The US Atomic Safety and Licensing Board has upheld an amendment for the single-unit Seabrook nuclear power plant’s operating licence, but has imposed four additional conditions, the Nuclear Regulatory Commission said.

The amendment, requested by NextEra Energy Seabrook in 2016, relates to monitoring the physical impact the alkali-silica reaction (ASR) will have on the safe operation of the plant as it ages. The ASLB concluded the additional conditions are necessary to ensure adequate health and safety protections for the public.

The C-10 Research and Education Foundation, a nuclear watchdog funded by the state of Massachusetts to monitor Seabrook Station, had filed 10 proposed contentions regarding the amendment. The group is contesting the licence amendment granted by the NRC which saw NextEra’s operating licence at Seabrook extended to 2050. It is is challenging how NextEra will mitigate ASR in the Seabrook facility’s concrete over the coming decades.