Vesa Riikonen

Lessons learned from the OECD/NEA ETHARINUS joint flagship project on thermal-hydraulic safety

2026

Publication type

A1 Journal article (refereed), original research

Author(s)

Pialla David, Holmstrom Joakim, Salah Anis Bousbia, Adorni Martina, Younsi Amina, Carnevali Sofia, Riikonen Vesa, Schollenberger Simon Philipp

Energy transition

LUT School of Energy Systems

Experimental studies on nitrogen’s effect on reactor core cooling during a hot leg SBLOCA in a scaled EPR model

2025

Publication type

A1 Journal article (refereed), original research

Author(s)

Riikonen Vesa, Kouhia Virpi, Puustinen Markku, Patel Giteshkumar, Räsänen Antti, Kotro Eetu, Hyvärinen Juhani

Energy transition

LUT School of Energy Systems

Flow oscillation fade-out and pool water level effect experiments on open loop passive cooling system

2025

Publication type

A1 Journal article (refereed), original research

Author(s)

Telkkä Joonas, Riikonen Vesa, Räsänen Antti, Kotro Eetu, Hyvärinen Juhani

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

General description of the modified PASI test facility

2025

Publication type

Other

Author(s)

Kouhia Virpi, Riikonen Vesa, Telkkä Joonas, Räsänen Antti, Kotro Eetu, Karppinen Juha

Energy transition

LUT School of Energy Systems

Key Outcomes of Recent NEA Nuclear Safety Joint Projects in Thermal-Hydraulics

2025

Publication type

A4 Conference proceedings

Author(s)

Jacquemain Didier, Adorni Martina, Lee Sangmin, Beilmann Markus, Shollenberger Simon Philipp, Riikonen Vesa, Freixa Jordi, Kang Kyoung-Ho, Perea Miguel Sanchez, Gupta Sanjeev, Freitag Martin, Paladino Domenico

Other focus area

LUT School of Energy Systems

OECD/NEA ETHARINUS project: a flagship project relevant to Thermal-Hydraulic Safety Analysis issues

2025

Publication type

A4 Conference proceedings

Author(s)

Pialla David, Holmström Joakim, Bousbia Salah Anis, Adorni Martina, Younsi Amina, Carnaveli Sofia, Riikonen Vesa, Schollenberger Simon Philipp

Other focus area

LUT School of Energy Systems

Creating the foundations for safe nuclear power in Finland – Thermal hydraulics, safety analyses, safety justification methods research at the LUT University, 2000–2023

2024

Publication type

A1 Journal article (refereed), original research

Author(s)

Hyvärinen Juhani, Riikonen Vesa, Telkkä Joonas, Hujala Elina, Kouhia Virpi, Puustinen Markku, Patel Giteshkumar, Pyy Lauri, Vihavainen Juhani, Suikkanen Heikki, Rintala Ville

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

Experiments on open loop passive cooling of nuclear reactor containment: Quasi-steady-state heat removal, dynamic loads, and feasibility of practical periodic testing

2024

Publication type

A1 Journal article (refereed), original research

Author(s)

Telkkä Joonas, Riikonen Vesa, Kouhia Virpi, Puustinen Markku, Pyy Lauri, Räsänen Antti, Kotro Eetu, Hyvärinen Juhani

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

Frequency and amplitude of flashing-induced instability in an open natural circulation loop

2024

Publication type

A1 Journal article (refereed), original research

Author(s)

Dené Paul, Montout Michael, Garcia Eric, Telkkä Joonas, Riikonen Vesa, David Franck

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

Helical coil steam generator stability experiments with the MOTEL test facility

2024

Publication type

A1 Journal article (refereed), original research

Author(s)

Riikonen Vesa, Telkkä Joonas, Kouhia Virpi, Puustinen Markku, Patel Giteshkumar, Pyy Lauri, Räsänen Antti, Kotro Eetu, Hyvärinen Juhani, Murad Afeef

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

Efficiency of Passive Open Loop Heat Removal over Wide Range of Loop Flow Resistances -- PASI Loop Tests in the EU-PASTELS Project

