ML22067A185
| ML22067A185 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 03/01/2022 |
| From: | Energy Northwest |
| To: | NRC Region 4 |
| Greene N | |
| Shared Package | |
| ML22067A190 | List: |
| References | |
| EA-21-170 | |
| Download: ML22067A185 (28) | |
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NRC Regulatory Conference - March 1, 2022 Columbia Generating Station Reactor Water Cleanup Uptake Event Regulatory Conference March 1, 2022 1
NRC Regulatory Conference - March 1, 2022 Introduction and Agenda Introduction and Agenda Desirée Wolfgramm, Regulatory Affairs Manager Management Overview Dave Brown, Site Vice President Event Description Tony Hedges, Chemistry/Radiological Services Manager Root Cause and Corrective Actions Sam Nappi, Assistant Chemistry/Radiological Services Manager Significance Determination Desirée Wolfgramm, Regulatory Affairs Manager Closing Comments Grover Hettel, Vice President Nuclear Generation / Chief Nuclear Officer 2
NRC Regulatory Conference - March 1, 2022 Management Overview Dave Brown Site Vice President 3
NRC Regulatory Conference - March 1, 2022 4
NRC Regulatory Conference - March 1, 2022 Event Description Tony Hedges Chemistry/Radiological Services Manager 5
NRC Regulatory Conference - March 1, 2022 Reactor Water Cleanup Heat Exchanger Replacement Major activities of the project:
- Preparing system for replacement of components
- Performing destructive chemical decontamination of heat exchangers and piping
- Removal of old components from the room
- Installing new components and welding new pipe to system piping The planning and staffing aspects:
- Dedicated Radiation Protection (RP) Technician with planning qualifications
- Planning incorporated elevated and high-risk aspects of the project
- Planning addressed Locked High Radiation Area (LHRA) controls, contamination and airborne controls
NRC Regulatory Conference - March 1, 2022 RP Preplanning for Weld Preparations
- Remote dose and dose rate monitoring
- Visual monitoring by camera
- Portable video cameras, placed by RP, monitored at remote monitoring station (RMS)
- Supervisory oversight - required per procedure 11.2.7.3
- PROVIDE direct oversight during activities that have a potential for unplanned exposures, such as:
- Work involving Dose Significant Activities as defined by this procedure
- Diving operations into pools, tanks, or cavities
- Radiography
- Access to plant components that contain or may contain highly radioactive materials 7
NRC Regulatory Conference - March 1, 2022 Pre-Work Activities Cut Location #3 - As seen through cameras at Remote Monitoring Station May 27 - Nightshift - glove bag task preview at the mock-up with pipefitters, RP Lead Tech, and RP Tech #3
- Mock-up not effectively used for practice
- Decision to use smaller glove bag
- Pipefitters controlled installation and removal of glove bag May 28 - Dayshift - Successful weld prep on Cut #4 using larger glove bag under RP control
- Mock-up used for practice
- Used larger glove bag
- RP controlled installation and removal of glove bag 8
NRC Regulatory Conference - March 1, 2022 Uptake Event
- May 28 - Nightshift
- Project Team Pre-job Brief and LHRA Brief
- RP Job Coverage Tech changeout from RP Tech #1 to RP Tech #2
- Glove bag was removed contrary to briefed steps
- Pipe was wiped inside and out after glove bag removal
- Actions performed after glove bag removal were observed by RP Lead Tech and RP Supervisor via cameras at RMS
- RP Lead Tech directed RP Tech #1 to stop work
- RPT #1 directed pipefitters to cover pipe and exit
- Bag installed over pipe, then removed and foreign material exclusion (FME) cover installed, leaving jobsite in a safe condition 9
NRC Regulatory Conference - March 1, 2022 Briefed Steps Performed Steps
- Removed pipe plug in plastic bag
- Removed pipe plug in plastic bag
- Wetting a FME plug inside of a glove bag
- Wetting a FME plug inside of a glove bag
- Installing the glove bag onto the cut location
- Installing the glove bag onto the cut location
- Attaching a HEPA vacuum to the glove bag to control any
- Attaching a HEPA vacuum to the glove bag to control any contaminants contaminants disturbed during the work disturbed during the work
- Turning the HEPA vacuum on
- Turning the HEPA vacuum on
- Turning the HEPA vacuum off
- Installing the wetted FME plug into the pipe through the glove bag
- Installing the wetted FME plug into the pipe through the glove bag
- Cleaning the inside of the pipe using a flapping wheel inside of the
- Cleaning the inside of the pipe using a flapping wheel inside of the glove glove bag bag
- Removing the FME plug through the glove bag
- Removing the glove bag from the cut location
- Wetting down the inside of the pipe and wiping down the surfaces
- Wetting down the inside of the pipe and wiping down the surfaces with with the glove bag still in place the glove bag removed
- Removing the FME plug through the glove bag
