HIGH TEMPERATURE & PRESSURE CORROSION CRACKING SYSTEM
STUDENT TRAINING PLAN
STANDARD OPERATING PROCEDURE (SOP) INCLUDED
Version 1.0
Center for Nuclear Materials and Fuel Cycle Research
The Ohio State University
Columbus, OH
Date: 10/30/2015
1. Introduction
1.1 Background and Scope
The purpose of the High Temperature & Pressure Corrosion Cracking System is to develop, control and measure stress corrosion cracks under well-defined material and environmental conditions and ensure that the crack growth rate (CGR) response is reproducible and characteristic of the test conditions. The system simulates light water reactor (LWR) environments up to 350 °C at 2500 psi. Features expected in a good crack-growth system include active constant K load control, active temperature control, a sensitive crack length measurement apparatus, a flowing high temperature water system, control over all aspects of water chemistry and continuous monitoring of all pertinent tests parameters.
The Student Training Plan aims to train intended users to acquire all the technical knowledge and safety concerns to independently operate on the system.
1.2 Points of Contact
The system belongs to The Center for Nuclear Materials and Fuel Cycle Research of The Ohio State University. It is located at Scott Lab, W396, 201 W 19th Ave, Columbus, OH.
Role / Name / Contact NumberTraining Manager
2. System Components
The key components of the system include:
1) A servo-electric load control system capable of holding constant load for very long periods of time.
2) A high pressure piston pump to pressurize and flow water through the high temperature loop.
3) An autoclave to sustain samples and solution for experiments.
4) A custom-made water board for precise water chemistry control.
5) A reversing DCPD system for crack length estimation.
6) A continuous data acquisition system.
2.1 Servo-electric load control system
The Interactive Instruments Model 5K Servo Creep Controller is a fully programmable electromechanical load controller system which capable of controlling tensile loads to 5000 lbs. continuous over the 3.25 inch stroke for long periods of time. The control panel can be manually or remotely configured to control the load, stroke or strain control point in real-time. A built-in waveform generator can be programmed to cycle or ramp the control point for hours, days or even months for unattended testing. The system includes the software to remote control and record the loading data.
The procedures to load must refer to the manual that’s placed on the shelf near the system.
2.2 High pressure piston pump
The Pulsafeeder Model 7440 Hydraulic Diaphragm Metering Pump is to precise metering and long-term reliably stroking. It consists of a three-phase powered motor and a liquid end separated by the hydraulically operated diaphragm.
A pulse dampener, which requires sufficient volume, a gas charge of 60% of the operating pressure and a short liquid path to the pulse dampener, is used to eliminate almost all pressure pulsing associated with the pump. The pressure gauge of nitrogen cylinder is to control the stabilizing pressure on target. Pump oil must be changed after a period of time. The first oil change should be done after 6 months of continuous operation and them every 12 months for normal service and every 6 months for severe service. The procedures to change oil can be found on the manual the pump [1].
2.3 Autoclave
The HiP Model 802858 4-Liter Autoclave is made of SS316 to sustain samples and high temperature & pressure solution for experiments. The autoclave contains eight sealing threads and one sealing gasket #206964. The gasket must be replaced once any defect was found or any leaking occurred during high pressure operation if the right procedures have been followed.
2.4 Water board
Figure 1 is the water flow diagram displaying the components and flow direction. After passing through the autoclave and heat exchanger system, the water in the loop operates as usual in a closed loop where the autoclave effluent is continuously demineralized and re-equilibrated for dissolved gases in the glass column. The impurities are added to the glass column from the 10 liters impurity reservoir with a metering pump, at a fixed flow-rate or controlled by the conductivity meter and signal transmitter. Buffered chemistries are created by a pre-conditioning mixed bed demineralizer (full-flow demineralization) to the target chemistry. B/Li chemistries tend to drift in composition because the Fe++ is the most common impurity in hydrogenated water, and the demineralizer releases H+ and Li+ as it absorbs Fe++. The system can compensate for the rise in Li+ level versus time. Two 140 microns filters are connected in the water loop to filter out the large molecular diameter particles. More concentrated chemistries can also be used, but then full flow (demineralized) cleanup of trace impurities is not possible; thus the more concentrated chemistries will not be easily tried.
