* New doctrine chief says no deal with traditionalists
* SSPX rebels refused to accept Vatican Council reforms
* Pope, aides to decide next step in long tussle with SSPX
By Tom Heneghan, Religion Editor
PARIS, Oct 5 (Reuters)- The Vatican plans no more talks with rebel Catholic traditionalists who insist the Church must revoke modernising reforms launched five decades ago, Pope Benedict's main doctrinal official has told a German interviewer.
Archbishop Gerhard Mueller, who took up his post as head of the powerful Congregation for the Doctrine of the Faith (CDF) in July, said in an interview to be broadcast on Saturday that the Church could not negotiate away the fundamentals of its faith.
His comments to North German Radio (NDR) were the first from the Vatican on deadlocked talks meant to reintegrate the Society of Saint Pius X (SSPX) into the Church after a 21-year schism over its implacable opposition to 1960s reforms.
In recent weeks, SSPX leaders have indicated a two-year series of talks with the Vatican had hit an impasse because Rome's insistence that they accept reforms of the 1962-1965 Second Vatican Council was a deal breaker for them.
"We cannot give away the Catholic faith in negotiations," Mueller said according to a pre-broadcast report by NDR.
"There will be no compromises here," he said. "I think there now will be no new discussions."
The German-born Pope Benedict and the CDF, which the pontiff led for over two decades under Pope John Paul, will now have to decide what to do next with the SSPX, Mueller said.
The Swiss-based SSPX broke away from Rome in 1988 in protest against the 1960s Council reforms that replaced Latin with local languages at Mass, forged reconciliation with Jews and admitted that other religions may also offer a path to salvation.
NO BREAK WITH CATHOLIC TRADITION
Since becoming pope in 2005, Benedict has met the head of the SSPX, promoted the old Latin Mass it champions and lifted excommunications imposed on the group's four bishops when they accepted ordination against Vatican orders.
Benedict's concessions to the SSPX caused a storm of protest from Catholics, Jews and Germans in 2009 when it emerged that one of the bishops whose excommunication was lifted was a notorious Holocaust denier and the Vatican did not even know it.
Lifting the excommunications meant the four bishops were once again full members of the 1.2-billion member Church, but they and the SSPX - which claims to have 500 priests and a million followers - had no official position or role within it.
In 2010, the Vatican launched closed-door theological discussions with the rebels aimed at an agreement that would make the SSPX a "personal prelature" or autonomous institution in the Church similar to the conservative group Opus Dei.
Benedict insisted they must declare the Vatican Council and Church doctrine since then as valid Catholic teaching.
Denying this has been a core SSPX principle from the start and SSPX leaders have said their discussions with the Vatican aimed to "convert Rome" to return to the pre-Council Church.
Mueller, who crossed swords with SSPX traditionalists while he was archbishop of Regensburg in Germany before going to Rome, rejected the group's central argument that the Council broke with a Church's 2,000-year traditions.
"The Second Vatican Council does not contradict the Church's overall tradition, but only some false interpretations of the Catholic faith," he said. (Editing by Robin Pomeroy)