- Removing the glove bag from the cut location
- Installing FME cover
- Installation of plastic bag, removal of bag and replaced with FME cover 10
NRC Regulatory Conference - March 1, 2022 Root Cause Clarifications
- Information discovered during the root cause investigation provides clarity on the sequence of events and circumstances of the night of May 28, 2021
- The following 5 slides provides this additional information 11
NRC Regulatory Conference - March 1, 2022 Additional Information from Root Cause Evaluation for ALARA Planning and Pre-Job Surveys Inspection Report Root Cause Clarifications
- The ALARA Work Plan included specific instructions
- The ALARA Work Plan was inclusive of the entire such as using powered air purifying respirators RWCU Project which did consist of work in PAPRs, (PAPRs) on highly contaminated components which included removal of old components from the room, the RWP was specific to the job of the uptake event
- there were inadequate surveys used to support
- Surveys 20210527-23 & 20210529-6, supported down-down-posting the RWCU HX area from a high posting the RWCU HX area to a contamination area contamination area to a contamination area 12
NRC Regulatory Conference - March 1, 2022 Additional Information from Root Cause Evaluation for Local Job Coverage Inspection Report Root Cause Clarifications
- Contrary to the RWP requirements for continuous job
- Continuous coverage was not required. Dose rates coverage, RP Tech #1 left the workers unattended were 450-550 mR/hr during the work at the jobsite location
- RP Tech #2 was not a part of the required formal
- RP Tech #2 was at LHRA brief the day of the uptake briefing for this job event but not the task preview 13
NRC Regulatory Conference - March 1, 2022 Additional Information from Root Cause Evaluation for Direct Oversight at Remote Monitoring Station Inspection Report Root Cause Clarifications
- There were three people at the RMS , RP Tech #3, RP not assigned to provide continuous coverage Lead Tech, and RP Supervisor
- The RP tech (not credited as job coverage) was at the
- In accordance with PPM 11.2.7.3 Step 3.4.1.b the RP remote monitoring station with a view of the glove Supervisor was providing direct oversight from the bag activity RMS
- the RP tech viewed the grinding activity at the right
- The RP Supervisor and RP Lead Tech both recognized point in time on the correct monitor and camera that steps were being performed out of the briefed sequence
- the RP tech had enough background information
- The RP Lead Tech was a part of the task preview at the and/or experience to recognize the abnormal mock-up, and RP Supervisor and RP Lead Tech were in situation the brief the day of the uptake event 14
NRC Regulatory Conference - March 1, 2022 Additional Information from Root Cause Evaluation for Job Completion Inspection Report Root Cause Clarifications
- the additional time needed to clean up the area,
- The pipefitters documented work complete. All gather tools, and leave the job in a safe work briefed steps were completed, some out of order. All condition is a reasonable scenario with minor tools were contained in the glove bag. The pipe was alterations could have led to overexposure covered by the FME cover when the pipefitters left the platform, leaving the job in a safe condition.
15
NRC Regulatory Conference - March 1, 2022 Additional Information from Root Cause Evaluation for Dose Assessment Inspection Report Root Cause Clarifications
- Airborne radioactive material was released from the
- Opportunities for airborne contamination include glove bag and dispersed into the RWCU HX room glove bag removal, wiping pipe inside and out, and installation and removal of plastic bag
- Based on the inspectors derived air concentration
- Based upon further investigation, there were multiple (DAC) estimate, the pipefitters could have reasonably opportunities for airborne contamination which received greater than 5 rem if they had remained in invalidates the assumption in the calculation that the the work area for an additional five minutes. These entire dose was received in one puff release estimates were confirmed by the results of the licensees Calculation 21-02.
16
NRC Regulatory Conference - March 1, 2022 Root Cause and Corrective Actions Sam Nappi Assistant Chemistry/Radiological Services Manager 17
NRC Regulatory Conference - March 1, 2022 Results of Causal Evaluations
- Direct Cause:
- Improper setup, use (without HEPA vacuum), and removal of a glove bag (engineering control) while performing pipe preparation activities.
- Root Cause:
- The Radiological Risk for the work was evaluated by staff presupposing the successful use of engineering controls to mitigate radiological hazards and didnt evaluate or recognize the overall risk associated with the work being performed or potential consequences of engineering control failure or incorrect use.
