UPDATE 1-French watchdog investigates potential nuclear safety fraud

(Adds detail on falsification of identities)

PARIS, May 13 (Reuters) - French nuclear regulator ASN said it had launched an investigation into elements of fraud and falsification regarding nuclear safety, after receiving several warnings from whistleblowers.

Last November, the ASN launched a website where the public can highlight irregularities regarding nuclear safety, which followed a 2016 scandal over falsified manufacturing documents at former nuclear reactor maker Areva and a string of problems with weldings and components at EDF nuclear reactors. Areva is now part of state-owned utility EDF and renamed Framatome.

The ASN said in a statement on Monday that since then it had received 22 warnings and had launched an investigation into a small number of these as they had the characteristics of potential fraud cases.

It also said it had already referred four cases to the criminal court. It declined to give more details about them.

The regulator did not identify any companies involved in the investigation.

EDF - which operates the 58 nuclear reactors that generate some three quarters of French electricity - said it could not immediately comment on ASN’s statement.

The ASN said that initial investigations had revealed several problems, such as the use of inappropriate materials, certain activities, such as welding, carried out by people who did not have the necessary skills, and safety controls that were either missing or executed by internal staff only.

The regulator said this could have a number of implications, such as modification of test results, falsification of the identity of staff having and the non-execution of certain operations such as the replacement of components. (Reporting by Geert De Clercq; Editing by Sudip Kar-Gupta and Jane Merriman)