MINISTRY OF DEFENCE FLOOR 5, ZONE B, MAIN BUELDING WHITEHALL LONDON SW1A 2H8 Ministry of Defence STUART ANDREW MP PARLIAMENTARY OF STATE AND MINISTER FOR DEFENCE PROCUREMENT Tetephone 020 7218 9000 (Switchboard) November 2018 In my response (Official Record 15 May 2018) confirmed that I would write to you with a substantive response to your questions: ?To ask the Secretary of State for Defence, how many nuclear safety events have occurred on submarines clocked at Faslane- in each year since 2006 by class of submarine and type of incident. To ask the Secretary of State for Defence, how many leaks of radioactive coolant there have been from submarines berthed at Faslane in each of the last ten years.? It may be helpful if I provide some context to the way in which events are categorised and reported. Her Majesty?s Naval Base (HMNB) Clyde, in common with other defence and civil nuclear sites, employs an agreed system for raising Nuclear Site Event Reports (NSERs), which detail their investigation and categorisation according to their safety significance. These events may be near-misses, equipment failures, human error or procedural failings. They are raised, however minor they may appear, to encourage a comprehensive, robust reporting culture, undertake learning from experience and to take early corrective action. This reporting process has been agreed by the Defence Nuclear Safety Regulator (DNSR) and is subject to routine inspections. In November 2015, the NSER categorisation criteria were updated and an additional ?Below Scale? category was introduced to align better with wider industry best practice as recognised by DNSR and the Office for Nuclear Regulation (ONR). Following joint inspection of HMNB Clyde?s arrangements in May 2016, DNSR graded their assessment as Green (Adequate), the higher assessment. The relevant criteria for before and after 2015 are at Annex A. Deidre Brock MP House of Commons London SW1A 0AA On this basis, from the records available, the following NSERs were raised for submarines berthed or docked at Faslane for each calendar year since 2006: 21:5?? Site Events - Category A Category Category Category Swiftsure Class SSN 0 1 2 8 Trafalgar Class SSN 0 0 0 .1 Vanguard Class SSBN 1 6 2 3 Total 24 in 2006 24:39? Site Events Category A Category Category Category Swiftsure Class SSN 1 1 2 15 Trafalgar Class SSN 0 1 8 4 Vanguard Class SSBN 0 1 4 6 Total NSERs 43 in 2007 ?$rggear Site Events Category A Category 8 Category Category Swiftsure Class SSN 0 2 2 5 Trafalgar Class SSN 0 1 1 1 Vanguard Class SSBN 4 11 14 Total NSERs 41 in 2008 25338? Site Events I Category A Category Category Category Swiftsure Class SSN 0 0 4 8 Trafalgar Class SSN 0 0 0 1* Vanguard Class SSBN 0 0 8 10 Total 31 in 2009. Reported through Commodore Devonport Flotilla during visit to Clyde. garicgear S'te Events Category A Category 8 Category Category Swittsure Class SSN 0 0 0 0 Astute Class SSN 0 4 7 Trafalgar Class SSN 0 0 3 Vanguard Class SSBN 0 2 6 10 Total 32 in 2010 HMS ASTUTE first arrived at Faslane in November 2009. S'te Events - Category A Category Category Category Astute Class SSN 0 0 3 0 Trafalgar Class SSN 0 0 0 1 Vanguard Class SSBN 0 0 10 10 Total NSERS 24 in 2011 Nuclear Site Events - 2012 Category A Category Category Category Astute Class SSN 0 0 2 6 Trafalgar CEass SSN 0 0 1 Vanguard Class SSBN 1 7 4 Total NSERS - 21 in 2012 ?31049? Site Events Category A Category Category Category Astute Class SSN 0 2 9 Trafalgar Class SSN 2 2 Vanguard Class SSBN 6 11 Total NSERS 32 in 2013 2551116? Site Events Category A Category Category Category Astute Class SSN 5 6 Trafalgar Class SSN 0 0 2 4 Vanguard Class SSBN 0 0 14 8 Total 39 in 2014 Nuclear Site Events Below 2015 Category A Category Category Category Scale* Astute Class SSN 0 0 3 7 4 Trafalgar Class SSN 0 16 10 0 Vanguard Class SSBN 13 t1 1 Total NSERS 65 in 2015 Updated categorisation criteria from November 2015 gage? 3? Events Category A Category Category Category Below Scale Astute Class SSN 0 1 2 9 18 Trafalgar Class SSN 0 0 0 1 10 Vanguard Class SSBN 0 0 5 12 22 Total NSERS 80in 2016 2:1c7lear 3? Events Category A Category Category Category Below Scaie Astute Class SSN 0 0 1 5 26 Trafalgar Class SSN 0 0 0 0 4 Vanguard Class SSBN 0 0 1 25 10 Total NSERs 73 in 2017 You will notice that there are two Category A events listed from 2006 and 2007. Given that the safety significance of all reported events has remained very low, it is worth highlighting that in neither event was any radiological contamination evident. The details are: . 