Published Tuesday, 10 August 2010
Harrison set a time of 1:49:80 which ensured he made it through to the evening's last four event in Budapest.
The top eight from the semis will then reach Wednesday's final.
It was disappointment, however, for Claire Dawson of Bangor who did not progress from the 100 metre freestyle heats, while Andrew Bree pulled out of the 200 metre Individual Medley heats.
Melanie Nocher missed out on a 200 metre backstroke final after a seventh place finish on Monday.