2023

Publication type

A4 Conference proceedings

Author(s)

Telkkä Joonas, Riikonen Vesa, Räsänen Antti, Kotro Eetu, Hyvärinen Juhani

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

Passive heat exchanger experiments (PAHE)

2023

Publication type

D2 Article in a professional research book (incl. editor’s introduction)

Author(s)

Riikonen Vesa, Kouhia Virpi, Telkkä Joonas, Pyy Lauri

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

PWR PACTEL tests (PATE)

2023

Publication type

D2 Article in a professional research book (incl. editor’s introduction)

Author(s)

Riikonen Vesa, Kouhia Virpi, Telkkä Joonas, Pyy Lauri, Räsänen Antti, Kotro Eetu

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

PASI – A test facility for research on passive heat removal

2021

Publication type

A1 Journal article (refereed), original research

Author(s)

Kouhia Virpi, Riikonen Vesa, Kauppinen Otso-Pekka, Telkkä Joonas, Hyvärinen Juhani

Nuclear Energy and Engineering

LUT School of Energy Systems

PASI – A test facility for research on passive heat removal

2021

Publication type

A4 Conference proceedings

Author(s)

Kouhia Virpi, Riikonen Vesa, Kauppinen Otso-Pekka, Telkkä Joonas, Hyvärinen Juhani

Nuclear Energy and Engineering

LUT School of Energy Systems

PASI facility description for PASTELS

2021

Publication type

Other

Author(s)

Telkkä J, Kouhia V, Riikonen V, Karppinen J, Räsänen A, Kotro E

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

Passive heat exchanger experiments (PAHE)

2021

Publication type

D2 Article in a professional research book (incl. editor’s introduction)

Author(s)

Riikonen Vesa, Kouhia Virpi, Telkkä Joonas, Pyy Lauri

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

PWR PACTEL tests (PATE)

2021

Publication type

D2 Article in a professional research book (incl. editor’s introduction)

Author(s)

Riikonen Vesa, Kouhia Virpi, Pyy Lauri

Energy transition

Nuclear Energy and Engineering

LUT School of Energy Systems

PASI tests for VTT projects

2020

Publication type

Other

Author(s)

Telkkä Joonas, Pyy Lauri, Riikonen Vesa

Nuclear Energy and Engineering

LUT School of Energy Systems

PWR PACTEL Nitrogen Experiment NCG-30

2020

Publication type

Other

Author(s)

Kouhia Virpi, Riikonen Vesa

Nuclear Energy and Engineering

LUT School of Energy Systems

General description of the PWR PACTEL test facility – fourth edition

2019

Publication type

Other

Author(s)

Kouhia Virpi, Riikonen Vesa, Partanen Harri, Räsänen Antti, Kauppinen Otso-Pekka, Telkkä Joonas, Pyy Lauri, Tielinen Kimmo

Nuclear Energy and Engineering

Energy

LUT School of Energy Systems

Integral and separate effects tests on thermal-hydraulic problems in reactors (INTEGRA)

2019

Publication type

D2 Article in a professional research book (incl. editor’s introduction)

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka, Telkkä Joonas

Nuclear Energy and Engineering

LUT School of Energy Systems

PASI - a test facility for research on passive heat removal

2019

Publication type

Other

Author(s)

Kouhia Virpi, Riikonen Vesa, Kauppinen Otso-Pekka, Telkkä Joonas, Hyvärinen Juhani

Nuclear Energy and Engineering

LUT School of Energy Systems

PASI Natural Circulation Test NC-03

2019

Publication type

Other

Author(s)

Telkkä Joonas, Riikonen Vesa

Nuclear Energy and Engineering

LUT School of Energy Systems

PASI test plans

2019

Publication type

Other

Author(s)

Riikonen Vesa, Purhonen Heikki, Kauppinen Otso-Pekka, Kouhia Virpi, Telkkä Joonas, Räsänen Antti, Kotro Eetu, Tielinen Kimmo

Plans for the PWR PACTEL inadvertent opening of SV and MSRT tests

2019

Publication type

Other

Author(s)

