MSE CONTROLLED DOCUMENT. Radiological HSE Precautions for Pigging Operations

Transcription

1 MSE CONTROLLED DOCUMENT Radiological HSE Precautions for Pigging Operations Document No: Supersedes Revision no: 1 1/10/2004 Custodian: MSE Revision no: 1 1/10/2006 Filename: NORMMGT. DOC Administered by: Verified: Verified: Approved: Approved: MSE/32 RPA OSD/OND MD 1/10/2004 Reason for revision: This document contains proprietary information and is intended for use by PDO and Contractor staff only. The contents of this controlled document shall not be changed without formal approval of the document custodian.

2 Contents 1. Introduction Objective Scope Responsibilities Permit Applicant Responsible Supervisor Area Authority Permit Holder (Work Supervisor) Contractor RPT (Radiation Protection Technician) Performance PPE and auxiliaries Safety measures and work instruction General Pigging operations... 3 APPENDICES Appendix 1: Glossary of Abbreviations... 5 Page 1

3 1. Introduction Routine pigging is carried out to prevent the build up of sludge and scale in pipelines to improve flow. Pipelines may contain NORM contaminated scale and debris and therefore radiological controls are required for pigging operations. NORM contamination of the receiver and pig has occurred previously e.g. 8" Oil Ramlat Rawl to Saih Rawl Receiver. Note: NORM can be found in both oil and gas pipeline systems and monitoring for NORM is required when pigging both systems. The types of radionuclides can vary as natural gas may contain Radon 222 which decays to Pb-210. It may also contain Ra-226 if scale from reservoir water occurs in the system. Both radionuclides require monitoring using Mini Monitors but with different probes. When monitoring gas systems, the Mini 900 with EP15 probe is needed, whilst oil/water lines requires use of the Mini 900 with 44A probe. A key requirement is to use the PtW and conduct a NORM Radiological Survey. The results of the NORM Survey must be recorded on the NORM Radiological Survey Form (Appendix 1 of SP 1170) and attached to the PtW. Pigging contractors must implement this system and employ trained personal, use the PDO approved NORM contamination Meter (Mini 900 with 44A probe) and utilise the appropriate PPE if NORM is found > 5cps above background. NORM contaminated debris > 5 cps above background may exceed the limit for unconditional free release (1 Bq/g for Ra-226) and must be analysed for activity (Bq/g) by SQU. NORM contaminated debris exceeding 1 Bq/g for Ra-226 cannot go to the sludge farm and must be contained in a sealed drum, labelled and taken to the NORM storage yard in Bahja for storage. If the pig records > 5 cps above background, it must be wrapped in thick polyethylene plastic or stored in a sealed drum until cleaned. A procedure for cleaning contaminated pigs has not been developed by the contractor or PDO. Ideally they will high pressure cleaned in a controlled box and the debris collected for proper disposal. 1.1 Objective To define the radiological HSE precautions for pigging operations. 1.2 Scope This procedure shall apply to all PDO and contractor personnel involved in pigging operations 2. Responsibilities 2.1 Permit Applicant The Permit Applicant is responsible for requesting the NORM Survey be conducted by a trained RPT when retrieving the pig and the NORM Survey Record is attached to the PTW. 2.2 Responsible Supervisor The Responsible Supervisor is responsible for verifying that the Permit Applicant has requested a NORM Radiological Survey for all pigging activities. The Responsible Supervisor shall ensure that Contractor has the approved meter(s) to conduct the NORM Radiological Survey, the appropriate personal protective equipment and sealable drums for collecting NORM contaminated sludge, debris or scale. Page 2

