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Minsmere is a nature reserve owned and managed by the Royal Society for the Protection of Birds (RSPB) at Minsmere, Suffolk. The 1,000-hectare (2,500-acre) site has been managed by the RSPB since 1947 and covers areas of reed bed, lowland heath, acid grassland, wet grassland, woodland and shingle vegetation. It lies within the Suffolk Coast and Heaths Area of Outstanding Natural Beauty and the Suffolk Heritage Coast area. It is conserved as a Site of Special Scientific Interest, Special Area of Conservation, Special Protection Area and Ramsar site.

The nature reserve is managed primarily for bird conservation, particularly through control and improvement of wetland, heath and grassland habitats, with particular emphasis on encouraging nationally uncommon breeding species such as the bittern, stone-curlew, marsh harrier, nightjar and nightingale. The diversity of habitats has also led to a wide variety of other animals and plants being recorded on the site. Before becoming a nature reserve, the area was the site of an ancient abbey and a Tudor artillery battery. The marshes were reclaimed as farmland in the 19th century, but were re-flooded during World War II as a protection against possible invasion.

The reserve has a visitor centre, eight bird hides and an extensive network of footpaths and trails. Entry is free for RSPB members. Potential future threats to the site include flooding or salination as climate change causes rising sea levels, coastal erosion and possible effects on water levels due to the construction of a new reactor at the neighbouring Sizewell nuclear power stations. The area around Minsmere consists of the wide valley of the Minsmere River with Dunwich cliffs to the north and Sizewell cliffs to the south. Two extensive sandbanks lie off the coast, and the beach is sand overlain with shingle.The cliffs have a maximum height of about 17 m (56 ft) and are amongst the most rapidly eroding in the UK, at an annual rate of 1–2 m (3.3–6.6 ft).

From 500 BC to 700 AD, the sea level in Suffolk was about 6 m (20 ft) higher than it is today, and the low-lying areas of the present coast were then tidal estuaries. The river mouth was finally closed in the 18th century as sand and shingle deposits formed off the coast. The higher land consists of a deep layer of gravel and sand, the legacy of the beach formed by the sea before it retreated. The geology of the wetland areas below the topsoil is marine clay with darker freshwater deposits from the Minsmere River. In the Domesday Survey in 1086 Minsmere was known as Menesmara or Milsemere. It is recorded as having six households headed by freemen with one plough team. The manor, which was in the Hundred of Blythling, was held by Roger Bigot.

Ranulf de Glanvill, King Henry II's Lord Chief Justice, founded a Premonstratensian abbey on the marshes at Minsmere in 1182. The area was embanked to protect the abbey from the sea and to reclaim farmland, but still suffered several years of severe flooding in the 14th century. The site was abandoned in 1363, and the stone from the buildings was used to rebuild Leiston Abbey at a new location 3.3 kilometres (2.1 mi) further inland. The remains of the abbey church, fish pond and other buildings can still be detected below ground, but the only visible structure is the ruined chapel of St Mary, built within the nave of the former church. The lower section of the chapel was built soon after the demolition of the abbey in 1363, and the brick upper parts are thought to have been added by former abbot John Green, who lived there as a hermit when he retired from his post in 1527. The site was abandoned in 1537 during the Dissolution of the Monasteries, the only further construction being a pillbox that was built inside the chapel during World War II. The ruins are a scheduled monument of national importance.

Peat cutting took place at Minsmere from at least the 12th century, and a 1237 description of the coastline describes Minsmere as a port. In a survey of 1587, an early Tudor period artillery battery, constructed sometime after 1539 at Minsmere, was in ruins; the survey recommended that it be rebuilt. A coastguard station operated at Minsmere in the 1840s in an attempt to control smuggling along this stretch of the coast.

In about 1780 a sandbank closed the mouth of the Minsmere River, creating a large freshwater wetland on its inland side. The reeds that grew there were cut for thatching, and access was improved by using sand from the higher alluvial areas to build tracks across the marshes. These marshes were enclosed and drained for agricultural use in 1812 and 1813, following the passing of the relevant Act in 1810, with the main sluice being built to control drainage to the sea. The New Cut, a canal south of the river, was built as part of the drainage works, joining the river again at the sea sluice. The canal was used to transport the thatch crop inland by barge, its bridges being built particularly high to enable the bulky cargo to pass beneath. The drainage was improved after 1846 using steam-powered pumps. These were made by Richard Garrett & Sons of the Leiston Iron Works.

