A Korean APR 1400 for Moorside?

It looks possible that the Korean company TEPCO will take a major stake in the Moorside project. This may involve junking the design and regulatory  work already done on the UK AP1000 (Ref ONR Website) applying to build their own APR 1400 design. That may cause delays but they have a good record of building reactors.

Kepco was formed in 1951, has the brand statement “power with heart” and describes its main business as “Electric power, heat supply, telecommunications and gas supply” (Ref KEPCO website). According to Wikipedia it is just over 50% state owned.

Early news of TEPCO’s interest in Moorside was published in the Guardian in February 2017 (Ref)  More recent news is reported in the FT in July 2017 (Ref). New investment is thought necessary as Toshiba is struggling to survive (Ref).

Korea has a very credible history in the nuclear industry (Ref). The APR1400 being built at Barakah in Abu Dhabi is reported to be 95% complete and receiving nuclear fuel (Ref). But the news that Korea is withdrawing from nuclear power at home (Ref) is a cause for concern.

A one page overview of the APR 1400 reactor can be found at Ref  and a more detailed one at Ref. (See also Ref for a description of the APR+).

The first of these reactors, Shin Kori Unit 3, entered service in December 2016. Reports suggest that 7 further units are under construction and 4 more planned (Ref)) although the recent announcement of a plan to wind down domestic nuclear power (Ref) may have an impact on that programme.

The APR1400 is a 1450 MWe evolutionary PWR based on the Korean Standard Nuclear Power Plant (KSNP) aspiring to provide both enhanced safety and economic competitiveness.

As shown in the circuit diagram below the reactor design has two steam generators but, unusually each of these has two reactor coolant pumps each feeding into a separate cold leg. The pressuriser, attached to one hot leg, and the steam generators are increased in size compared to previous models and the reactor outlet temperature has been dropped to cope better with transients.

From IAEA-CN-164-3S09

Leak before break technology has permitted the pipe restraint system to the simplified.

The Safety Injection System consists of four trains each with a safety injection tank and a safety injection pump. This system provides high pressure, low pressure and recirculation in one system. It injects directly into the Reactor Pressure Vessel to eliminate the potential for leakage from a damaged cold leg. The safety injection pumps are physically separated from each other reducing the probability of common mode failure in fires, sabotage or floods.

A steel lined, post tensioned concrete structure with a reinforced concrete internal layer provides containment, biological shielding and protection from external hazards. It contains the reactor, the reactor cooling circuits, the steam generators and the In-Containment Refuelling Water Storage Plant. The latter is a key safety feature providing cooling water in fault conditions and a large heat sink.

Interestingly the reactor is designed to be able to manage daily load following based on the Korean experience of demand of 100% output for 16 hours a day and 50% output for 4 hours a day with 2 hour power-ramps.

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