2006 Flexible pipework failure during routine maintenance led to a contained submarine compartment water spill, with no loss of water into the environment. A member of staff became wet: as a precaution, the individual was monitored to ensure no contamination, and was given the all clear. a 2007 - During a pressure test of pipework connected to a submarine, an incorrect valve position resulted in a discharge of water. 150 litres were discharged and no detectable radioactive contamination was discovered. None of the events caused harm to the health of any member of staff on the Naval Base, or to any member of the public, and the safety significance has remained very low. The Ministry of Defence, however, takes all such incidents, no matter how minor, extremely seriously and ensures they are investigated and appropriate measures put in place to prevent a recurrence. With regards to your second question related to leaks of radioactive coolant, i can confirm that there have been no such leaks of primary coolant to the environment from any submarines berthed at Faslane in the last ten years. I hope that this response is helpful. A copy of this letter will be placed in the Library of the House. STUART ANDREW MP An nex A To the response to Parliamentary Questions Reference 142889 142890 CATEGORISATION OF NUCLEAR AND RADIOLOGICAL EVENTS (TO NOV 15) Cat Nuclear Event Consequence Description Actual or high potential for radioactive release to the environment or over exposure to radiation. Actual or high potential for 3 contained release within building or submarine or unplanned exposure to radiation. Major failure of Site or Nuclear Propulsion Nuclear Weapon services. Major reduction of defence in depth. Major failure in administrative controls or regulatory compliance. Moderate potential for future release or exposure, or localised release within a designated radiological controlled area. Minor failure of Site or services (eg with protection via defence in depth). Minor regulatory or procedural compliance breach. Low potential for release - but may contribute towards an adverse trend producing latent conditions. Poor safety culture, eg: Failure to report shortfalls. - Communication failures. - Leadership issues. CATEGORISATION OF NUCLEAR AND RADIOLOGICAL EVENTS (POST NOV 15) Cat Release of radioactive Radiological Safe operation or safe material consequence condition Actual or high potential for radioactive release to the Unplanned individual A environment of quantities in exposure to radiation excess of IRRQQ notification >200u8v. limits. Actual or high potential for a contained release within or submarine. Unplanned individual Could significantly prejudice Actual or high potential for exposure to radiation the requrrimentrs] o; a safety radioactive release to the >20uSv. 22:: a; ?re?ght: sa environment of quantities below IRR 99 notification limits. Moderate potential for future release to the environment. Localised release within a designated radiological Unplanned individual Failure of a line of defence controlled area. exposure to radiation or protection or a similar <20uSv. occurrence Actual radioactive release to the environment where quantity of release is likely to be Below Detection Threshold (BDT). Low potential for release but may contribute towards May affect the safe an adverse trend producing operation or safe condition latent conditions. Of safety interest or concern, including: Below (1) human error; Scale (2) equment or process failures that cause near misses; (3) abnormal occurrences.