1. Discrete Radioactive Particle Issues Associated with a
DRP Issues
Discrete Radioactive Particle Issues Associated with a
Fuel Pool Cleanout Project
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PPL Susquehanna LLC

2. Richard L. Doty and Richard C. Kessler
Susquehanna Steam Electric Station
Richard L. Doty and Richard C. Kessler
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PPL Susquehanna LLC

3. DRP Issues Management of Contamination Control Measurement Management
Perception
Culture
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PPL Susquehanna LLC

4. What’s a Discrete Radioactive Particle (DRP)?
DRP Issues
What’s a Discrete Radioactive Particle (DRP)?
A DRP is defined as a fragment that is less than 1 mm in any dimension (typically microns in diameter) with a specific activity greater than or equal to 50,000 cpm.
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PPL Susquehanna LLC

5. OVERVIEW DRP Issues Project began in late June 2000
Control Rod Blade (CRB) processing began in July
First particle exposure to a worker (0.12 Sv, SDE) was documented on September 8th
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PPL Susquehanna LLC

6. DRP Issues
First high activity particle (20 mGy/h) was identified on September 11th
During removal of the Advanced Crusher Shearer on October 12th, a particle was identified with a measured contact dose rate of 8 Sv/h (a Telescan® was used).
Co-60 was identified via in-situ gamma spectroscopy
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PPL Susquehanna LLC

7. DRP Issues
On November 28th, a high activity particle was measured at 2.2 Sv/h on a cask.
On December 6th, a high activity Co-60 particle was identified on a worker’s shoe cover. The measured contact dose rate was 10 mSv/h.
Overall, 36 particles were identified between September 8th & December 15th.
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PPL Susquehanna LLC

8. DRP Issues
During the project, no individual was exposed to doses in excess of SSES or regulatory dose limits.
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PPL Susquehanna LLC

9. Assessments DRP Issues DRP of 8 Sv/h Series of DRP events
Project management
Independent oversight of project
Critique of event evaluations
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PPL Susquehanna LLC

10. 8 Sv/h Co-60 DRP on skin can result in:
DRP Issues
8 Sv/h Co-60 DRP on skin can result in:
2,900 Gy/h shallow dose equivalent
2.3 Gy/h deep dose equivalent
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PPL Susquehanna LLC

11. Regulatory Issues DRP Issues
Significance Determination Process (SDP) identified a White Finding
Notice of Violation - 10CFR
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PPL Susquehanna LLC

12. From the NRC Inspection report:
DRP Issues
From the NRC Inspection report:
“…(SSES) did not adequately evaluate and characterize the radiation exposure hazards posed by radioactive particles having highly significant activity.”
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PPL Susquehanna LLC

13. From the NRC Inspection report:
DRP Issues
From the NRC Inspection report:
“…(SSES) did not establish and implement adequate radiological safety controls to prevent shallow dose equivalent (SDE) and deep-dose equivalent (DDE) personnel exposures from exceeding regulatory requirements.”
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PPL Susquehanna LLC

14. DRP Issues
INPO
Preliminary Operating Experience Report - Issued December 27, 2000
Assist Visit Recommendations - January
Significant Event Report (SER) Issued March 30, 2001
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PPL Susquehanna LLC

15. SER 3-01 Recommendations DRP Issues
Documented guidance for establishing “HPCZ”
Thorough pre-job briefings
Well-developed contamination control methods, considering all applicable industry events
Senior management presence and communication of high standards
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PPL Susquehanna LLC

16. DRP Issues
WANO SER
Risk assessments considering prior experience
Contingency work plans for high-risk evolutions
Thorough pre-job briefs and shift handovers
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PPL Susquehanna LLC

17. Susquehanna Perspective on Root Causes
DRP Issues
Susquehanna Perspective on Root Causes
Inaccurate risk perception for exposure to DRP
Process focus on actual doses vs. potential doses
Inadequate pre-job plans for DRP controls
Unresolved cultural issues regarding questioning
attitude, communications, use of operating
experience
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PPL Susquehanna LLC

18. DRP Issues
What Have We Learned
Lack of sensitivity to the consequences of highly radioactive material (particles) (Root Cause 2)
Attitude that significant radiological events can’t happen at SSES
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PPL Susquehanna LLC

19. What Have We Learned DRP Issues
Particle assessments focused on actual doses versus potential doses (Root Cause 2)
Inadequate pre-job plans were developed for the FPCO project for the control of particles (Root Cause 4)
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PPL Susquehanna LLC

20. What Have We Learned DRP Issues
We need to improve control of radioactive material on refueling floor and in potentially impacted systems
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PPL Susquehanna LLC

21. What Have We Learned DRP Issues
The associated vacuuming and filtration of the cask storage pit (CSP) were less than adequate to control the DRP source term.
Rinsing of all items that were removed from the CSP and fuel pools was not performed for every evolution.
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PPL Susquehanna LLC

22. What Have We Learned DRP Issues
Need to structure pre-job briefings for hot particle control zone (HPCZ) work
Need specific RWPs for HPCZ work
Need to consider the use of respiratory protection to prevent the intake of particles
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PPL Susquehanna LLC

23. DRP Issues
What Have We Learned
Radiation Protection Technicians needed more training on DRP survey and containment techniques
Self-assessment program was not sufficiently risk-oriented
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PPL Susquehanna LLC

24. DRP Issues
Corrective Actions
Revised RP procedures to enhance radiological controls
Survey techniques
Labeling and posting
Dose rate limits and dress requirements
Control of radioactive material
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PPL Susquehanna LLC

25. DRP Issues
Corrective Actions
Treat high risk/high consequence evolutions as special evolutions
Add management oversight for high risk activities
Focus self-assessment program
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PPL Susquehanna LLC

26. DRP Issues
Summary
Be proactive to potential conditions rather than reactive to emergent conditions
When the mindset exists that “it can’t happen here,” it will
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PPL Susquehanna LLC

27. INPO SER 4-98 addressed precursors for unplanned exposures
DRP Issues
INPO
SER 4-98 addressed precursors for unplanned exposures
Three of the root causes aligned with the SER precursors
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PPL Susquehanna LLC

28. INPO SER 4-98: Common Event Precursors
DRP Issues
INPO SER 4-98: Common Event Precursors
Inaccurate or incomplete radiological surveys
Inadequate work planning and radiation work permits
Incorrect guidance provided by radiological protection technicians
Non-compliance with radiological protection rules
Ineffective supervisory and management direction and oversight
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PPL Susquehanna LLC

29. Comprehensive planning Accurate risk perception
DRP Issues
Defense in Depth
Strong management
Comprehensive planning
Accurate risk perception
Culture of awareness and risk control
Good measurement processes
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PPL Susquehanna LLC

30. DRP Issues
QUESTIONS?
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PPL Susquehanna LLC