18
NRC Regulatory Conference - March 1, 2022 Completed Corrective Actions
- Immediate Corrective Actions:
- Stopped work
- Assigned additional resources
- Performed coaching to the RP supervision and Leads
- Ensured the remaining cuts were completed appropriately
- Actions Taken Since the Uptake Event
- Revised the radiological risk screening form for high contamination work
- Revised the Radiation Work Permit (RWP) procedure and Contamination Control Containment Devices procedure
- Developed a new procedure for RP outage preparation 19
NRC Regulatory Conference - March 1, 2022 Corrective Actions
- Additional Actions to Be Taken:
- Revising the radiological risk assessment procedure
- Provide training to individuals on how to assess radiological risk when elimination or mitigation actions are prescribed
- Revising the TEDE/ALARA evaluation process
- Require RWP revisions to be screened for changes in risk classification
- Establishing clear roles and responsibilities for glove bag use in HPI-12.90
- Formally perform culpability assessments per station procedures for the individuals involved 20
NRC Regulatory Conference - March 1, 2022 Significance Determination Desirée Wolfgramm Regulatory Affairs Manager 21
NRC Regulatory Conference - March 1, 2022 Performance Deficiency and Apparent Violations Performance Deficiency Energy Northwest agrees with the Performance Deficiency Apparent Violation #1 Energy Northwest agrees with Apparent Violation #1 but suggest some wording changes to reflect the issue. The engineering control was not planned for with enough specificity in accordance with station procedures, specifically HPI-12.90, to ensure proper control for installation and removal to prevent airborne contamination Apparent Violation #2 Energy Northwest disagrees with Apparent Violation #2. The dose rates in the area at the time of the uptake event were less than those requiring continuous coverage Apparent Violation #3 Energy Northwest disagrees with Apparent Violation #3. Adequate dose surveys were completed in the field by RP Technicians during the work activity 22
NRC Regulatory Conference - March 1, 2022 Inspection Report Significance Determination Assessed under the NRC's Reactor Oversight Process (ROP) Occupational Radiation Safety Significance Determination Process (SDP) Inspection Manual Chapter (IMC) 0609 Appendix C:
Finding Identified No No No No Was the ALARA Was It An Was there A Ability to Planning or Over- Substantial Assess Dose Green Work exposure? Potential? Compromised Controls?
?
Yes No Was it a No SDE/DRP Whole Body White Exposure? Exposure in a VHRA?
23
NRC Regulatory Conference - March 1, 2022 Substantial Potential for Overexposure IMC 0609 Appendix C II.C Substantial Potential for Overexposure An event presents a substantial potential when it was fortuitous that the resulting exposure did not exceed the limits of 10 CFR 20. The concern is not the significance of the resulting, or potential, exposure, but whether the licensee provided adequate controls over the situation, as required, to ensure the Part 20 dose limits are not exceeded. No credit is given for luck.
Required Controls per ALARA Plan and/or Station Procedures:
- Engineered Control - Glove bag
- Job coverage - RPT #2
- Direct Oversight - RP Supervisor at RMS
- Tele-dosimetry - RPT #3 at RMS 24
NRC Regulatory Conference - March 1, 2022 Substantial Potential for Overexposure (cont.)
IMC 0609 Appendix C II.C Substantial Potential for Overexposure (continued)
When assessing whether a finding constitutes a substantial potential for overexposure, consider if it is possible to construct a reasonable scenario in which a minor alteration of circumstances (as they actually happened) would have resulted in a violation of the Part 20 limits. The following circumstances should be considered: timing, source strength, distance, and shielding.
"Fortuitous" circumstances as described in the Inspection Report, but through the root cause investigation were found to be pre-planned in the ALARA Plan and/or station procedures:
- RP tech (not credited as job coverage) was at the remote monitoring station with a view of the glove bag activity
- The RP tech viewed the grinding activity at the right point in time on the correct monitor and camera
- The RP tech had enough background information and/or experience to recognize the abnormal situation
- The RP tech only had a "40 foot/30 second" walking path to the entrance of the RWCU HX room from the remote monitoring station 25
NRC Regulatory Conference - March 1, 2022 Alteration of Circumstances From Inspection Report If the lead RP tech had not intervened, the additional time needed to clean up the area, gather tools, and leave the job in a safe work condition is a reasonable scenario with minor alterations [that] could have led to overexposure.
Additional Clarification from further investigation:
- Calculation 21-002 assumptions are invalid
- Pipefitters completed work and left jobsite in a safe condition 26
NRC Regulatory Conference - March 1, 2022 Significance Determination Assessed with additional information discovered through the root cause under the NRC's ROP Occupational Radiation Safety SDP IMC 0609 Appendix C:
Finding Identified No No No No Was the ALARA Was It An Was there A Ability to Planning or Over- Substantial Assess Dose Green Work exposure? Potential? Compromised Controls?
?
Yes No Was it a No SDE/DRP Whole Body White Exposure? Exposure in a VHRA?
27
NRC Regulatory Conference - March 1, 2022 Closing Comments Grover Hettel Vice President Nuclear Generation /
Chief Nuclear Officer 28