Hunterston Nuclear Power Station (Hansard, 26 October 1987)

§ Mr. Lang

The nuclear installations inspectorate's site incident register at Hunterston nuclear power station records a total of 50 incidents between 1 January and 14 October 1987. The date and nature of the incidents are shown in the tables below. The circumstances under which the nuclear site emergency alert alarm is required to be sounded are specified in the Hunterston emergency plan; in none of the incidents did these conditions arise.

Hunterston 'A' Power Station
Summary of site incident register entries:
1 January 1987 to 14 October 1987
Date	Nature of incident
17 January 1987	Failure of charge machine vessel safety valve flange led to minor release of CO₂, which was detected and alarmed by the Reactor 1 vault CO₂ detection system.
28 January 1987	A passing valve in the CO₂ plant caused a rise in the reactor pressure of 6.4 psi in 35 minutes.
10 April 1987	Contamination detected on Reactor 2 pipebridge. Maximum activity KM) counts per second (cps).

59W

Date	Nature of incident
27 April 1987	Contamination detected at entry to Solid Active Waste Building. Maximum activity 400 cps.
8 May 1987	Contamination detected on charge machine rail near Solid Active Waste Building. Maximum activity 600 cps.
20 May 1987	Contamination detected on Health Physics instrument used at Reactor 2 Separation Room barrier. Maximum activity 300 cps.
9 June 1987	Spread of contaminated dust occurred when emptying Reactor 1 Separating Room cyclone filter. One person contaminated with maximum activity of 100 cps.
9 June 1987	Contamination detected on Health Physics instrument used during Reactor 1 Separating Room cyclone filter change. Maximum activity 50 cps.
14 June 1987	Clothing contamination detected at IPM7 personnel monitor. Maximum activity 25 cps.
16 June 1987	Clothing contamination detected at IPM7 personnel monitor. Maximum activity 10 cps.
23 June 1987	Personnel contamination detected at IPM7 personnel monitor. Maximum activity 300 cps.
23 June 1987	Clothing contamination detected at IPM7 personnel monitor. Maximum activity 425 cps.
24 June 1987	Contamination detected at barrier to Reactor 2 gas dryer. Maximum activity 200 cps.
30 June 1987	Clothing contamination detected at IPM7 personnel monitor. Maximum activity 15 cps.
3 July 1987	Clothing contamination detected at IMP7 personnel monitor. Maximum activity 50 cps.
6 July 1987	Clothing contamination detected. Maximum activity 100 cps.
6 July 1987	Contamination detected on scaffolding below SRU entry manhole. Maximum activity 500 cps.
9 July 1987	Failure of a fuel element in Reactor 1 required a reduction in power whilst preparations were made for its removal.
10 July 1987	Personnel nasal contamination detected. Contamination level of 14.7 Becquerels.
17 July 1987	Clothing contamination detected at IPM7 Personnel Monitor. Maximum activity 1000 cps.
22 July 1987	Contamination detected at barrier of Lightly Active Waste Facility. Maximum activity 200 cps.
22 July 1987	Piece of magnox found on cooling pond roadway. Maximum activity 4000cps.
22 July 1987	Contamination detected on roadway adjacent to 5A gas circulator. Magnox activity 1800 cps.
27 July 1987	Contamination detected at HP drum level of 2B SRU. Maximum activity 350 cps.
27 July 1987	Clothing contamination detected at IPM7 personnel monitor. Maximum activity 200 cps.
10 August 1987	Leakage from tritium bottle during transit.
12 August 1987	Surface contamination found on 2B SRU pipework.
16 August 1987	Failure of rotameter on BCD system.
5 September 1987	Shortage of cooling water, due to an ingress of seaweed into the CW system, led to Reactor 1 being manually tripped.
5 September 1987	Shortage of cooling water, due to an ingress of seaweed into the CW system, led to Reactor 2 being manually tripped.
10 September 1987	Spread of contamination occured when emptying cyclone filter bag.

60W

Hunterston 'B' Power Station
Summary of site incident register entries:
1 January 1987 to 14 October 1987
Date	Nature of incident
13 February 1987	Failure of coupling on CO₂ service supply hose on charge machine.
16 February 1987	Clean CO₂ from a vaporiser was transferred to the deaerator via the domestic steam system because of a leak in the steam heating pipework at the vaporiser and another in the deaerator heating coil.
17 February 1987	Problems in releasing the charge machine grab from a control rod after its removal from the reactor.
9 March 1987	Failure of both IGV drive motors on gas circulator 4A2.
18 March 1987	Broken wire on Reactor 3 channel 3 pulse counter had caused the channel to trip.
5 April 1987	Trip of 4C quadrant on low lubricating oil pressure.
7 April 1987	Fire due to an electrical fault on R3 ESS Short Break Sub-board 3B.
7 April 1987	Trip of 3A quadrant due to board fault in incident of 7 April 1987 above.
8 April 1987	Contamination detected on shock absorber of road transport flask E67A. Maximum activity 30 cps.
10 April 1987	Clean CO₂ leak from joint on No. 6 vaporiser.
17 April 1987	Loss of vacuum due to inadvertent opening of air suction valves on vacuum maintaining unit.
17 April 1987	Problem with the cooling pond skip transporter led to the tilting of a skip.
12 May 1987	Closing of fuel stringer gag instead of opening.
12 May 1987	Small leak of reactor CO₂ from BCD sample valve on channel R3–2060.
11 June 1987	Trip of 4D quadrant on very low lubricating oil levelled to unit trip.
7 August 1987	Trip of unit 3 due to turbine governor problems.
15 September 1987	Reactor 4 gas leakage over a period of 18 minutes due to the partial failure of a joint in the gas treatment plant area. Source of reactor CO₂ leak isolated, and reactor continued operating.
16 September 1987	Small fire in R3 oil bund of 3C quadrant.
3 October 1987	Trip of unit 4 when control rod fell into core.