"The big duck spent the summer at the beach."
Translation:큰 오리가 해수욕장에서 여름을 지냈어요.
Koreans usually translate 'beach' as '해변'. '해수욕장' is acceptable, but it normally means a sandbeach with leisure facilities.
"Sandbeach with leisure facilities" is a pretty elaborate way of describing what many Americans including myself refer to as a "beach."
In 해수욕장, "장" is place in Sino korean. So 해변 is more like pure korean. Both are correct and used often =)