1 Personnel Protection System (PPS) – Definition Interlock system, to protect personnel from Ionising Radiation (and other hazards) –(Note: does not include equipment protection) Intended to satisfy the requirements of – –[UK] Ionising Radiation Regulations 1999 (IRR99) –IEC (?) “Functional Safety of Electrical / Electronic / Programmable- Electronic Safety-Related Systems” –>

2 Assisted search system, to clear personnel from (shielded) areas Door locks, to keep area clear of personnel Door switches, to make area safe on entry Warnings – audible and visual (– People!) Permit / Prevent operation of equipment, to control the hazard(s) –via “Permits to Operate” (PPS outputs) –> PPS – What it does

3 PPS Design Criteria (for Accelerators) Very low probability of ‘fail to danger’ Use ‘failsafe’ techniques – implies safety is achieved by switching things off –>

4 The Daresbury Laboratory Personnel Safety (PS) System (1 of 2) Used on: SRS, ESRF, Diamond, ERLP, ISIS (from 2007) Relay-based, modular, logic system ‘Dual Guardline’ System –duplicated inputs, logic, & outputs –both circuits must agree it’s safe to operate ( 2oo2 system) ‘Failsafe’ techniques –Current flow = safe –Relay logic (relays mostly fail open circuit) –Inputs from ‘Positive break’ safety switches –>

5 –Disable equipment by two independent means –Disable equipment in a failsafe manner –Disable via hardware, not software (but safety-PLC ok?) –> The Daresbury Laboratory Personnel Safety (PS) System (2 of 2) Provides audible and visible warnings (IRR99: ‘failsafe’?) –Search tone –Internal illuminating ‘Danger’ signs –Internal blue lighting –External illuminating signs Annual check to ensure that both guardlines are fully functional PS ‘Permits’ – principles for controlling equipment:

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11 MICE PPS Search Areas –MICE Decay Solenoid Area –MICE Hall

MICE Hall Decay Solenoid Area (shielding: schematical representation only) 4

13 MICE PPS – Controlled equipment ISIS Synchrotron Beam (to enable: Decay Solenoid Area vacated) –via ISIS PPS (hooks already included) MICE RF System (to enable: MICE Hall vacated) –switch off RF drive to IOTs –switch off HT to IOTs

14 Superconducting Magnets – sequence to enable 1) MICE Hall searched (but ‘Limited Access’ permitted) 2) Hall inspection for loose magnetic material – not PS function 3) Insert and turn ‘Magnet Enable’ key Dropping search does not disable magnet PSU, – turn off key does –Interface to magnet PSU t.b.d. Other systems … ? (over to you) MICE PPS – Controlled equipment, contd.