Moisture separator reheater

Downcomers (diameter 300mm) 31 Moisture separator/reheater... 

The ABWR uses a large turbine with last stage buckets turbine is lower than that of the turbines with 41-inch resulting in an improvement of more than 25MW in buckets, together with moisture separator reheaters and has improved plant thermal efficiency from 33.4% to 34. fabricated from an ingot of 630 tons is used for the rotor... 

The two moisture separator reheaters (MSR) are integral components in the main turbine system. Each MSR has a single stage of reheat. The system is designed to allow operation with one MSR in service. 

Steam generated in the steam generators is supplied to the high-pressure turbine via the main steam header. Steam, leaving the high pressure turbine, passes through 2 combined moisture separators/reheaters prior to entering the three low-pressure turbines. 

This arrangement implies only one 600 MWe turbogenerator set for a plant with three reactor modules. (The alternative configuration features a 200 MWe turbogenerator set for each module which, in this case, includes a high pressure turbine, a moisture separator/reheater and a low pressure turbine). 

The turbine K-160-4.2 consists of a single - flow high pressure cylinder, and double-flow low pressure cylinder that exhausts to the condenser. The two moisture separator/ reheaters are integrated in the main turbine system. The reactor plant is combined with one turbine generator designed for base load and load-following operation. 

This system consists of the pipes and valves that take the steam from each steam generator to the stop valves of the high-pressure turbine. It diverts a proportion of the steam to the to the moisture-separator reheater (Section 6.6.5) and a small amount of steam to seal the low-pressure turbine glands (Section 6.6.7). There is also a turbine bypass coimection, which allows the steam to be dumped directly into the main condenser (Section 6.6.8) without passing through the turbine. 

After expanding through the high-pressure turbine, the exhaust steam is wet and at saturation temperature. It is routed through two external moisture separator-reheater vessels where it is dried and superheated.. The external moisture separators reduce the moisture content of the high-pressure exhaust steam from approximately lOto 13 percent at the rated load to 0.5 percent or less moisture. It uses multiple vane chevron banks for the moisture removal. The moisture removed drains to a moisture-separator drain tank, from where it is pumped to the deaerator, which is at similar pressure to the steam entering the low pressure turbine. 

Steam to the moisture separator reheaters and to the feed water heaters when main steam is unavailable. 

Applications include heat exchangers, condensers, feed-water heaters, tube-oil coolers, and moisture-separator reheaters. 

In the turbine system design, the TCDF-38 system composed of a single high-pressure turbine and single low-pressure turbine is adopted for the 300 MW(e) RMWR with the cascade heater drain system and without the moisture separator-reheater. This is because system simplification takes priority over improvements in the thermal efficiency. Furthermore, redundancy in the condensate and feedwater system (i.e., back-up pump and heater train) is eliminated because the risk of electric generation loss is lower in the small power plant. 

The Canadian SCWR concept is a pressure-tube type of concept. It adopts the direct cycle, which includes a 2540-MWth core that receives feed water at 315°C and 1176 kg/s and generates supercritical steam at 625°C and 25 MPa. The cycle includes steam reheat using a moisture separator reheater (MSR) between the IP turbine and LP turbine. The MSR separates the moisture from the steam and reheats the steam to ensure an acceptable moisture level at the outlet of the LP turbine. Four LP condensate heaters are included in the cycle as well as a deaerator and four HP feed-water heaters. The gross electrical output is calculated as 1255 MWg, giving a gross thermal efficiency of 49.4%. A schematic diagram of the direct cycle is shown in Fig. 8.4 (Zhou, 2009). 

Figure 8.4 Schematic of direct steam cycle with a moisture separator reheater in a supercritical water-cooled reactor plant. HPT, high-pressure turbine IPT, intermediate-pressure turbine LPT, low-pressure turbine CEP, condensate extraction pump LP, low pressure HP, high pressure FWP, feed-water pump.

The No. 2 main feedwater pump turbine, deprived of steam, was slowly winding down. Since the MSIVs were closed and there was limited steam inventory in the moisture separator reheaters, there was inadequate motive power to pump feedwater to the steam generators. At about 1 40 a.m., the discharge pressure of the pump had dropped below the steam pressure which terminated main feedwater flow. 

In the Super LWR plant, the main steam from the core is fed to the HP turbine. At the HP turbine, regenerative steam is extracted from two points to be led to the first and second HP feedwater heaters. Before entering the HP turbine, part of the main steam is also extracted for the second reheater. Then, the steam exhausted from the HP turbine enters the IP turbine, where regenerative steam is extracted from two points to be led to the third and fourth HP feedwater heaters. The steam out of the IP turbine is fed to the moisture separator reheater, where its wetness is separated and then reheated twice to be superheated steam. Finally, the steam enters the LP turbines, where regenerative steam is extracted from four points and led to four LP feedwater heaters. The steam out of the LP turbines is condensed to water in the condenser. The water is pressurized by the LP condensate pumps and mixed... 

A moisture separator reheater with two reheating stages, between the IP and LP turbines... 

Jack H. Karian (212) 591-8552 PTC 12.3 Deaerators Jack H. Karian (212) 591-8552 PTC 12.4 Moisture Separator Reheaters Jack H. Karian (212) 591-8552 PTC 12.5 Sin e Phase Heat Eixchangers Geoige Osolsobe... 

---