Members of the GMB and Unite unions were preparing for industrial action after they rejected the previous pay offer made by EDF.
However, under the improved pay deal, wages will be up to 36% above the minimum industry-agreed pay rates and holiday, overtime and pension contribution rates will also increase.
Workers will also receive back pay from the period between 1st January 2017 and 31st May 2017, when the interim bonus scheme was introduced.
Phil Whitehurst, GMB National Officer said: “GMB members have voted, in a very positive and responsible manner, to accept EDF’s final offer.
“Let’s now hope that an open and transparent relationship will precipitate from this on the civil construction phase of HPC.”