Riikonen Vesa, Pyy Lauri

System code analysis of accumulator nitrogen discharge during LOCA experiment at PWR PACTEL test facility

2019

Publication type

A1 Journal article (refereed), original research

Author(s)

Kauppinen Otso-Pekka, Kouhia Virpi, Riikonen Vesa, Hyvärinen Juhani

The PWR PACTEL nitrogen experiments in the OECD/NEA PKL Phase 4 project

2019

Publication type

Other

Author(s)

Riikonen Vesa

Experimental observation of adverse and beneficial effects of nitrogen on reactor core cooling

2018

Publication type

A1 Journal article (refereed), original research

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka, Sjövall Heikki, Hyvärinen Juhani

General description of the PASI test facility, second edition

2018

Publication type

Other

Author(s)

Kouhia Virpi, Riikonen Vesa, Telkkä Joonas, Partanen Harri, Räsänen Antti, Kauppinen Otso-Pekka, Kotro Eetu, Saure Ilkka, Tielinen Kimmo, Karppinen Juha

Nuclear Energy and Engineering

Energy

LUT School of Energy Systems

PASI facility – characterizing experiments

2018

Publication type

Other

Author(s)

Kouhia Virpi, Riikonen Vesa

Nuclear Energy and Engineering

Energy

LUT School of Energy Systems

PWR PACTEL pump trip experiments

2018

Publication type

Other

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka

Nuclear Energy and Engineering

Energy

LUT School of Energy Systems

Integral and separate effects tests on thermal-hydraulic problems in reactors (INTEGRA)

2017

Publication type

D2 Article in a professional research book (incl. editor’s introduction)

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka, Telkkä Joonas

Nuclear Energy and Engineering

Energy

LUT School of Energy Systems

Coupled one-dimensional and CFD models for the simulation of steam generators

2016

Publication type

A1 Journal article (refereed), original research

Author(s)

Hovi Ville, Pättikangas Timo, Riikonen Vesa

Engineering

LUT School of Energy Systems

PWR PACTEL nitrogen experiments

2016

Publication type

Other

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka

PWR PACTEL typpikokeiden alustava koesuunnitelma

2016

Publication type

Other

Author(s)

Riikonen Vesa, Kouhia Virpi

Nuclear Energy and Engineering

LUT School of Energy Systems

ANALYSIS OF REVERSE FLOW IN LOW-RISE INVERTED U-TUBE STEAM GENERATOR OF PWR PACTEL FACILITY

2015

Publication type

A4 Conference proceedings

Author(s)

Kauppinen Otso-Pekka, Riikonen Vesa, Kouhia Virpi, Hyvärinen Juhani

Energy

Engineering

LUT School of Energy Systems

Computer analyses on loop seal clearing experiment at PWR PACTEL

2015

Publication type

A1 Journal article (refereed), original research

Author(s)

Kauppinen Otso-Pekka, Kouhia Virpi, Riikonen Vesa, Hyvärinen Juhani, Sjövall Heikki

Nuclear Energy and Engineering

LUT School of Energy Systems

PWR PACTEL experiments (PAX)

2015

Publication type

D3 Professional conference proceedings

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka, Telkkä Joonas, Purhonen Heikki

Nuclear Energy and Engineering

LUT School of Energy Systems

PWR PACTEL flow reversal experiments

2015

Publication type

Other

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka

Nuclear Energy and Engineering

LUT School of Energy Systems

General description of the PWR PACTEL test facility - third edition, Technical report, PAX 2/2014

2014

Publication type

D4 Published development or research report or study

Author(s)

Kouhia Virpi, Riikonen Vesa, Partanen Harri, Räsänen Antti, Kauppinen Otso-Pekka, Telkkä Joonas, Pyy Lauri

Nuclear Energy and Engineering

LUT School of Energy Systems

Simulations on PWR PACTEL CNC and SBO experiments, Research Report, PAX 3/2014

2014

Publication type

D4 Published development or research report or study

Author(s)

