W. Zhang, R.K. Ratnayake, M. Shaver, J. Johns, K. Welter, Fast Neutron Flux and DPA Rates in NuScale SMR Core Components and Vessel, Accepted for publication, ISRD, May 2017 (Accepted for publication)

R. K. Ratnayake, Fueling NuScale, presentation at the 43rd Utility Fuel Reliability and Performance Conference, June 2016

Designed and taught the course “Introduction to Nuclear Engineering”, a final year engineering course at the faculty of Engineering, University of Peradeniya, Peradeniya, Sri Lanka in the capacity of a visiting lecturer, April – June, 2016

Designed and taught the course “Introduction to Nuclear Engineering”, a final year engineering course at the faculty of Engineering, University of Peradeniya, Peradeniya, Sri Lanka in the capacity of a visiting lecturer, April – June, 2015

R. K. Ratnayake, New Generation Nuclear Power -Small Modular Reactor Design, Inaugural lecture, Institute of Engineers Sri Lanka, Colombo, Sri Lanka, January 2014

R. K. Ratnayake, Small Modular Reactor Performance and Safety, public lecture, University of Peradeniya, Sri Lanka January 2014

M.S. Bradbury, R.K. Ratnayake, Radial Nodalization Sensitivity in the Subchannel Code VIPRE-01, 2013 ANS Winter Meeting and Nuclear Technology Expo, Washington DC, November 2013

R.K. Ratnayake, VIPRE-01 pre-submittal meetings, US. Nuclear Regulatory commission, Rockville, MD, 2012, 2013

R. D. Stewart, R. K. Ratnayake and K. Jennings, Microdosimetric model for the induction of cell killing through medium-borne signals, Journal of Radiation Research, 165, 460-469, 2006

R. K. Ratnayake (presenting author) and R. D. Stewart, Analysis of medium transfer, microbeam and broad parallel beam experiments using intercellular signaling models, Radiation Research Society Meeting. Denver, Colorado, 2005 

R. K. Ratnayake (presenting author) and R. D. Stewart, Effects of intercellular signaling on apoptosis, The International workshop on Frontiers in Targeted Radiation Therapies, Purdue University, 2005

R. K. Ratnayake, V. A. Semenenko and R. D. Stewart, Retrospective analysis of DSB rejoining data collected using warm-lysis PFGE protocols, Int. J Radiat. Biol. 2005

R.D. Stewart and R.K. Ratnayake, Implications of intercellular signaling for the shapes of dose-response relationships., DOE Low Dose Program Workshop V, Washington DC, 2005

R.D. Stewart, V.A. Semenenko, and R.K. Ratnayake, Fast Monte Carlo Models to Simulate the Formation and Excision Repair of DNA Damage,  Presented at the VIIth International Workshop on Radiation Damage to DNA, (M. Weinfeld and D. Murray, Chair). Banff, Canada, 2004

R.D. Stewart, R.K. Ratnayake and V.A. Semenenko, DNA Repair and the Mutagenic and Cell Killing Potential of Singly and Multiply Damaged DNA Sites, presented at the Symposium of Modeling and Experimental Approaches to Understanding DNA Damage, Repair and Their Consequences in Cell Biology, Denver, Colorado , 2004

R.K. Ratnayake, L.E. Hochreiter, J.M. Cimbala, K.N. Ivanov, Experimental Study of Two Phase Flow Behavior Past BWR Spacer Grids: ISBN: 0791835898
Publisher: ASME, ICONE 10- 22198, 2002

R. K. Ratnayake, L.E. Hochreiter, S. Ergun, A.J. Baratta, Identification and Ranking of Phenomena leading to Peak Cladding Temperatures in Boiling Water Reactors during Large Break Loss Of Coolant Accident Transients: ISBN: 0791835898, Publisher: ASME, ICONE 10 - 22288, 2002

R.K. Ratnayake (presenting author), L.E. Hochreiter, J.M. Cimbala, K.N. Ivanov, Experimental Study of Two Phase Flow Behavior Past BWR Spacer Grids: ICONE 10, Arlington, Virginia, 2002

R. K. Ratnayake and L.E. Hochreiter, COBRA-TF – A Thermal-Hydraulics Code for Transient Analysis. Version COBRA-TF_SIEMENS_V3 for: Framatome-ANP, Erlangen, Germany, 2002

R. K. Ratnayake (presenting author), L.E. Hochreiter, S. Ergun, A.J. Baratta, Identification and Ranking of Phenomena leading to Peak Cladding Temperatures in Boiling Water Reactors during Large Break Loss Of Coolant Accident Transients: ICONE 10, Arlington, Virginia, 2002

L.J.S. Allen, D.A. Flores, R.K. Ratnayake and J.R. Herbold, Discrete-time deterministic and stochastic models for the spread of rabies, Applied Mathematics and Computation 132(271-292), 2002

R.K. Ratnayake (presenting author), Anthony J. Baratta, L.E. Hochreiter, Code advancements, Annual TRAC conference, Quarnavaca, Mexico, 2000

R.K. Ratnayake, S. Ergun, Anthony J. Baratta, L.E. Hochreiter, Best Estimate BWR Validation Matrix For the Phenomena Identification and Ranking Table, (Nuclear Safety Center, TRAC user group), 2000

R. K. Ratnayake, L. E. Hochreiter, An Outline Of Different Uncertainty Methods For Calculating The 95th Percentile Peak Cladding Temperature With Best-Estimate Thermal Hydraulic Code, (TRAC user group), 2000

R.K. Ratnayake, L.J.S. Allen, Mathematical modeling and analysis of spatial spreading of rabies, American Mathematical Society proceedings, Dallas, Texas, 1998

R.K. Ratnayake (presenting author), Mathematical modeling and analysis of spatial spreading of rabies, American Mathematical Society, Dallas, Texas, 1996

R.K. Ratnayake (presenting author), A novel concept of passive air conditioning, Presented at the University of Peradeniya, Peradeniya, Sri Lanka, 1995

R.K. Ratnayake, J.A.J. Perera, A new UV radiation proof roofing material from un-recyclable paper and bitumen. Ceylon Institute of Industrial and Scientific research, Sri Lanka (1992) (Recognized as the best student research project in 1992/1993)