NPDgamma Liquid Hydrogen Target Safety Review Warning Alarms and Interlocks At LANL November 29-30, 2005

A Plan is to have three-tiered hierarchy of status indicators for the system: Normal: The system operating as designed with all interlocks and sensors active and within set ranges. Warning: - Some sensor(s) are at values between low and high trip points. Local indication (target computer gives warning). - Target operator attention is required but automatic shutdown action is not needed. Alarm: - Some sensor(s) have exceeded their high trip levels. - Automatic safety and/or shutdown systems take over. - Local indications; horn and flashing light on FP12, area alarm at ER2/ER1, CCR has alarm and CCR gives alarm announcement at Lujan - All personnel should leave ER1/ER2.

SensorLocationTrip pointAction H 2 concentration #1 H 2 concentration #2 Shed or FP12 cave, in stagnant air near ceiling GHS tent or enclosure 10% of LELWarning H 2 concentration #1 H 2 concentration #2 Shed or FP12 cave, in stagnant air near ceiling GHS tent or enclosure 25% of LELAlarm. H 2 system shutdown and H 2 dump. Electrical power to cave shut off. Vacuum pressure sensorVacuum vesselHigher than set pointWarning RGAVacuum vesselHe peak > Low set pointWarning RGAVacuum vesselHe peak > High set pointAlarm. H 2 system shutdown and H 2 dump. RGAVacuum vesselN 2 peak > Low set pointWarning RGAVacuum vesselH 2 O peak > Low set pointWarning He source pressure for channels Helium channelsp < 3 psigWarning He flow out from channels Helium channelsFlow < set pointWarning H 2 pressureTarget H 2 gas in exhaust line p > 16 psig, p < 9 psigWarning O 2 concentrationShed or at FP12 cave, at normal breathing space elevation LowWarning