MSE CONTROLLED DOCUMENT Radiological HS&E Precautions for NORM Document No: Supersedes Revision no: 1 Date:1/10/2004 Custodian: MSE/32 Revision no: 1 Date: 1/10/2006 Filename: NORMMGT. DOC Administered by: Verified: Date: Verified: Date: Approved: Date: Approved: Date: MSE/32 RPA OSD/OND UWD/GD Date: 1/10/2004 Date: Date: Date: 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.
Contents Radiological HS&E Precautions for NORM 1. Introduction... 2 1.1 Objective... 2 1.2 Scope... 2 2. Responsibilities... 3 2.1 Permit Applicant... 3 2.2 Permit Holder (Work Supervisor)... 3 2.3 Responsible Supervisor... 3 2.4 Area Authority... 3 2.5 Contractor... 3 3. Performance... 4 3.1 PPE and auxiliaries... 4 3.2 Health & Safety Measures and Work Instruction... 4 3.2.1 General... 4 3.2.2 Entering NORM Contaminated Vessels/Tanks... 4 3.2.3 Cleaning NORM Contaminated Vessels / Tanks... 5 APPENDICES Appendix 1: Glossary of Abbreviations... 7 Page 1
1. Introduction Cleaning operations of tanks, vessel and separator are periodically required to remove deposited sludge, sand, clay and scales. Past experience has demonstrated that the level of sludge in the tanks can vary from several centimetres in height up to two (2) meters. Prior planning by Maintenance Services to determine if tanks scheduled for cleaning/inspection are NORM contaminated is essential. These procedures shall only apply to tanks, vessels or separators when monitored externally and internally with the Mini 900 with 44A probe exceed 5 cps above background. Note background is typically 3-6 cps in the PDO Assets. Tanks are assumed to contain NORM sludge/silts until proven otherwise by monitoring and analysis. A NORM Radiological Survey must be performed at least two weeks prior to the commencement of works and is performed by a competent RPT (meter user). If the RPT measures 5 cps above background, a sample of the sludge must be collected for analysis by SQU prior to commencement of the cleaning. Note: If the tank is double lined, the radiation may not reach the exterior wall and direct monitoring of the sludge is required. Once the oil is drained, a representative sample of the sludge shall be collected from the base of the tank. If a sample can be gathered without emptying the tank, this should be undertaken along with the NORM Survey. If the sludge does not exceed 5 cps above background, there is insufficient NORM to warrant implementing this procedure and the sludge or sands shall be treated at not NORM contaminated. It is necessary to collect a sludge sample for analysis by SQU as this will determine the disposal options. The sample (> 100 grams) is analysed for isotopic Radium-226 activity. If the activity of the Radium-226 is greater than 1 Bq/g of sludge, the sludge must be stored in a dedicated NORM facility for correct future disposal. If the activity is less than 1 Bq/g for Radium-226, according to current international standards, the sludge can be land farmed to remove the hydrocarbon content. At less than 1 Bq/g of Radium-226, the external dose from the gamma radiation is not of significant risk, however the inhalation risk to workers performing sludge removal from alpha and beta particles is exists and controls to prevent inhalation, ingestion and absorption of NORM through open cuts is necessary. This procedure is developed when the exterior NORM Radiological Survey indicates the presence of NORM inside the tank. If NORM is not detected from exterior measurements of gas vessels, NORM may still be present in the interior (as Lead-210) and monitoring of the inside of the tank is required by the RPS/RPT using the Mini 900 with EP15 probe (alpha/beta meter) or equivalent. This document shall be read in conjunction with PR 1077 Preparation of Tanks and Vessel for Internal Work - Procedure 1.1 Objective To define radiological precautions for maintaining NORM contaminated vessels and tanks. 1.2 Scope This procedure shall apply to all PDO and Contractor personnel involved in cleaning, maintenance and inspection of vessels and tanks. Page 2
2. Responsibilities 2.1 Permit Applicant The Permit Applicant is responsible for requesting a NORM Radiological Survey be conducted prior to and during tank cleaning operations and is attached to the PTW. The survey must be conducted two (2) weeks prior to commencement of work. 2.2 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. Vessel and tank entries are regarded as non-routine jobs and therefore require the involvement of an RPS. As the tank cleaning and maintenance is performed by contractors, the contractor is responsible for providing a trained RPS to ensure these procedures are understood and adhered to. The RPS shall advise the Campaign Supervisor and RPT in relation to radiation issues. Note: the Mini 900 Meters used to undertake the NORM Radiological Survey are not intrinsically safe and a PTW shall be conducted to undertake the initial and ongoing NORM measurements. 2.3 Responsible Supervisor The Responsible Supervisor is responsible for verifying that the Permit Applicant has requested a NORM Radiological Survey for all tank cleaning 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, sand or scale. The Responsible Supervisor shall not sign the PTW to initiate entrance and cleaning of the tank without referring to the NORM Radiological Survey and the health and safety precautions sited by the RPS. 2.4 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 the NORM Guidelines. 2.5 Contractor The Contractor is responsible for ensuring that an appropriately trained RPT forms part of the tank cleaning 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. The contractor shall provide all the PPE required to perform the job and shall ensure that workers performing vessel inspections and cleaning are appropriately trained for all hazards, including NORM. The RPS is responsible for conducting and reviewing the initial external contamination measurements and advising on radiological controls. The RPS is responsible for undertaking internal measurements prior to workers entering the tank and shall be responsible for conducting and recording measurements throughout the work cycle. Page 3