Kouhia Virpi, Kauppinen Otso-Pekka, Riikonen Vesa

Nuclear Energy and Engineering

LUT School of Energy Systems

Station blackout experiments, Research Report, PAX 1/2014

2014

Publication type

D4 Published development or research report or study

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka

Nuclear Energy and Engineering

LUT School of Energy Systems

Benchmark exercise on SBLOCA experiment of PWR PACTEL facility

2013

Publication type

A1 Journal article (refereed), original research

Author(s)

Kouhia Virpi, Riikonen Vesa, Kauppinen Otso-Pekka, Purhonen Heikki, Austregesilo Henrique, Bánáti József, Cherubini Marco, D'Auria Francesco, Inkinen Pasi, Karppinen Ismo, Kral Pavel, Peltokorpi Lauri, Peltonen Joanna, Weber Sebastian

Nuclear Energy and Engineering

LUT School of Energy Systems

BWR Suppression Pool Studies with POOLEX and PPOOLEX Test Facilities at LUT

2013

Publication type

A4 Conference proceedings

Author(s)

Puustinen Markku, Kyrki-Rajamäki Riitta, Tanskanen Vesa, Räsänen Antti, Purhonen Heikki, Riikonen Vesa, Laine Jani, Hujala Elina

Nuclear Energy and Engineering

Energy

Engineering

LUT School of Energy Systems

Cool down under Natural Circulation Conditions in Presence of Secondary side Isolated Steam Generators, Research Report, PAX 1/2013

2013

Publication type

D4 Published development or research report or study

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka

Nuclear Energy and Engineering

LUT School of Energy Systems

General description of the PWR PACTEL test facility, the second edition, Technical report, PAX 2/2013

2013

Publication type

D4 Published development or research report or study

Author(s)

Kouhia Virpi, Riikonen Vesa, Partanen Harri, Räsänen Antti, Kauppinen Otso-Pekka, Telkkä Joonas, Pyy Lauri

Nuclear Energy and Engineering

LUT School of Energy Systems

PWR PACTEL experiments (PAX)

2013

Publication type

D3 Professional conference proceedings

Author(s)

Riikonen Vesa, Kouhia Virpi

Nuclear Energy and Engineering

LUT School of Energy Systems

Three-dimensional CFD model of a NPP steam generator

2013

Publication type

A4 Conference proceedings

Author(s)

Pättikangas Timo, Hovi Ville, Niemi Jarto, Riikonen Vesa, Kouhia Virpi, Purhonen Heikki

Nuclear Energy and Engineering

LUT School of Energy Systems

Validation of RELAP5/mod3.3 against the PACTEL SBL-50 benchmark transient

2013

Publication type

A4 Conference proceedings

Author(s)

Bánáti József, Riikonen Vesa, Kouhia Virpi, Purhonen Heikki

Nuclear Energy and Engineering

LUT School of Energy Systems

Loop seal experiments with PWR PACTEL, Research Report, PAX 1/2012

2012

Publication type

D4 Published development or research report or study

Author(s)

Riikonen Vesa, Kouhia Virpi, Kauppinen Otso-Pekka

Nuclear Energy and Engineering

LUT School of Energy Systems

PACTEL and PWR PACTEL Test Facilities for Versatile LWR Applications

2012

Publication type

A1 Journal article (refereed), original research

Author(s)

Kouhia Virpi, Purhonen Heikki, Riikonen Vesa, Puustinen Markku, Kyrki-Rajamäki Riitta, Vihavainen Juhani

Nuclear Energy and Engineering

LUT School of Energy Systems

Modeling of the PACTEL Facility and Simulation of a Small Break LOCA Experiment With the TRACE V5.0 Code

2011

Publication type

A4 Conference proceedings

Author(s)

Vihavainen Juhani, Riikonen Vesa, Puustinen Markku, Kyrki-Rajamäki Riitta

Nuclear Energy and Engineering

LUT School of Energy Systems

PWR PACTEL experiments at low pressures, Research Report, PAX 3/2011

2011

Publication type

D4 Published development or research report or study

Author(s)

Riikonen Vesa, Kouhia Virpi

Nuclear Energy and Engineering

LUT School of Energy Systems

Study of flow reversing in vertical heat exchange tubes, PAX 4/2011

2011

Publication type

D4 Published development or research report or study

Author(s)

