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IDEAL – Infrastructure development at LUT safety research laboratory and LUT Thermal Hydraulics Laboratory presentation

Joonas Telkkä

Project Researcher | LUT University

[email protected]

SAFIR2022 MIDTERM SEMINAR

INTRODUCTION TO THE IDEAL PROJECT


Main goals

Develop the thermal hydraulic infrastructure at LUT University

Secure the operability of the existing test facilities, and build new

Safety significance

Experiments reveal things you did not know!

Large test facilities require maintenance and development

New measuring techniques produce highly detailed data for

▪ understanding of safety-relevant flow phenomena

▪ development and validation of computational tools

Deployment and utilization of the techniques must be practiced

Experimental infrastructure and expertise – labs, skill, staff, stuff –

enable rapid solution of problems that arise in the Finnish NPPs

THE IDEAL PROJECT


WP1: Development of instrumentation

T1.1: Development of advanced measurement techniques

T2.2: Acquisition and implementation of new measurement techniques

WP2: Maintenance of test facilities

T2.1: Maintenance actions

T2.2: Procurement of equipment

WP3: Process control and computational systems

T3.1: Renewing of the field and process instrumentation

T3.2: Upgrade of the computational servers

T3.3: Enlargement of the data storage space

WP4: Development of the MOTEL test facility

T4.1: Assembling and erecting of the first version of MOTEL

T4.2: Design and construction of the next versions of MOTEL

T4.3: Shakedown tests of MOTEL

WP5: Project management

T5.1: Project management

T5.2: Participating in the SAFIR 2018 final seminar

T5.3: International co-operation

IDEAL WP1: DEVELOPMENT OF INSTRUMENTATION

PIV

Particle Image Velocimetry

(PIV)

Velocity field (2D/3D)

Also time-dependent WMS

Wire-Mesh Sensors (WMS)

2D fields:

▪ Void fractions

▪ Passive scalars

Bubble velocities

HSC

High-Speed Cameras (HSC)

Tracking of fast, visible phenomena

(e.g. steam condensation)

Pattern recognition

Multidimensional measurements for multidimensional modelling

Improved understanding and modelling of flow phenomena

Experiment

Opt. Fibre

Optic fibers

Temperature or strain

1D distributions at kHz

range,

< mm resolution up to 20 m




Testing of the optic fibers for 1D temperature distribution measurement

In 2019, the fibers were tested in the water pool of the PASI facility → results not convincing, bends of the capillary pipes affecting the results?

In 2020, the technique was further tested as a bachelor’s thesis work

▪ Measurements in a simpler set-up → water pool, static water, isothermal conditions

▪ Study of the effect of the capillary pipe bends

▪ Study of the effect of vibration of the measurement system

▪ Study of the effect of temperature → measurements with cold (~10-20 °C) and hot (~50 °C) water

▪ Spatial resolution of the measurements 0.65 mm (max.)

1. Measurement with three fibers

2. Measurement with one fiber and multiple bends

Example result from the testing in

the PASI facility water pool

Measurement set-up

of the further testing

in the water pool of

the HIPE test facility

Schematic of the

three-fiber set-up

Schematic of the

one-fiber set-up



Testing of the optic fibers for 1D temperature distribution measurement

Example of a measurement result with the

straight fiber (red dots are the reference

thermocouple measurement values)

▪ Grey dots are time averages of the individual

fiber measurement points (spatial resolution

0.65 mm)

▪ Deviation of the values is relatively large,

even though there were no bends


fiber with two bends (after shaking)

▪ Fiber gives in average smaller values

than the thermocouples

▪ Deviation even larger, ~3 degrees

(shaking makes the error a bit larger)

▪ Error in the fiber measurement, although

“cold” water was used


fiber with six bends

▪ Really big differences between fiber and

reference measurements (even 4-5 deg.)

▪ Effect of the bends difficult to interpret from

the results of this work

IDEAL WP2: MAINTENANCE OF TEST FACILITIES


The work package includes maintenance and repair works of the test facilities in the LUT laboratory

Highlights in 2019-2020:

Annual outages – calibrations of instruments, periodic pressure vessel inspections

Renovation actions of the laboratory

▪ Gratings and railings of the PACTEL laboratory renewed

▪ Compressed air system renewal

▪ Electrical system renewal begun in 2020

PASI facility steam supply system renewed → steam line from PACTEL to the new laboratory

Planning of the component stock

▪ To ensure the ability to construct new testing systems that require components with long delivery times without any delays

▪ Components include mechanical components, such as valves, instrumentation and maintenance components

IDEAL WP3: PROCESS CONTROL AND COMPUTATIONAL SYSTEMS


The amount of data from the experiments has been expanded due to advanced and high-speed measurement capabilities

Enlargement of data storage space has been executed jointly with LUT internal investment project

Data storage will be done tripartitely in the future (see figure below)

▪ New data storage servers have been purchased

Also, upgrade of high-performance computing infrastructure has been realized

▪ New computing servers have been purchased → located in conjunction with the data storage servers in new centralized data storage room

Traditional

EDS storage

system

FairData cloud

service of CSC

Long-time storage

for traditional data

Long-time storage

for larger amounts

of data (PIV etc.)

