* Senate approves second of two main clauses
* Train and air traffic disruption expected
* Oil port strike in southern France enters 15th day (Adds Senate vote)
By Helen Massy-Beresford
PARIS, Oct 11 (Reuters) - French unions are preparing for more protest strikes this week over planned pension reforms, a major point of which was rushed through the Senate on Monday.
The Senate voted 174 to 159 in favour of raising the age at which workers can retire with a full pension to 67 from 65.
The measure is one of the two main planks of President Nicolas Sarkozy's reform package -- the Senate agreed last Friday to raise the minimum retirement age to 62 from 60 -- and means the unpopular bill is closer to becoming law.
Transport workers plan to disrupt train and air travel on Tuesday and street protests are expected in a fresh wave of unrest over Sarkozy's push to make people work longer to ease the deficit in the pension system.
Limited power cuts targeting public buildings are also expected as utility workers join the strike movement, France's CGT union said in a statement, calling the cuts "symbolic".
Secondary school pupils were set to join workers in Tuesday's marches, union leaders said. Students at some universities were also expected to demonstrate.
Across Europe, austerity measures to trim budget deficits have sparked public anger and protests.
Sarkozy's flagship pension bill is turning into one of the biggest battles of his presidency, pitting him against powerful unions who crushed a previous attempt to reform pensions in 1995, and weighing on his already low popularity ratings.
The reform is aimed at safeguarding France's cherished AAA credit rating, which enables it to borrow at low market rates.
The bill has already been approved by the lower house of parliament and is now making its way piecemeal through the upper house. Parliamentary approval of the entire reform is expected by late October, after which the bill would go to France's constitutional council for a final rubber stamp.
Sarkozy made a small concession in the pension bill last week to middle-aged women who had given up work to raise children, but his office says he has no intention of backing down on the essentials and is betting on protests waning.
TRAINS AND PLANES
Paris's RATP urban transport network said the metro would be disrupted and some suburban trains would be more severely hit by Tuesday's strikes.
National rail operator SNCF expected around one in three high-speed TGV trains to run. Around eight out of 10 Thalys trains to destinations including Brussels were expected to run, while Eurostar services were expected to operate as usual.
Flights would be cut by 50 percent at Paris's Orly airport on Tuesday and by 30 percent at CDG-Roissy and Beauvais airports, the DGAC civil aviation authority said on Monday.
Port strikes in southern France continued on Monday, as workers denounced port reforms as well as the pension bill.
Workers at France's top oil port of Fos-Lavera pushed a strike into its 15th day, forcing a partial shutdown of a major refinery and calling for strikes to be extended at all French ports on Oct. 12.
Some transport and energy unions have made more radical calls for rolling strikes from Tuesday, and the big trade unions have called a further day of protest on Oct. 16.
"This is one of the last chances to make the government retreat," Francois Chereque, head of the CFDT, one of France's main unions, told French iTele on Sunday.
A survey of just over 1,000 people published in Le Parisien newspaper on Monday showed 61 percent were in favour of a "continuous and lasting" strike, while 69 percent supported the planned strikes on Tuesday. (Additional reporting by Gerard Bon and Elizabeth Pineau; Editing by Peter Graff)