Discrete Radioactive Particle Issues Associated with a DRP Issues Discrete Radioactive Particle Issues Associated with a Fuel Pool Cleanout Project 7/14/2019 PPL Susquehanna LLC

Richard L. Doty and Richard C. Kessler Susquehanna Steam Electric Station Richard L. Doty and Richard C. Kessler 7/14/2019 PPL Susquehanna LLC

DRP Issues Management of Contamination Control Measurement Management Perception Culture 7/14/2019 PPL Susquehanna LLC

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 10-20 microns in diameter) with a specific activity greater than or equal to 50,000 cpm. 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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. 7/14/2019 PPL Susquehanna LLC

DRP Issues During the project, no individual was exposed to doses in excess of SSES or regulatory dose limits. 7/14/2019 PPL Susquehanna LLC

Assessments DRP Issues DRP of 8 Sv/h Series of DRP events Project management Independent oversight of project Critique of event evaluations 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

Regulatory Issues DRP Issues Significance Determination Process (SDP) identified a White Finding Notice of Violation - 10CFR20.1501 7/14/2019 PPL Susquehanna LLC

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.” 7/14/2019 PPL Susquehanna LLC

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.” 7/14/2019 PPL Susquehanna LLC

DRP Issues INPO Preliminary Operating Experience Report - Issued December 27, 2000 Assist Visit Recommendations - January Significant Event Report (SER) 3-01 - Issued March 30, 2001 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

DRP Issues WANO SER 2001-2 Risk assessments considering prior experience Contingency work plans for high-risk evolutions Thorough pre-job briefs and shift handovers 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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) 7/14/2019 PPL Susquehanna LLC

What Have We Learned DRP Issues We need to improve control of radioactive material on refueling floor and in potentially impacted systems 7/14/2019 PPL Susquehanna LLC

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. 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

DRP Issues Corrective Actions Treat high risk/high consequence evolutions as special evolutions Add management oversight for high risk activities Focus self-assessment program 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

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 7/14/2019 PPL Susquehanna LLC

DRP Issues QUESTIONS? 7/14/2019 PPL Susquehanna LLC