HPC servers

Data storage during

experiments/calculations

Measurement

computersNew

centralized

data storage

Temporary

storage for large

data sets

IDEAL WP4: DEVELOPMENT OF THE MOTEL TEST FACILITY


The first configuration of the MOTEL (MOdular TEst Loop) facility – MOTEL SMR – was assembled during 2019-2020 together with an Academy of Finland funding

In 2019, the framework and the facility itself were erected in the laboratory

▪ All the components and instrumentation were installed

In 2020, final installation works were done

▪ Insulation, final pipe works and auxiliary systems

Shakedown test was conducted in December 2020

▪ To ensure that instrumentation and process control work

Commissioning test in December 2020

▪ Testing of operation of pressure-related safety equipment → safety automation against over-pressurization, core overheating protection

Installations of thermoelements

to the steam generator tubes

Helical coil steam generator and

the secondary collectors inside

the pressure vesselCore with 132 heating rods, 16

instrumentation rods and 145 dummy rods

IDEAL WP4: DEVELOPMENT OF THE MOTEL TEST FACILITY


MOTEL assembling

in the factory

MOTEL assembling to its framework

in the LUT laboratory

MOTEL steam

generator module

LUT THERMAL HYDRAULICS LABORATORY PRESENTATION


MOTEL – studies on the SMR behavior

PASI – studies on the passive heat removal

Condensation studies

Existing old facilities – PWR PACTEL and PPOOLEX

MOTEL – STUDIES ON THE SMR BEHAVIOR


The first MOTEL (MOdular TEst Loop) version – MOTEL SMR – models the functioning of a SMR (similar to that of NuScale SMR)

Total height ~7.7 m, width ~0.7 m, natural circulation

Comprises three changeable modules

1. Core (general representation of a fuel bundle)

2. Steam generator (unique helical coil type)

3. Pressurizer (two 30 kW heaters)

Design pressure/temperature 40 bar/250 °C

Main research interests:

▪ Functioning of SMR

▪ Behavior of the helical coil steam generator

▪ 2D/3D phenomena in the core (not been possible with traditional integral test facilities with thin cores)

Current situation:

▪ Shakedown tests and the commissioning test done in the end of 2020

▪ Characterizing experiments show that distortions due to pressure and heat losses are much less than in traditional IET facilities

▪ MOTEL will be used in the EU-funded McSAFER project → helical SG behavior, core cross flow tests (mixing between subchannels)

Pressurizer

Steam

generator

Core

Secondary

water in

Secondary

steam out

PASI – STUDIES ON THE PASSIVE HEAT REMOVAL

PASI represents an open passive heat removal loop

The reference system is the passive heat removal system for containment (PHRS-C) designed for the AES-2006 type PWR

PASI comprises containment vessel, heat exchanger, riser and downcomer lines, sparger, water pool

▪ Height scaling 1:2 → height of the loop 9.9 m

▪ Maximum pressure inside containment 5 bar

▪ Maximum temperature inside containment 170 °C

PASI has been used in the SAFIR PAHE project and in an industrial contract research with a Finnish customer

▪ Characteristics and dynamics of the system, natural circulation behavior, loop oscillations,…

PASI is one of the two central elements in the EU-funded PASTELS project to study the behavior of passive systems and provide code validation data

▪ Stationary performance of the system → sensitivity to loop friction, effect of pool water level, effect of different sparger structures

▪ Transient performance → startup transient, water pool refill


PASI – STUDIES ON THE PASSIVE HEAT REMOVAL


New water pool New sparger

PASI in the

laboratory

CONDENSATION STUDIES

LUT has good capabilities and readiness to conduct condensation experiments

Condensation studies of LUT have continued with studies in a separate effects facility, SEF-POOL

▪ Characteristics of small-scale condensation phenomena, which affect the effective momentum sources in case of steam injection into a sub-cooled water

▪ Data for validation of simplified EHS/EMS models proposed and developed by KTH (Sweden)

▪ Understanding of the interfacial area behavior → tests support the DCC model development and interfacial area models of CFD codes for steam injection through spargers

LUT has good high-speed imaging capabilities

High-speed cameras have been used in the SEF-POOL tests → the HSC data has been used to develop the in-house built pattern-recognition algorithm

▪ Automatic procession of large amount of dynamic data to extract the interfacial area information (bubble velocity, acceleration, diameter,…)

High-speed camera attached to the SEF-POOL test facility

Steam condensation in cold water (2800 frames/s)

Steam condensation in hot water (2800 frames/s)


EXISTING OLD FACILITIES

The PWR PACTEL facility still in active use

▪ In the SAFIR PATE project

▪ In the OECD/NEA ETHARINUS project to complement the PKL experiments in selected topics → studies on SB-LOCA, one experiment with a hot-leg break, one with a cold-leg break

▪ Readiness for vertical steam generator investigation

▪ Old horizontal steam generators (VVER) still on place

The future of the PPOOLEX facility is open

▪ BWR containment phenomena studies can be continued, if needed

▪ Facility can be re-configured to represent a reactor pressure vessel

▪ RPV downcomer experiments (mixing phenomena)

▪ SMR applications; e.g. inherent heat removal from large vessel outer surfaces

PWR PACTEL

PPOOLEX


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