Riikonen Vesa, Kouhia Virpi, Vihavainen Juhani

Nuclear Energy and Engineering

LUT School of Energy Systems

Summary Report OF PWR PACTEL Benchmark Experiment Blind Calculations, Research report, PAX 1/2011

2011

Publication type

D4 Published development or research report or study

Author(s)

Riikonen Vesa, Kouhia Virpi

Nuclear Energy and Engineering

LUT School of Energy Systems

Summary Report of PWR PACTEL Benchmark Experiment Open Calculations, Research report, PAX 2/2011

2011

Publication type

D4 Published development or research report or study

Author(s)

Riikonen Vesa, Kouhia Virpi

Nuclear Energy and Engineering

LUT School of Energy Systems

A New Integral Facility PWR PACTEL for Vertical Steam Generator Simulation

2010

Publication type

A4 Conference proceedings

Author(s)

Rantakaulio Antti, Kouhia Virpi, Riikonen Vesa, Räsänen Antti, Purhonen Heikki, Kyrki-Rajamäki Riitta

Nuclear Energy and Engineering

LUT School of Energy Systems

Cathare Assessment of PACTEL LOCA Experiments with Accident Management

2010

Publication type

A1 Journal article (refereed), original research

Author(s)

Sabotinov Luben, Purhonen Heikki, Riikonen Vesa

Nuclear Energy and Engineering

Energy

Engineering (miscellaneous)

LUT School of Energy Systems

New possibilities to simulate vertical steam generators with integral facility PWR PACTEL

2010

Publication type

A4 Conference proceedings

Author(s)

Kouhia Virpi, Kyrki-Rajamäki Riitta, Purhonen Heikki, Rantakaulio Antti, Riikonen Vesa, Räsänen Antti

Nuclear Energy and Engineering

LUT School of Energy Systems

TRACE code modeling of the horizontal steam generator of the PACTEL facility and calculation of a loss-of-feedwater experiment

2010

Publication type

A1 Journal article (refereed), original research

Author(s)

Vihavainen Juhani, Riikonen Vesa, Kyrki-Rajamäki Riitta

Nuclear Energy and Engineering

LUT School of Energy Systems

General description of the PWR PACTEL test facility, Research Report, YTY 1/2009

2009

Publication type

D4 Published development or research report or study

Author(s)

Riikonen Vesa, Kouhia Virpi, Räsänen Antti, Partanen Harri

Nuclear Energy and Engineering

LUT School of Energy Systems

PACTEL integral test facility - Description of versatile applications

2006

Publication type

A1 Journal article (refereed), original research

Author(s)

Purhonen Heikki, Puustinen Markku, Riikonen Vesa, Kyrki-Rajamäki Riitta, Vihavainen Juhani

PACTEL – A VERSATILE FACILITY FOR RESEARCH OF THERMAL HYDRAULICS

2005

Publication type

A4 Conference proceedings

Author(s)

Purhonen Heikki, Puustinen Markku, Riikonen Vesa, Kyrki-Rajamäki Riitta, Vihavainen Juhani

Steam Blowdown Experiments with the Condensation Pool Test Rig

2005

Publication type

A4 Conference proceedings

Author(s)

Purhonen Heikki, Puustinen Markku, Riikonen Vesa, Kyrki-Rajamäki Riitta, Vihavainen Juhani, Räsänen Antti

Analyses of PACTEL passive safety injection experiments GDE-21 through GDE-25

1998

Publication type

A1 Journal article (refereed), original research

Author(s)

Tuunanen Jari, Riikonen Vesa, Kouhia Jyrki, Vihavainen Juhani

Engineering

LUT School of Energy Systems

RELAP5 Analysis of Gravity-Driven Core-Cooling Experiments with PACTEL

1997

Publication type

A1 Journal article (refereed), original research

Author(s)

Munther Reijo, Vihavainen Juhani, Kalli Heikki, Kouhia Jyrki, Riikonen Vesa

Engineering

LUT School of Energy Systems

Publications and other content

Publications links