2.5 Reversing DCPD system
High-resolution, direct current potential drop (DCPD) is used to measure crack length in-situ and enable interactive control of loading conditions.
2.6 Data acquisition system
The computer receives the data from water board conductivity sensors, load control system and DCPD system. Received data include temperature, influent and effluent conductivity, loading frequency, location and force, DCPD current, time/data, etc.
3. Standard Operating Procedure (SOP)
The following procedures show the methods to make the system operate at 300 °C and 2000 psi for corrosion cracking experiments.
1) Exam all the connections are well-connected and sealed. (Note: if any connection leaked during the operation, stop the test immediately and drain all the solution out of the loop. The system cannot be operated at high temperature or pressure until the leaking is solved.)
2) Install the samples and connect the DCPD cables.
3) The way to seal the autoclave: i) lift the autoclave with crane and place on the bottom plate, ii) match the holes of the autoclave body with the threads of bottom plate, iii) install the 8 autoclave threads and tight with fingers, iv) use the electronic torque wrench to tight the threads to 30 ft-lb, 60 ft-lb, 90 ft-lb till 110 ft-lb at the final.
4) Open the valves for solution flow and close the valves for draining.
5) Record the readings of pressure gauges and the flow meter.
6) Inject ultra-pure water till the water level of glass column reaches the top.
7) Close the injection valve.
8) Turn on the powers of pump and micropump.
9) The loop flow rate can be adjusted by the stroke of pump.
10) Slowly increase the loop pressure by turning the back pressure regulator (clockwise) and observe the reading of loop pressure regulator. At the same time, adjust the pressure regulator of compressed nitrogen cylinder to make the discharge solution and the gas balance in the pressure dampener.
11) Once the reading of loop pressure regulator reaches 2000 psi, stop the last step.
12) Turn on the power of heater. Set the target temperature at 300 °C and wait it to heat.
13) Wrap the insulation cover on the heating mantle.
14) Once the temperature reaches 300 °C, record the readings of pressure regulators and the flow meter.
15) Turn on the data acquisition system to receive readings.
16) Turn on the load control system for loading and save the loading data by the software.
17) The chemistries can be injected into the loop by manually controlling or automatically releasing through the Q-pump and conductivity sensors. The injection depends on the objective of the experiment.
18) Exam the system daily to make sure it’s sealed and recorded.
19) At the end of tests, turn off the powers of pump and micropump, close the valve of nitrogen cylinder and open the needle valve under the nitrogen pressure gauge to relieve the residual gas.
20) Thoroughly open the back pressure regulator (anti-clockwise turn).
21) Save the data and quit the data acquisitions. Disconnect the cables from data acquisitions and samples and make them well-keep.
22) Open the needle valve of autoclave and pump to drain the solution.
23) Release the 8 threads of autoclave and life the autoclave with crane.
24) Uninstall the samples and well-keep the autoclave inner components.
25) If chemistries were added during the experiment, rinse the loop with DI water for couple of days till the reading of digital conductivity sensor reduces to the conductivity of ultra-pure water, i.e. below 18 MΩ-cm.
4. Figures
Figure 1 Water flow diagram of the system (include water board). 1- digital pressure gauge, 2- safety head for rupture disk, 3- removable filter, 4- back pressure regulator 4000 psi, 5- 100 psi pressure gauge, 6- digital conductivity sensor, 7- flow meter, 8- cartridge, 9- fiber filter, 10- 10-Liter reservoir, 11- Q pump, 13- glass column, 14- stainless steel plate, 15- micropump, 16- gas tubing, 17- 1 psi check valves, 18- 10 psi check valve, 19- conductivity sensor transmitter.
Figure 2 Schematic of DCPD system.
APPENDIX A: Training Plan Approval
The undersigned acknowledge that they have reviewed the High Temperature & Pressure Corrosion Cracking System Training Plan and agree with the information presented within this document. Changes to this Training Plan will be coordinated with, and approved by, the undersigned, or their designated representatives.
Signature: Date:
Print Name:
Title:
Role: Training Manager
APPENDIX B: REFERENCES
The following lists displays the articles referenced in this document.
[1] / "PULSA Series diaphragm metering pumps installation operation maintenance instruction".1