CREATE TABLE nuclear_power_plants (id TEXT, name TEXT, latitude TEXT, longitude TEXT, country TEXT, status TEXT, reactortype TEXT, reactormodel TEXT, constructionstartat TEXT, operationalfrom TEXT, operationalto TEXT, capacity TEXT, lastupdatedat TEXT, source TEXT)

What s the most used nuclear reactor model?
SELECT reactormodel FROM nuclear_power_plants GROUP BY reactormodel ORDER BY COUNT(*) DESC LIMIT 1
SELECT "reactormodel" FROM "nuclear_power_plants" GROUP BY "reactormodel" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1