Hardware and Software Upgrade for the Solution Measurement and Monitor System at Rokkasho Reprocessing

Transcription

1 Hardware and Software Upgrade for the Solution Measurement and Monitor System at Rokkasho Reprocessing R. Plenteda a, A. Alessandrello a, M. Frankl a, W. Deringer a, M. Lang a, M. Cronholm a, K. Baird a, D. Breban a, C. Creusot a a International Atomic Energy Agency, Vienna, Austria Abstract. Rokkasho Reprocessing Plant is the largest reprocessing facility under IAEA Safeguards. Part of the numerous unattended measurement and monitoring systems (more than 20 NDA systems), one of the most important and complex is the Solution Measurement and Monitoring System (SMMS). SMMS is applied to the chemical liquid processing part of the plant operation, and involves over 90 vessels or extractors. The installed measurement instruments consist mainly of manometers and temperature sensors. The pressure readings from the manometers are used to calculate the density and the mass of the solution in each monitored tank. For the 12 most strategic tanks, IAEA owned manometers are directly connected to the Operator s dip tubes with associated data collection system (SMMS-I type instruments) aiming at collecting and sending data to a common database. For the remaining tanks/equipment the operator s instruments are used (SMMS-II). The data coming from both SMMS types are pre-processed and reviewed by the Solution Monitoring Software (SMS). The software basically provides calculation of volumes, densities, flow rates in major process vessels, and includes as well advanced automatic features to support the inspectorate in the verification activities. This paper describes the upgrade of the SMMS-I acquisition hardware and the SMMS Operating Software (SOS) at the IAEA local cabinets, for a much more robust and reliable overall system through different levels of redundancy and new features. The software also allows the in-situ calibration of manometers using an ad-hoc portable calibration system. 1. SMMS-1 System description The SMMS-1 system is intended for an unattended measurement of mass of Pu containing solutions in key process tanks under Safeguards. The manometers are used to measure the pressure of at least two different depths in each tank. SMMS-1 monitors 12 different tanks and is installed in 10 cabinets. The cabinets have been converted to the MENSOR CPG 2500-S based system (replacing the old RUSKA manometers based design). Two redundant CPG 2500-S (see Fig. 1) are mounted in a removable cage which is then pneumatically connected with flexible pipes in the cabinet.

2 Figure 1: MENSOR CPG 2500 and CPG 2500-S unit Depending on the system there can be one, two or three cages in a cabinet. The SMMS-1 cage is shown in Fig. 2 Figure 2: SMMS-1 Cage The System calibration can be performed in the field using a calibration box and the calibration port on the front side of the cage (Fig. 3)

3 Figure 3: SMMS-1 Cage Connectors, Front View (Left) and Back View (Right) Figure 4: SMMS-1 Full cabinet with one cage 2. Redundancy concept The design includes three (3) levels of redundancy: 1. Each tank is served by 2 double channel manometers to have pneumatic redundancy. 2. Two cabinets are directly connected together in twin mode via Ethernet (Cat 5) cable; each cabinet has an industrial computer that interrogates a local manometer (line A) and the twin cabinet manometer (line B). 3. The manometer reading can be done also in attended mode from the manometer display in case of network failure or failure of both computers. Figure 5 shows the SMMS-1 twin

4 mode configuration. Notice that the Ethernet cable connects each cabinet to the other through the respective VPN box or tamper indicating conduits. 3. Acquisition Software Figure 5: "Twin" Mode Configuration The SOS (SMMS Operating Software) suite is used for the SMMS-1 Standard System. This package includes the SOS data acquisition software for data acquisition, the SOS GUI to be used for setting the low pass filter and the calibration software. SOS acquisition software runs different steps: 1) Reading the pressure values from each channel of the manometers. 2) Application of Fast Fourier Transform (FFT) to clean the signal from high frequencies noise (bubbles) - low pass filter. 3) Calculating the bubble frequency. 4) Reporting pressure values, sdt, bubble frequency for each deep tube reading. 4. SOS Calibration Software The SOS calibration Software is used for pressure calibration of the manometers. The software drives in automatic different pressure steps from the portable calibration box, store the calibrator readings against the MENSOR readings, recalculate the calibration coefficients and store them in the MENSOR device.

5 Figure 6. Calibration GUI Figure 7. Portable calibration Box 5. Conclusions 10 instances of the SMMS-1 new design have been installed between 2011 and 2012 at RRP. The upgrade resolved the old system issues related to very low reliability. The benefit of the high redundancy design has been demonstrated with the 100% data availability in the past 3 years of operation. Three campaigns of in-field calibration have been performed successfully reducing the necessary time from 2 weeks to few days and allowing the system to be recalibrated in the field without the manometer replacement, which has high impact on the facility safety requirement.