By Clarence Fernandez

SINGAPORE (Reuters) - Japan's metals and energy sectors were grappling on Monday with power outages and raging fires unleashed by last week's devastating earthquake, but some ports and steel furnaces shut in a protective move reopened.

Japan, the world's third largest consumer of commodities, is battling to avert a nuclear catastrophe in its worst crisis since World War Two after Friday's earthquake, which is feared to have killed more than 10,000 people.

The northeast coast ports of Hachinohe, Sendai, Ishinomaki and Onahama were so severely damaged that they were not expected to return to operation for months. But power outages and fires resulting from the earthquake present an immediate risk.

Top refiner JX Nippon Oil and Energy Corp waited in hopes of extinguishing later on Monday a fire at a 145,000-barrel-per-day refinery in Sendai that it had been unable to fight because of tsunami warnings and refinery staff evacuation.

Another fire, at the 220,000-barrel-per-day Chiba refinery east of Tokyo run by Japan's Cosmo Oil has not yet been put out, a company spokesman said.

Key Japanese steelmakers stopped production at some plants in the face of power cuts imposed to cope with the quake devastation, although analysts say overcapacity elsewhere could limit the impact on steel prices.

JFE Steel Corp, the world's No.5 steelmaker, on Monday halted production at a plant near Tokyo and No.4-ranked Nippon Steel suspended operations at two small plants.

Sumitomo Metal Industries Ltd, Japan's No. 3 steelmaker, said production at its main Kashima plant in Ibaraki prefecture remains suspended.

SHIPPING

The port of Tokyo and other southern harbors were operating normally on Monday, though damage at northern ports was being assessed, industry officials said.

"These ports will need a lot of time until they can be fully restored," Tetsuya Hasegawa, operation manager at Heisei Shipping Agencies in Tokyo, told Reuters.

Japan had temporarily shut its ports on Friday after being hit by the worst earthquake in its recorded history, of magnitude 8.9, and a tsunami that followed.

On Monday, premiums for gold bars in Tokyo jumped to their highest level since February, standing at $1 an ounce versus spot London prices, compared to zero last week after inflation fears were sharpened by the earthquake in Japan, dealers said.

"The Japanese market is a bit tight on gasoline, so there are inflation risks. That's why Tokyo premiums are a bit higher," said a dealer at a bullion trading house in Tokyo.

Japan must act quickly to import more liquefied natural gas (LNG) and low-sulphur fuels to generate power at thermal plants and replace nuclear electricity supplies put out of action by the quake.

Significant power supplies in Japan, which ranks third in terms of oil imports and size of its economy, were crippled by the earthquake, causing the loss of an estimated 9,700 megawatts (MW) of nuclear, about a fifth of capacity, and 10,831 MW of thermal power generation.

Indonesia's state oil and gas firm Pertamina said shipments of liquefied natural gas (LNG) were running normally from its Bontang plant to major importer Japan, while oil and gas watchdog BPMigas said 20 LNG cargoes from Bontang were available for auction.

JX Nippon Oil & Energy Corp, which halted operations at its three refineries in Sendai, Kashima and Negishi after the quake, may start extinguishing a fire at an oil product shipping facility and storage tanks at its Sendai refinery later on Monday, a company spokesman said.

JX resumed oil product shipments from its 270,000 barrels per day Negishi refinery south of Tokyo, the company said, though supply would be limited until the restart of the refinery was completed.

Japan is likely to turn to oil -- mainly low-sulphur fuel oil or low-sulphur crudes such as Indonesia's Duri -- as replacement power-generation fuel in the wake of the earthquake that resulted in the closure of several nuclear plants.

"Right now, it's not clear how much fuel oil they are going to buy, but it is quite certain that they will, and in large volumes. As of now, they have not come out to look for any low-sulphur fuel as yet," said a Singapore-based Japanese trader.

Barclays Capital estimates that replacing the lost power-generation capacity will require the equivalent of 204,000 barrels of oil per day (or about 30,000 tonnes), similar to a Very Large Crude Carrier (VLCC)-load of low-sulphur cargoes every eight days.

International oil prices will fall after the earthquake, but could rebound in a couple of months, said Jiang Jiemin, chairman of Asia's leading oil producer PetroChina, whose joint refinery in Japan was not affected.

Asia's biggest thermal coal exporter, PT Bumi Resources, sees coal prices and demand going up in the medium term after the earthquake, company director Dileep Srivastava said, with the main catalysts being Japan's need to rebuild and the substitution of coal power for nuclear.

Japan is the top buyer of Indonesian coal, accounting for 21 percent of Bumi's sales in 2011.

STEEL FIRMS STOP PRODUCTION ON OUTAGES

Steel prices in Asia are likely to rise after the earthquake and tsunami hit Japan's steel mills, constraining exports from the world's second largest producer, analysts say.

JFE said shipments from its 10 million tonnes per year Higashi Nihon plant near Tokyo had been virtually halted by a power outage.[ID:nTFD006676] JFE, which has total production capacity of about 32 million tonnes, resumed operations on Sunday of two blast furnaces at its Higashi Nihon plant, one of its two mainstay plants, which were idled after Friday's quake and tsunami.

(Reporting by bureaux in Tokyo, Beijing, Jakarta, Sydney and Singapore; Editing by Himani Sarkar)