Site Incident Report (Sir)

SITE INCIDENT REPORT (SIR) SIR P3459

To Anil Kumar Date 12th November 2012

From Gerry McGuinness Project No. 06361, 06368 Unit No. P1, P2, P3

UTE PORTO DO PECEM SIR Number P3459 Item of Plant:

Location on Site: Steam & Water system

Reference Documents/Drawings: 06361/YLTL/AI/30000/9365 Rev G

Description of Incident

During routine checks of the above valves on Boiler 2, it was found that the actuator on valve 21SGJ30AA151 would not drive the valve. Investigation showed that the tack welds and grub screws used to transmit the drive had failed and that there was no key fitted due to the drive bush adaptor having been manufactured with its external keyway in the wrong position. All valves (24 off) have since been checked on Boiler 1, 2 & 3 5 other valves also had cracked tack welds and/or broken grub screws. A total of 19 valves were found to employ this method of transmitting drive and of the 5 that do use drive keys, 3 have also employed tack welds and/or grub screws. A matrix illustrating these combinations is attached.

This method of using tack welds and grub screws for transmitting drive is unsatisfactory. It is clear that the drive bush adaptors have been manufactured incorrectly with the external keyway in line with one of the internal keyways. See attached photos. Both of these features represent poor engineering practice. These drive bush adaptors should have been manufactured with the external keyway at right angles to the internal keyways.

Proposed Solution Due to urgency, 24 new drive adaptors will be manufactured locally and fitted. All costs to be backcharged to AIL.

Responsibility for the cost/Incident: Audco India Ltd Authorized By (DBEL): Date

SIR Distribution: Client DBEL

SITE USE ONLY Date Closed-out: Signature (Client)

SIR P3459 Page 1 of 4 Inerting Valve Maintenance Inspection

Unit One

Valve no. External Grub Tack Welded Keyway Screws 11SGJ10AA151 Not used none none 11SGJ10AA155 Not used used yes 11SGJ20AA151 Not used used yes 11SGJ20AA155 Yes none yes 11SGJ30AA155 Not used used yes 11SGJ30AA151 Yes none yes 11SGJ40AA155 Not used Used & broken yes 11SGJ40AA151 Yes none none

Unit Two

Valve no. External Grub Tack Welded Keyway Screws 21SGJ10AA151 Not used used no 21SGJ10AA155 Not used used yes 21SGJ20AA151 Not used used yes 21SGJ20AA155 Not used used Yes & cracked 21SGJ30AA155 Not used used Yes & cracked 21SGJ30AA151 yes Used & broken yes 21SGJ40AA155 Not used Used yes 21SGJ40AA151 yes none no

Unit Three

Valve no. External Grub Tack Welded Keyway Screws 31SGJ10AA151 Not used yes Yes & cracked 31SGJ10AA155 Not used yes yes 31SGJ20AA151 Not used yes Yes cracked 31SGJ20AA155 Not used yes yes 31SGJ30AA155 Not used yes yes 31SGJ30AA151 Not used yes Yes & cracked 31SGJ40AA155 Not used yes no 31SGJ40AA151 Not used yes yes

SIR P3459 Page 2 of 4 Photo 1 – drive adaptor on 21SGJ30AA151 showing keyway in wrong location, missing key, two tack welds (one cracked) and two grub screws

SIR P3459 Page 3 of 4 Photo 2 – 21SGJ30AA151 whose actuator would not drive valve – both tack welds broken and grub screws rolled out leaving scores

Photo 3 - close up of drive bush – note wall thinness at double keyway SIR P3459 Page 4 of 4