Troubled energy group British Energy has called on the government to increase its current £200m loan ($340m).
British Energy underwent financial restructuring in October
The group confirmed it was asking for more cash, but refused say how much.
It is thought to be asking for an extra £100m. In September, the firm said it had already used up £106m of its current loan.
The firm blamed the unexpected closure of Sizewell B and Heysham 1 nuclear power stations for its problems - saying the action would hit its income.
Just two weeks ago, British Energy warned that the financial impact of the closures would be much more than the original estimates of £20m-30m.
Experts predict the outages could cost as much as £50m.
At Heysham 1, in Lancashire, both reactors were shut down on 28 October following the failure of a sea water cooling pipe.
The site is now set to remain offline until the middle of December - three weeks longer than originally expected.
Meanwhile, when Sizewell B in Suffolk was shut down for routine maintenance, a suspected "anomaly" was found.
More tests at the plant revealed there was no anomaly, but it meant the site was closed for two weeks longer than the normal shutdown for maintenance.
British Energy's loan, which was needed to enable the company to see out a life-saving financial restructuring, dates back to September of last year.
The company was kept afloat by a £650m government loan, which was subsequently replaced with the £200m facility in March.
British Energy said: "The company can confirm that it has approached the Secretary of State for an increase in the government facility and that discussions are continuing, but no agreement has yet been reached."