There were four windmill sites on the levels. The Eastbridge Windpump was a smock mill built in the mid-19th century, probably by the millwright Robert Martin of Beccles. It stood north of the New Cut. The mill worked a three throw pump with square pistons. The windpump was working until 1939 and collapsed in February 1977. The remains were rescued by the Suffolk Mills Group in July 1977 and the mill was rebuilt at the Museum of East Anglian Life in Stowmarket in the early 1980s. The Sea Wall Mill stood north of the New Cut but closer to the coast than the Eastbridge Windpump. It was a smock mill built in the early 19th century. The mill worked by wind until it was tailwinded in January 1935, breaking the windshaft and rendering the mill sail-less. The scoopwheel was subsequently worked by a Hupmobile petrol engine, and later by a diesel engine. The mill collapsed in the summer of 1976. A third smock mill stood south of the New Cut and seaward of the ruins of the chapel. Built by the millwright Collins of Melton, it was blown down in the 1920s and a Titt windpump was erected on the site to drive the scoopwheel. This windpump had sails 4.9 metres (16 ft) diameter. Another Titt windpump, with sails 7.6 metres (25 ft) diameter stood 1.6 km (a mile) south of this. Both Titt windpumps were standing in 1938.

The levels were re-flooded during World War II to defend against invasion along the East Anglian coast. Military defences were built at Minsmere and neighbouring Dunwich, including pillboxes, anti-aircraft defences, anti-tank blocks and barbed wire defence lines. The Army also used much of the heathland for military manoeuvres, including preparations for the invasion of continental Europe.

Before the war, the Ogilvie family had owned and managed the area as farmland and as a shooting estate, planting many deciduous trees as part of their hunting management plan. After the war, they decided to leave the marshes undrained, realising their ornithological value.

The RSPB had been considering the Minsmere site, at that time about 600 hectares (1,500 acres) in extent, as a potential reserve from the late 1930s, and a management agreement was signed in 1947. The appointment of Bert Axell as warden in 1959 led to major changes in reserve management, which were in due course also adopted elsewhere. He realised that ecological succession would eventually lead to the loss of important habitats, such as bare ground on the heaths or open water in the reed beds, unless natural plant colonisation was actively prevented. He created the "scrape", an area with shallow water, islands and bare mud, by lowering land levels and managing the water level with new sluices. A circular path led around the scrape, giving access to hides on each of the four sides. In 1977, two years after Axell's retirement, the RSPB purchased the reserve outright.

The Great Storm of 1987 destroyed 3,000 trees in one night. Many areas were reforested, but it was noticed that other badly affected woodlands nearby were colonised by woodlarks, so some recently acquired arable land was acidified and converted to heathland to encourage open-ground species. Minsmere is one of a small number of UK sites at which bitterns breed. In 1979, nine booming males were counted but the population at Minsmere has varied over time, reaching a low of only one booming male in 1991. During the 1990s the existing reed beds were managed specifically for bitterns; when grazing marshes known as the North and South Levels were purchased, the North Levels were converted to reed bed and the South Levels to wet grassland. The Minsmere reserve covers about 1,000 hectares (2,500 acres) of reed bed, open water, lowland heath, grassland, scrub, woodland, dune and shingle vegetation. The nature reserve, its habitats and wildlife, are protected under UK law as part of Minsmere–Walberswick Heaths and Marshes, which is a Special Protection Area, a Ramsar Site, a Special Area of Conservation and a Site of Special Scientific Interest. The site is also included in the areas covered by the Suffolk Coast and Heaths Area of Outstanding Natural Beauty (AONB)and the Suffolk Heritage Coast.

The Sizewell nuclear site consists of two nuclear power stations, one of which is still operational, located near the small fishing village of Sizewell in Suffolk, England. Sizewell A, with two Magnox reactors, is now in the process of being decommissioned. Sizewell B has a single pressurised water reactor (PWR) and is the UK's newest nuclear power station. A third power station, to consist of twin EPR reactors, is planned to be built as Sizewell C.

Sizewell B is the UK's only commercial pressurised water reactor (PWR) power station. Its single reactor was built and commissioned between 1987 and 1995, and first synchronised with the national grid on 14 February 1995. The main civil engineering contractor was John Laing. The power station is operated by EDF Energy. The architectural design was carried out by Yorke Rosenberg Mardall. EDF's strategic target is for 20 year life extension for Sizewell B PWR, beyond the current accounting closure date of 2035.This would mean the plant remaining in operation until 2055. As of 2022, the power station is still planned to close in 2035.

The 'nuclear island' at Sizewell B is based on a Westinghouse '4-loop' plant known as SNUPPS (Standard Nuclear Unit Power Plant System) initially designed in the 1970s and used at Wolf Creek and Callaway but with additional redundancy and diversity in the safety systems, and other modifications such as the addition of a passive Emergency Boration System. The containment design was not based on SNUPPS however, but was designed by NNC (National Nuclear Corporation – bought by Amec Foster Wheeler in 2005) in conjunction with Bechtel.

