PROCEDURE No.: VNSPL/LT/NPP/2014/001Date :18-08-2014

VIBRANT NDT SERVICES PRIVATE LIMITED

PROCEDURE FOR

HELIUM LEAK TESTING OF CONDENSER NEGATIVE PRESSURE PARTSPREPARED BYREVIEWED BYAPPROVED BY

K.SATHISH

ASNT LEVEL IIS.RAJA

ASNT LEVEL IIP.JAYAKANDAN

ASNT LEVEL II

1. SCOPE

This procedure is applicable for Helium Leak Testing of Condenser Negative Pressure Parts using detector probe method.

2. REFERENCE DOCUMENTS

ASME SEC. V Article 10 appendix IV

3. EQUIPMENT

3.1. The equipment shall be capable of detecting the leaks by sniffer method.3.2. The following equipment will be used for Helium Leak testing ALCATEL ASM142.

4. QUALIFICATION OF PERSONNEL

The personnel carrying out of the Leak Testing examination and evaluation under this procedure shall be qualified as per ASNT LT Level II.

5. CALIBRATION LEAK STANDARD

The calibration leak standard shall be Permeation type -

Calibration leak standard having known leak rate of 1.4 x 10-7 Std cc/sec is used to calibrate the Helium Mass spectrometer Leak detector (MSLD) such that theMSLD establishesthe same Leak rate value of 1.4 x 10-7 std cc/sec shown in calibration leak standard.

6. INSTRUMENT CALIBRATION

6.1 WARM UP

The instrument shall be turned on and allowed for a warm up period of 3 minutes prior to calibrate with the calibrated leak standard.

6.2 CALIBRATIONThe instrument shall be calibrated using the calibration leak standard and the equipment has a sensitivity of at least 1x 10-9 Std cc/sec

7.0 SYSTEM CALIBRATION

7.3.1. Scanning Rate

The probe shall be kept within 3 mm of the test surface during Testing.

8.0 TESTING

8.1 The Most Sensitive and Sophisticated Alcatel ASM 142 Helium leak detector

Connected to the Systems, Air Removal System detects even low traces of helium.8.2 Helium is applied to the various components within the vacuum boundary of a turbine / condenser system. Incase of a leak, the injected helium enters the steam side of the condenser and is removed by the system, the same will be correspondingly detected by the leak detector connected to the air removal system.8.3This same procedure will be adapted to all the negative pressure parts individuallyWhile the unit is in service. All the leaky spots identified will be tagged for further repairing action at your end.8.4Helium inspection being Qualitative inspection, only samples of the off gases from the ejector is analyzed by the mass spectrometer. The entire off gases can be monitored, however the cost and time involved in the inspection becomes high.Hence the leak rate observed is categorized based on the experience of the inspection Engineer.8.5Leak indication are specified in mbar.l/s.Based on the leak rate the leaks can be categorized as small,medium,large,very large and severe.8.6Each leak is recorded with location, analyzed value, and size. 9. ACCEPTANCE NORMS

Any leak rate in excess of 1.0x 10-5 Std cc/sec shall be marked and the area shall be rectified and retested.

10. REPORT

The report shall include the following details:

1. Date and Examination

2. Report Number

3. Operator ID and Qualification

4. Calibration Standard and Serial Number

5. Mode of Operation(Sniffer)

6. Signatures of Qualified test/inspection personnel & all parties who witness the test

7. Photographs of leak Points

8. Result