Rev 4)	March 2022	Staffing levels and task organisation
NS-TAST-GD-062 (Rev 4)	October 2025	Workplaces and Work Environment
NS-TAST-GD-063 (Rev 5)	July 2022	Human Reliability Analysis
NS-TAST-GD-064 (Rev 4)	December 2021	Allocation of Function between Human and Engineered Systems
NS-TAST-GD-065 (Rev 4)	January 2023	Function and Content of the Nuclear Baseline
NS-TAST-GD-067 (Rev 2)	February 2022	Pressure Systems
NS-TAST-GD-072 (Rev 4)	July 2022	Function and Content of a Safety Management Prospectus
NS-TAST-GD-075 (Rev 3)	September 2025	Safety of Nuclear Fuel in Power Reactors
NS-TAST-GD-077 (Rev 6)	July 2024	Supply Chain Management Arrangements for the Procurement of Nuclear Safety Related Items or Services
NS-TAST-GD-079 (Rev 6)	April 2024	Licensee Design Authority Capability
NS-TAST-GD-080 (Rev 4)	January 2023	Challenge Culture, Independent Challenge Capability (including an Internal Regulation function) and the Provision of Nuclear Safety Advice
NS-TAST-GD-081 (Rev 4)	June 2024	Safety Aspects Specific to Storage of Spent Nuclear Fuel
NS-TAST-GD-083 (Rev 2)	November 2023	Land Quality Management
NS-TAST-GD-087 (Rev 2)	June 2022	Control of Property Transactions on Licensed Sites
NS-TAST-GD-088 (Rev 3)	January 2024	Chemistry of Operating Civil Nuclear Reactors
NS-TAST-GD-089 (Rev 1)	February 2026	Chemistry Assessment
NS-TAST-GD-093 (Rev 2)	Withdrawn pending review	Guidance for undertaking Leadership and Management for Safety Reviews
NS-TAST-GD-094 (Rev 2)	July 2024	Categorisation of Safety Functions and Classification of Structures and Components
NS-TAST-GD-096 (Rev 0)	April 2023	Guidance on Mechanics of Assessment
NS-TAST-GD-097 (Rev 2)	April 2025	Criticality Safety Assessment of Transport Packages
NS-TAST-GD-098 (Rev 2)	October 2024	Asset Management
NS-TAST-GD-099 (Rev 1)	June 2021	Transport Engineering Assessment
NS-TAST-GD-100 (Rev 2)	October 2024	Shielding and Dose Rate Safety Assessment of Transport Packages
NS-TAST-GD-101 (Rev 1)	January 2023	Geological Disposal
NS-TAST-GD-102 (Rev 1)	June 2023	General Guidance for Mechanical Engineering Specialism Group
NS-TAST-GD-103  (Rev 1)	October 2023	Emergency Power Generation
Civil Nuclear Security
CNS-TAST-GD-1.1 (Rev 1)	March 2025	Security Governance and Leadership
CNS-TAST-GD-1.2 (Rev 2)	March 2022	Organisational Security Capability
CNS-TAST-GD-1.3 (Rev 1)	March 2025	Security Decision Making
CNS-TAST-GD-1.4 (Rev 1)	March 2025	Organisational Learning for Security
CNS-TAST-GD-1.5 (Rev 1)	March 2024	Security Assurance Processes
CNS-TAST-GD-2.1 (Rev 1)	March 2023	Maintenance of a Robust Security Culture
CNS-TAST-GD-3.1 (Rev 2)	March 2022	Analysis of Security Roles & Associated Competencies
CNS-TAST-GD-3.2 (Rev 2)	March 2022	Identification of Learning Objectives and Training Needs
CNS-TAST-GD-3.3 (Rev 2)	March 2022	Measurement of Competence
CNS-TAST-GD-3.4 (Rev 2)	March 2022	Organisation of and Support to the Training Function
CNS-TAST-GD-4.1 (Rev 1)	March 2024	Procurement and Intelligent Customer Capability
CNS-TAST-GD-4.2 (Rev 1)	March 2024	Supplier Capability
CNS-TAST-GD-4.3 (Rev 1)	March 2024	Oversight of Suppliers
CNS-TAST-GD-4.4 (Rev 1)	March 2024	Commissioning
CNS-TAST-GD-5.1 (Rev 1)	March 2023	Reliability and Resilience
CNS-TAST-GD-5.2 (Rev 1)	March 2023	Examination, Inspection, Maintenance and Testing
CNS-TAST-GD-5.3 (Rev 1)	March 2022	Sustainability
CNS-TAST-GD-6.1 (Rev 1)	April 2023	Categorisation for Theft
CNS-TAST-GD-6.2 (Rev 1)	March 2022	Categorisation for Sabotage
NS-TAST-GD-6.4 (Rev 1)	March 2022	Vulnerability Assessment
CNS-TAST-GD-6.5 (Rev 1)	March 2022	Adjacent or Enclave Nuclear Premises
CNS-TAST-GD-6.6 (Rev 1)	March 2024	Nuclear Construction Sites
CNS-TAST-GD-6.7 (Rev 1)	May 2023	Class A Carriers – Transport Security Statements and Plans
CNS-TAST-GD-7.1 (Rev 1)	March 2023	Effective Cyber and Information Risk Management
CNS-TAST-GD-7.2 (Rev 1)	March 2023	Information Security
CNS-TAST-GD-7.3 (Rev 1)	March 2022	Protection of Nuclear Technology and Operations
CNS-TAST-GD-7.4 (Rev 1)	March 2022	Physical Protection of Information
CNSS-TAST-GD-7.5 (Rev 3)	March 2024	Preparation for and Response to Cyber Security Events
CNS-TAST-GD-8.1 (Rev 1)	November 2024	Cooperation of Departments with responsibility for delivering vetting and ongoing personnel security arrangements
CNS-TAST-GD-8.2 (Rev 1)	November 2024	Pre-employment Screening and National Security Vetting
CNS-TAST-GD-8.3 (Rev 1)	November 2024	Ongoing Personnel Security Aftercare
CNS-TAST-GD-9.1 (Rev 1)	March 2024	CNC Response Force
CNS-TAST-GD-9.2 (Rev 1)	March 2024	Local Police Forces
CNS-TAST-GD-9.3 (Rev 1)	March 2024	Security Guard Services
CNS-TAST-GD-10.1 (Rev 2)	October 2024	CT Measures EP&R Planning
CNS-TAST-GD-10.2 (Rev 2)	October 2024	Testing and Exercising the Security Response
CNS-TAST-GD-10.3 (Rev 2)	October 2021	Clarity of C3 Arrangements for Nuclear Security Events
CNS-TAST-GD-11.1 (Issue 1.1)	May 2021	Guidance on the Security Assessment of Generic New Nuclear Reactor Designs
Safeguards
SG-TAST-GD-001 (Rev 3)	January 2023	Safeguards technical assessment guidance
SG-TAST-GD-002 (Rev 1)	January 2022	Nuclear Material Accountancy