The Wolf Creek and Callaway plants each have single half speed, 1,800 RPM (60 Hz), steam turbine-alternator sets which use the steam produced from the heat generated in the reactor to produce about 1,200 MW of electricity at the US grid frequency of 60 Hz. Such large turbo-alternator sets were not available in the UK at the time Sizewell B was designed. So that orders could be given to UK manufacturers, and to avoid project risk in dealing with what were at the time newly designed very large turbo-alternator sets, Sizewell B uses two full-speed, 3,000 RPM (50 Hz), nominal 660 MW turbo-alternator sets similar to those used at the AGR power stations Hinkley Point B, Heysham 1, Hartlepool and Torness, and at some fossil-fuel power stations elsewhere, but adapted to cope with the wetter steam conditions produced by the PWR steam supply system. PWR steam supply systems produce saturated steam at lower temperature and pressure than the dry superheated steam produced by AGR reactors or fossil-fuel power stations, and the high- and intermediate-pressure stages of the steam turbines have to be designed cope with this[15] Sizewell B can run at half power using one turbo-alternator. A distinctive white hemisphere envelopes the outer shell of the twin-walled containment building that protects the pressurised water reactor and its steam generators.

First announced in 1969 as an advanced gas-cooled reactor (AGR) based power station, and then in 1974 as a steam-generating heavy water reactor (SGHWR), Sizewell B was eventually announced as a PWR power station in 1980.[21] The initial design submissions to the CEGB and NII were based on the design of the Trojan plant at Portland, Oregon.Designed by Westinghouse, construction of Trojan began in 1970 and was completed in 1975. Westinghouse continued to develop the design they had used for the Trojan plant into the SNUPPS design, built first at Callaway, and SNUPPS was adopted as the basis for the design approved by the CEGB in October 1981.

Before construction commenced, the design of Sizewell B was subjected to a detailed safety review by the Nuclear Installations Inspectorate (NII), and a lengthy public inquiry. The Pre-Construction Safety Case was submitted to the NII in August 1981. The public inquiry was held between 1982 and 1985, and took over 16 million words of evidence, a record at the time. The chairman of the inquiry, Sir Frank Layfield, reported in early 1987 that, subject to a satisfactory safety case, there were no substantive reasons why the project should not proceed. The Nuclear Installations Inspectorate accepted the Pre-Construction Safety Case and issued a licence to proceed with construction in August 1987.

Sizewell B was calculated to be economically viable at a 5% discount rate and was approved financially on that basis. The project cost was revised upwards three times to 135% of the original cost, providing a cost-performance of £2,250/kW (2000 prices) not including first of a kind costs and £3,000/kW including them. A post-startup evaluation estimated generating cost were about 6p/kWh (2000 prices, which is equivalent to £103/MWh in 2020), excluding first-of-kind costs but using an 8% discount rate for the cost of capital, much higher than the expected cost in 1995 of 3.5p/kWh (2000 prices, equivalent to £60/MWh in 2020).

The original rating was for a thermal power of 3,444 MW and gross electrical output of 1,250 MW, which after house load of 62 MW gave a net output to the grid of 1,188 MWe, equivalent to 8.7 TWh (31 PJ) in the year of 2005. It was uprated by 1% in 2013 with a thermal power of 3,479 MW and an electrical output of 1,195 MWe,[11] though this is dependent on seawater temperature.

As with many other PWRs, Sizewell B operates on an 18-month operating cycle, i.e. at or near 100% output continuously for around 18 months, followed by a month's shutdown for maintenance and refuelling. Sizewell B was designed for a commercial life of 40 years (i.e. to around 2035) but similar stations elsewhere have been granted extensions to 60 years.

On 27 May 2008, Sizewell B had an unplanned shutdown, cutting off its supply to the National Grid. A British Energy spokesman said that the fault involved conventional equipment at the plant rather than any part of the nuclear reactor. On 17 March 2010, Sizewell B was taken offline for an extended period because of high moisture levels in the containment building due to a pressuriser electrical heater fault, requiring difficult repairs. On 2 July 2010, just before 21:00, while still offline, a minor fire broke out on the second floor of the building housing the charcoal adsorber at Sizewell B. Numerous emergency services were called to the scene and the fire was brought under control by 3:30 the following day when the charcoal adsorber was flooded. On 2 March 2012, Sizewell B had an unplanned shutdown due to an electrical fault. One and a half weeks later it was restarted at half capacity. As of June 2012, conditions improved and Sizewell B continued under carefully controlled operation.

In 2013, a new remote Emergency Response Centre was inaugurated near the power station, following recommendations made after the Fukushima Daiichi nuclear disaster. The centre provides remote controls and a back-up plant. In January 2014, the building of a dry spent nuclear fuel store began. The existing spent fuel pool, which stores spent fuel under water, was expected to reach full capacity in 2015. In April 2016, the building was inaugurated. This will enable spent nuclear fuel produced from autumn 2016 until at least 2035 to be stored until a deep geological repository is available. In March 2017, the first cask containing spent nuclear fuel was installed. In 2021, Sizewell B had an extended outage for maintenance and safety related issues. The Times reported that excessive wear on some stainless steel "thermal sleeves" in the control rod mechanisms had been discovered. The maintenance period was extended to over four months to evaluate the cause and extent of the wear to decide how many to replace.