4 2.3 Area Authority The Area Authority is responsible for verifying that the Contractor has an approved RPT to undertake the NORM radiological Survey. The Area Authority shall verify that the RPT attaches the NORM Radiological Survey to the PTW and the Contractor complies with the controls outlined in the Survey and these NORM Guidelines. 2.4 Permit Holder (Work Supervisor) The Permit Holder is (usually the Permit Applicant as defined on the Work Permit) is responsible for the implementation of this procedure. Usually the Permit Holder will be the Work Supervisor and will be the trained RPT who undertakes the NORM Radiological Survey and outlines the system of work. 2.5 Contractor RPT (Radiation Protection Technician) The Pigging Contractor is responsible for ensuring that an appropriately trained RPT forms part of the pigging crew and is able to undertake radiation and contamination measurements and can advise on radiological controls. The controls shall be included in the NORM Radiological Survey attached to the PTW. 3. Performance 3.1 PPE and auxiliaries Prior to commencing work, the Permit Holder shall ensure the availability of PPE, auxiliaries and NORM meter(s) as per MSE Safety measures and work instruction General All pipelines/receivers shall be treated as NORM contaminated until RPT measurements prove otherwise. Supervision by the Permit Holder or his nominated deputy is mandatory. All personnel shall attend a NORM awareness course and be familiar with the hazards and safeguards involved with NORM jobs. A competent NORM Meter user (RPT) shall be available to measure equipment, record results and to provide guidance on controls and recovery measures Pigging operations If previously concreted the pig trap area must be cleared of any debris or sand before the operations start. RPT shall conduct background measurements and record them on the NORM Survey Form found in Appendix A of SP 1170 Version 3.0. Generally background with the Mini 900/44A probe is around 3-5 cps and with the Mini 900/EP15 Probe around 0.5 cps. RPT shall conduct exterior NORM measurements at the pig launcher or receiver door Page 3

5 prior to opening. Measurements of gamma radiation > 5 cps above background externally suggests higher levels inside. RPT to record results in the NORM Radiological Survey Form. Upon opening the pig trap, care must be taken to minimise the amount of silt and sludge falling into the sump beneath it. Plastic may be used to contain the sludge if convenient. As soon as the trap is opened, the debris in the trap must be monitored by the RPT. If NORM is detected > 5 cps abg, all workers in the Supervised Area must don the appropriate PPE. ( Disposable overalls, gloves, P3 Respirator) If active minimise persons in the Supervised Area. Sufficient approved drums to hold waste are needed and a water tanker may be useful on site. RPT to specify the Supervised Area, as per MSE.05. If active for NORM carefully flush the pig, launcher and receiver over a sealable liquid waste drum to remove loose debris. Remove any remaining deposits in the pig launcher or receiver using tools and place in the solid waste drum. Re-monitor the pig with the NORM contamination meter and if still positive, rap it in plastic or place in a sealable drum for transport to the workshop. All persons shall be checked for contamination on exit from the Supervised Area. If contamination is found, use a wet towel to wipe of any debris and re-monitor the person. Wring the towel with water into the drum until clean of NORM. Equipment used inside the Supervised Area shall be checked for contamination with the NORM meters prior to removal. Any equipment which can not be cleaned with water shall be bagged, sealed and marked externally as NORM contaminated with activity levels and logged as per MSE.06. The RPT shall now check the surrounds of the pigging area to ensure contamination of the ground has not occurred. Where readings exceed 5 cps above background the soil area shall be collected and placed into the sealable drum until background is reached. Any further waste generated shall be checked for NORM contamination and if activity is found, placed in drums. The contractor shall develop procedures for cleaning a contaminated pig which does not generate airborne particles. This may involve soaking the pig in a chemical/surfactant to remove oily deposits which can then be added to the solid NORM waste drums. Alternatively the pig can be placed into a metal 44 gallon drum with holes in the bottom. The drum can be placed over a grated sump. The pig is then carefully washed inside the drum using a high pressure gurney. The water and debris from the pig passes through the holes and is allowed to settle in the sump where it can dry and be monitored at a later stage. If it reads positive for NORM it can be collected and placed in a sealable drum for disposal at the Bahja NORM storage facility. Once a drum is full it can be sent to Bahja for storage and eventual disposal. NORM Contaminated waste shall be transported to the Bahja NORM yard as per MSE.08. Page 4

6 Glossary of Abbreviations Appendix 1 PPE RPT PtW Personal Protective Equipment Radiation Protection Technician Permit to Work Page 5