在这道题中first是一般过去时的标志么？

The utility company has announced that it will permanently close its Unit I nuclear power plant, the first plant that had been built by private industry and the model for a generation of modern nuclear reactors.

看到这道题的旁边记着first搭配一般过去式，貌似是在新东方上课时记得笔记，但是现在也记不清了。请问NN们，有这样一种说法么？（original搭配一般过去式这个是知道的）

 it will permanently close its Unit I nuclear power plant说明nuclear power plant已经是存在的.与first 无关,