Until 1991 designing of the equipment intended to monitor the parameters of process fluids in naval propulsion plants was the responsibility of the Armenian and Georgian Soviet Republics. After the collapse of the Soviet Union, the task was set to establish the basis for development, production, and replacement of Navy equipment in Russia.
Using full-scale prototype facilities NITI developed VHLPT-R and VHLPT-RM instrumented water chemistry laboratories for Russian Navy forces.
VHLPT-R water chemistry laboratory is used for continuous and periodic on-board measurements of the following high-purity water parameters in the secondary system of naval propulsion plants:
- кmass concentration of dissolved salt (for NaCl) up to 5 mg/dm3 with the basic reduced measuring error of ± 2.5 %;
- mass concentration of dissolved oxygen up to 0.5 mg/dm3 with the basic reduced measuring error of ± 6 %;
- mass concentration of chloride-ions up to 0.2 mg/dm3 with the basic reduced measuring error of ±5 %.
VHLPT-R includes a concentration meter, an oxygen meter, and a chloridometer that are connected in one electrical and hydraulic circuit and fixed at the support frame. VHLPT-R operating mode selection is done by the operator manually.
The operation of concentration meter operation is based on measuring a resistive alternating current component and converting it to the respective value of NaCl mass concentration.
The operation of oxygenmeter is based on measuring diffusional threshold current of oxygen reduction and converting it to the respective value of dissolved oxygen concentration.
Chloridometer operation is based on measuring the electromotive force of a galvanic element consisting of two membrane polycrystal chloride-selective electrodes followed by converting the emf to the value of chloride-ion mass concentration.
The above measuring instruments designed for military purposes were approved by Federal Agency for Technical Regulation and Metrology, which is confirmed by Certificate No. 2792.
VHLPT-R instrumented water chemistry laboratory was modified in 2014 to meet the up-to-date military requirements and used for continuous and periodical measurements of high-purity water parameters in the secondary systems of nuclear propulsion plants:
- mass concentration of dissolved salt (for NaCl) in the range from 0.001 to 5.0 mg/dm3;
- mass concentration of dissolved oxygen in the range from 0.001 to 0.5 mg/dm3;
- mass concentration of chloride-ions in the range from 0.001 to 0.2 mg/dm3;
- hydrogen ions activity index from 0 to 12.
VHLPT-RM laboratory is attached to the vertical surface using four shock mounts and connected to the sampling line collector of NPI condensate-feeding system using screw pipe fittings.
The basic VHLPT-RM characteristics are as follows:
- splashproof design;
- 220V, 50Hz AC power supply;
- 50W power consumption ;
- 5000 hours of continuous operation;
- 15-year design life (including storage life).
VHLPT-R water chemistry laboratory includes chemical monitoring instruments, sample preparation devices, valves, pipelines, and electrical cable that connected in one electric and hydraulic circuit housed in a leak-tight metal enclosure.
VHLPT-R operation is carried out using a touch-screen computer that enables:
- mode selection and running;
- displaying and recording of measurement results, operating and technical state parameters of VHLPT-R components;
- warning on parameter limits exceedance;
- failure warning;
- setting of operating and maintenance modes.
Dissolved-oxygen mass concentration is determined by potentiostatic measuring the limiting diffusion current density of molecular oxygen reduction between the electrodes of a membrane amperometric cell and by converting the measured value into the corresponding dissolved-salt mass concentration value accounting for signal temperature compensation.
Chloride-ion mass concentration is determined by measuring the electric cell voltage at zero current and by converting the measured value into the corresponding chloride-ion mass concentration value accounting for signal temperature compensation.
Hydrogen-ion activity is determined by measuring the electromotive force of an electrochemical system consisting of a combination electrode and the analyzed solution. The electromotive force is directly proportional to hydrogen-ion activity in the solution, which allows converting the signal into the hydrogen-ion activity accounting for signal temperature compensation.