3. Performance 3.1 PPE and auxiliaries Prior to commencing work, the PDO Campaign Supervisor shall ensure the contractor has sufficient PPE and auxiliaries. (NORM Guideline No. 3 outlines the PPE requirements). 3.2 Health & Safety Measures and Work Instruction 3.2.1 General All vessels and tanks shall be treated as NORM contaminated until RPS/RPT measurements prove otherwise. All personnel shall attend a NORM awareness course and be familiar with the health hazards and safeguards associated with NORM jobs. A tool box meeting shall be conducted prior to commencement of any work by the contractors with the Campaign Supervisor. The methodology shall be clearly understood by the contractors performing the work, especially explaining the risks involved exposure to NORM and the correct disposal/storage procedure. 3.2.2 Entering NORM Contaminated Vessels/Tanks Supervision by the Production and/or Maintenance Supervisor is recommended Cover the ground at the vessel/tank entrance with plastic sheet (HDPE). Create a supervised area using barrier tape to prevent unauthorised entry. Other safety measurements (gas test, etc.) shall be carried out prior to NORM measurements. The person carrying out these measurements shall wear all normal PPE and will be checked for contamination upon exit. N.B. The Mini 900 Instruments used for NORM tests are NOT rated for classified areas (i.e. not intrinsically safe). RPT shall enter the tank and measure for radiation and contamination. After leaving the vessel/tank the RPT will check himself for contamination. RPT shall register any measurements and NORM precautions on a Radiological Survey and NORM Survey Report found in Appendix A of SP 1170 Version 3.0. NORM procedures are required if the measurements exceed 5cps above background with the Mini 900/44A meter. All persons shall be checked for contamination on exit from the Supervised/Controlled Area. If personal contamination is found it shall be noted and Decontamination of Personnel followed. Note: NORM Guideline No. 9 provides advice on how to decontaminate personnel. Page 4
Equipment used inside the Supervised/Controlled Area shall be checked for contamination prior to removal. Any equipment which can not be cleaned shall be bagged, sealed and marked externally as NORM contaminated with activity levels and logged using the NORM Forms in Appendix C and D of SP 1170. Any waste generated shall be checked for NORM contamination and if activity is found, placed in drums and logged in the NORM Forms in SP 1170. NORM Contaminated waste in drums shall be transported to the NORM storage yard in Bahja. Sludge in quantities to warrant drum handling inefficient should be stored in HDPE lined pits in the respective Assets Waste Treatment Facility. Do not sludge Farm NORM contaminated sludge which exceeds 1 Bq/g for Ra-226. 3.2.3 Cleaning NORM Contaminated Vessels / Tanks Supervision by the Maintenance Supervisor (see Paragraph 2.3) or his nominated deputy is mandatory. The tank shall be well ventilated (push-pull systems) before work commences and shall continue throughout the cleaning process. The tank and surrounding should have restricted access and shall be limited to trained personnel with appropriate PPE. If the dose where workers operate exceeds 2.5 usv/hr but is less than 7.5 usv/hr that area becomes a Supervised Area. ( 2.5 usv/hour to < 7.5 usv/hour) If the dose rate exceeds 7.5 usv/hour where workers operate, contact the CRFP for further advice before commencing work. Radiological Surveys and precautions must be carried out by a competent RPT as a minimum. RPS creates a Supervised or Controlled Area depending on the dose. The Campaign Supervisor and RPS shall ensure other workers in the tank bund area are not at risk of exposure to airborne sludge or dusts. If the work is urgent, the Maintenance Supervisor in conjunction with the Production Operator shall decide if they also require PPE. Special precautions shall be taken to prevent the spread of contamination to unsupervised areas by using plastic sheeting or plastic lined bunds. Where possible, use a vacuum truck to suck as much liquid from above the sludge as possible. This emulsion will contain NORM sludge/sands in the liquid phase and if pumped into the main oil line will end up in the MAF tanks. Excavate a pit outside the D-gate and line it with HDPE to enable sludge to be vacuum pumped. Once all the liquid phase has been removed by the vacuum truck open the D-gate and allow the remaining material to flow into the pit. Any liquid can be collected by the vacuum truck. Deposit the sludge into dedicated NORM pits for disposal. Where the vacuum truck can no longer suck the liquid sludge, the use of a high pressure water hose from the port hole shall be used to flush the solids out through the D-Gate. If the sludge is very hard, the use of devices to break up the cake into a powder/fragments should be considered to allow the Page 5
high pressure water hoses to flush the material into the pit for collection with the vacuum truck. Solids which cannot be removed by the above method, will have to be hand shovelled into wheel burrows and depending on the quantity placed into drums or into tippers to go to the dedicated NORM pits. Workers entering into NORM contaminated tanks shall wear air supplied respiratory protection. Workers outside the tank will wear PPE at the advice of the RPS. If potential for airborne sludge exists, as a minimum a disposable half-face P3 respirator shall be worn. All wastes generated shall be checked for contamination and placed in drums for transport and storage. Solids shall be stored in designated drums with sealable lids for storage in the Bahja NORM yard. All personnel shall be checked for contamination on exit from the Supervised/Controlled Area. If contamination is found it shall be removed. Guideline 9 Decontamination of personnel provides further advice. The area around the tank shall be checked for NORM contamination. Where the soil is found to be contaminated, the soil shall be collected. Depending on the quantity will determine the method of collection. NORM Contaminated waste shall be transported to the nearest NORM yard as per SP 1170. The Transport forms in SP 1170 Appendix B & C shall be completed and attached with the load and provided to the operator as the NORM Yard. Page 6
Glossary of Abbreviations Appendix 1 PPE RPT RPS CRFP Personal Protective Equipment Radiation Protection Technician Radiation Protection Supervisor Corporate Radiation Focal Point Page 7