BA6 Cooling Towers Test Day Process Control Functionality and Performance Tests TCR – PCR Monitoring

Objectives Test the process functionality and performance Better understand impact of the new cooling system on SPS operation (ST-CV, TCR, PCR) Validate the TCR monitoring in a real fault situation Validate the new joint TCR-PCR monitoring GTPM (Gestion Technique Panne Majeure)

SAFETY MODE TEST The main objective of the « safety mode » functionality is to keep the temperature of the primary cooling water (raw water) within the upper critical limit in order to preserve the SPS accelerator from being stopped by a increase of the temperature of the secondary circuit (demineralised circuit) The safety mode is automatically triggered when under specific conditions the temperature of the primary water increases and reaches about 26.5 Cooling tower considered out of order is replaced by the safety regulation circuit. The hot water is therefore rejected to the Nant d’Avril. Information is transmitted to the SIG control system which automatically supplies with cold water the SPS Primary circuit to balance the wasted missing water The cold water flow rate represents the exact quantity of the wasted hot water.

SAFETY MODE TEST 9: 30 am Cooling towers are placed in normal operating conditions The SPS main magnets have been pulsed since 6: 00 am at 400GeV and all the power equipment has been switched on. The conditions corresponded to the normal SPS physics operation. Fans & regulation system are working properly Parameters at this moment T ext = 10 º C T retour = 30.5 º C T depart = 21 º C Flow rate = 564 l/s (through towers 2 and 3) 10:00 am Tdepart and flow rate increased T retour = 31.8º C T depart = 23.3º C flow rate = 638 l/s (through towers 2, 3 and 4)

SAFETY MODE TEST 9:30 am Fans are put out of order (simulation of regulation problem) T depart increased  º C T retour  31 º C Flow rate  500 l/s 10:00 am Safety mode triggered (Wasted water flow rate regulation on ) Flow rate regulation system with SIG is working properly Parameters at this moment Safety flow rate  230 l/s Wasted flow rate  227 l/s SIG cold waste flow rate  225 l/s The BA4 regulation tank showed to perfectly absorb the flow rate disturbances. Regulation keeps the level between 2.3 and 2.7 m.

SAFETY MODE TEST Status after having been triggered 10:20 am Tdepart & towers input flow rate decreasing T depart increased  25.5 º C T retour  31 º C 10:40 am Stabilization Tdepart goes on decreasing slowly up to recovering the 21º C of origin. The safety mode can compensate a disturbance or saturation in the heating exchange in the cooling towers. The test is concluded to be positive

SAFETY MODE TEST Determination of the BAs critical point 10:40 am Safety mode is manually turned off Some parameters at this moment: T depart increased  21.5 º C T retour  31.5 º C 10:50 amNo fans; no safety mode. Tdepart starts to increase. T depart increased  26.7º C —> 28.4 º C T retour  32.8 º C Maximum reached The BA3 has stopped by 11:09 (TCR confirmed during the afternoon debriefing meeting that it had been at 11:06) The test showed that the BA’s can work with a Tdepart up to around 28 º C SL indicated: the stop has been due to a temperature interlock on the sextupoles in BA6 that were not correctly connected to the demineralised water circuits. Consequently the BA3 could have been in operation some more time

BA4 Regulation tank Upon a too high level at the BA4 regulation tank ( 4.3 m ) stopped the SIG station stopped progressively as it was expected As a consequence of the stop of the SIG station, BA1 and BA3 stopped ( reason not determined during the tests ). In the afternoon debriefing meeting R. Mollay indicated that a too low primary water pressure during 30s causes the BAs to stop ) No alarm appeared in TCR concerning the stop of the cooling stations at BA1 and BA3. TCR operators detect the stop because the electrical alarms coming from the compensators. Alarms for the pressure of the primary circuit are being implemented for all the BA’s. Remote reset and restart of BA1 and BA3 not possible, on-site intervention necessary – modification in the PLC demi water under investigation. TCR measurement of the regulation tank level identified as wrong – is being corrected.

TCR-PCR Monitoring Globally the TCR monitoring worked as foreseen Some minor errors have been identified and are corrected All information for TCR operation available The GTPM monitoring worked correctly –Easy detection of machine state –Easy detection of the state of the technical infrastructure –Easy communication between TCR and PCR TCR process and monitoring documentation will be completed with the experience gained during the tests

Conclusion Satisfying functioning of the cooling The SPS can continue working in physics mode for approximately 3 hours with the cooling towers in the safety mode – total transparency Good experience as to what happens in case of a fault Better understanding of the cooling monitoring