Design, development and performance testing of fast response electronics for eddy current flowmeter in monitoring sodium flow Poornapushpakala S. a,1 , Gomathy C. b,2 , Sylvia J.I. c,3 , Babu B. c,3 a Department of Electronics & Control Engineering, Sathyabama University, Chennai 600119, India b Department of Electronics and Communication Engineering, SRM University, Vadapalani, Chennai 600026, India c Head, ID&SS, FRTG, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, India article info Article history: Received 29 March 2013 Received in revised form 15 March 2014 Accepted 2 May 2014 Available online 21 May 2014 Keywords: Eddy current flowmeter Programmable system on chip Sodium velocity Signal conditioning circuit Fast response abstract The paper discusses the design, development and performance tests of a fast response processing electronics for an eddy current flowmeter that has been developed indigenously to measure sodium flow in the primary sodium pump discharge line, pumping liquid sodium to the core consisting of fuel sub- assemblies in the prototype fast breeder reactor at Kalpakkam, India. Liquid sodium is the main coolant in Fast Breeder Nuclear Reactor. Eddy current flowmeters are deployed in liquid metal cooled fast reactors. The measurement of flow rate of the coolant is important to maintain the overall performance of the pump which in turn is the safety requirement of the system. The faster response of the measuring system is required to ensure the protection of the reactor under pump seizer and discharge pipe rupture. This work mainly focuses on the reduction of response time of signal processing electronic delay. & 2014 Elsevier Ltd. All rights reserved. 1. Introduction Sodium flow measurement is imperative in the context of Fast Breeder Reactors (FBR) to check the operation and safety of the reactors. In sodium cooled FBR, various types of flowmeters are employed for sodium flow measurement. Permanent Magnet Flowmeters (PMFM) are widely used for sodium flow measure- ment at the primary pump outlet in BN 350 loop type, by pass line in BN 600 and BN 800 pool type reactor [1]. PMFM is also been used in the primary circuit of Phenix reactor [2]. Fast flux test facility (FFTF), SNR 300, KNK, MONJU, Rapsodie and Fast Breeder Test Reactor (FBTR) [3]. These flowmeters are not suitable for use in regions of high radiation because of the damage to the magnets [4]. In addition, the magnets must be stabilized against the influence of demagnetization, temperature and mechanical shocks and these are heavier in nature [5]. In JOYO a loop type reactor, saddle coil flowmeter is in use in the primary circuit [3] and in the secondary circuit [6]. Saddle coil flowmeters have been used in the secondary circuit of Prototype Fast Reactor (PFR) [7,8]. Saddle coil flowmeters are comparatively lighter but are lengthy [9]. Hence it is not suitable for remote locations. Lehde and Lang [10] patented the flow measurement device based on eddy current principle in 1948. The device consists of two primary coils excited by an AC generator and is placed in such a way that their magnetic effects oppose each other. The second- ary coil is placed midway between the other two coils. These are placed in the insulated material housing. The device is centrally located to a tube where the conducting liquid flows. The resultant voltage induced in the secondary coil is directly proportional to the speed of the fluid. An alternate design with two primary coils in series and two secondary coils in series opposition was devel- oped. A modified design adopting the first technique with 3 pri- mary coils and 2 secondary coils was used as speed and distance measuring instrument for ships. This concept was proposed as a flow failure alarm in the British PFR in the early 1960s [11]. Probe type eddy current flowmeter (ECFM) has been used in the British PFR [12]. ECFM has been developed and used in Hanford Engineering Development Laboratory (US), Argonne National Laboratory (US) and in Indira Gandhi Centre for Atomic Research (IGCAR, India) for monitoring the flow of sodium through the core in a Nuclear Reactor. The ECFM is used for void detection in the Liquid Metal FBR (LMFBR) core exit at O-arai Engineering centre (Japan) [13]. A conceptual design of a contactless ECFM for liquid metal flows Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/flowmeasinst Flow Measurement and Instrumentation http://dx.doi.org/10.1016/j.flowmeasinst.2014.05.004 0955-5986/& 2014 Elsevier Ltd. All rights reserved. E-mail addresses: poornapushpakalas@gmail.com, poornapushpakala.enc@sathyabamauniversity.ac.in, s_ppk@rediffmail.com (S. Poornapushpakala), cgomathy@yahoo.co.uk (C. Gomathy), sylvia@igcar.gov.in (J.I. Sylvia), bbabu@igcar.gov.in (B. Babu). 1 Tel.: þ91 9790956400, þ44 24503165. 2 Tel.: þ91 9444287670. 3 Tel.: þ91 44 27480500. Flow Measurement and Instrumentation 38 (2014) 98–107