UK GAS-Prompt prices rise on unplanned outage, higher exports

* Bacton Seal outage cuts supply by 11 mcm/d

* Day-ahead prices recover after 10 pct fall on Monday

LONDON, Aug 16 (Reuters) - British prompt gas prices rose on Tuesday morning as an unplanned domestic outage and an increase in exports to Belgium helped prices recover from Monday's rout.

Gas for immediate delivery was up 1.5 pence, or 5.4 percent, at 29.50 pence per therm at 0849 GMT.

Gas for day-ahead delivery was up 0.65 pence to 29.85 p/therm.

With supply flows at 150.7 million cubic metres (mcm) and demand expected to be 154.3 mcm/day, Britain's gas system was 3.6 mcm undersupplied, National Grid (LSE: NG.L - news) data showed.

"IUK (Interconnector UK) exports shooting up and Bacton Seal in an unplanned outage are all price upside factors, especially after yesterday's freefall," said gas analysts at Thomson Reuters in a daily research note.

Prompt prices fell more than 10 percent on Monday as high imports from Norway combined with low exports to Belgium to leave the British gas market heavily over-supplied.

Gas exports from Britain to Belgium through IUK were nominated at 33 mcm/day, up from around 12 mcm the previous day, Thomson Reuters (Dusseldorf: TOC.DU - news) data showed.

Meanwhile domestic supply was cut by 11 mcm/day due to an unplanned outage at Total E&P's Bacton Seal gas terminal.

The outage began on Monday and was not expected to end before Wednesday, the operator said in a market update.

Gas prices further along the curve also edged higher, with the Winter 2016 gas contract up 0.20 pence at 42.50 p/therm.

In the Netherlands, the day-ahead price at the TTF hub was up 0.3 euro at 11.45 euros per megawatt-hour.

In Europe's carbon market, the front-year EU allowance price was up 0.02 euro at 4.83 euros per tonne. (Reporting by Susanna Twidale; Editing by Adrian Croft)