1. Status 100% 30% 100% STATUS REPORT on Electromagnetical Perturbations on the Hardwired Safety Alarms  The investigations to understand the causes of hardwired alarm level 3 induced by electromagnetic perturbations in correspondence of the 18kV power breakdown indicated two actions: A Implementation of a low-pass filter on the input of the hardware-triggering unit, A Revision of the shielding and grounding of the existing hardwired network. A Implementation of a data logger on the main hardwired links.

2. Status OK OK OK OK STATUS REPORT on Electromagnetical Perturbations on the Hardwired Safety Alarms  Implementation of a low-pass filter on the input of the hardware-triggering unit A Designed using MATLAB and test field measurements A Installed, tested and in operation since May 2001 A NO spurious alarms due to Electromagnetical Perturbations have been recorded A Inspected by TIS and their EMC consultant

3. Triggering unit’s equivalent circuit: with and without the input filter.

4. Comparison between the experimental data and the simulations

5. Note that the input voltage of the triggering units follows closely the perturbation in case A Note that the presence of the input filter avoids that short-lived events trigger alarm while long- lived events trigger alarm

6. Status OK OK Planned Planned STATUS REPORT on Electromagnetical Perturbations on the Hardwired Safety Alarms  Revision of the shielding and grounding of the existing hardwired network. A Review of the existing cable paths and rack location A First TIS and EMC consultant audit A Recommendations by TIS expected middle October 2001 A Work on the cable connections, terminations and shielding start middle October 2001

7. Status OK STATUS REPORT on Electromagnetical Perturbations on the Hardwired Safety Alarms  Implementation of a data logger on the main hardwired links. A Design, installation and testing of a LabVIEW data logger

8. Photos of the Installation Filters Data Logging HW Alarm Terminal blocks