IR 05000133/2006002

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IR 05000133-06-002; Pacific Gas and Electric Company, Inspection Conducted on 03/27-31/2006 at the Licensee'S Humboldt Bay Power Plant Unit 3 Facility
ML061100212
Person / Time
Site: Humboldt Bay
Issue date: 04/20/2006
From: Spitzberg D
NRC/RGN-IV/DNMS/FCDB
To: Keenan J
Pacific Gas & Electric Co
References
IR-06-002
Download: ML061100212 (16)
v • d • e


Text

ril 20, 2006

SUBJECT:

NRC INSPECTION REPORT 050-00133/06-002

Dear Mr. Keenan:

An NRC inspection was conducted on March 27-31, 2006, at your Humboldt Bay Power Plant Unit 3 facility. This inspection was an examination of activities conducted under your license as they relate to safety and compliance of the Commissions rules and regulations and with the conditions of your license. Within these areas, the inspection included reviews of your maintenance, occupational radiation exposure, and radioactive waste treatment and effluent and environmental monitoring. On March 31, 2006, at the conclusion of the site visit, an exit briefing was conducted with Mr. Roy Willis, Plant Manager, and other members of your staff.

The enclosed report presents the scope and results of that inspection. The inspection determined that you were conducting decommissioning activities in compliance with regulatory and license requirements.

In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its enclosure, and your response (if any) will be made available electronically for public inspection in the NRC Public Document Room or from the NRC's document system (ADAMS), accessible from the NRC Web site at http://www.nrc.gov/reading-rm/Adams.html. To the extent possible, your response should not include any personal privacy, proprietary, or safeguards information so that it can be made available to the public without redaction.

Should you have any questions concerning this inspection, please contact the undersigned at (817) 860-8191 or Emilio M. Garcia at (530) 756-3910.

Sincerely,

/RA/

D. Blair Spitzberg, Ph.D., Chief Fuel Cycle and Decommissioning Branch Docket No.: 050-00133 License No.: DPR-7

Enclosure:

NRC Inspection Report 050-00133/06-002

Pacific Gas and Electric Company -2-

REGION IV==

Docket No.: 050-00133 License No.: DPR-7 Report No.: 050-00133/06-002 Licensee: Pacific Gas and Electric Company (PG&E)

Facility: Humboldt Bay Power Plant (HBPP), Unit 3 Location: 1000 King Salmon Avenue Eureka, California 95503 Dates: March 27-31, 2006 Inspectors: Emilio M. Garcia, Health Physicist, Approved By: D. Blair Spitzberg, Ph.D., Chief Fuel Cycle and Decommissioning Branch Attachments: 1) Supplemental Inspection Information 2) Partial List of Documents Reviewed ADAMS Entry: IR 05000133-06-02, on 03/27-31/06; Pacific Gas & Electric Co.;

Humboldt Bay, Unit 3. No violations.

-2-EXECUTIVE SUMMARY Humboldt Bay Power Plant, Unit 3 NRC Inspection Report 050-00133/06-002 The Humboldt Bay Power Plant (HBPP), Unit 3 was shutdown in 1976. The facility has been in a SAFSTOR status since shutdown with minimal decommissioning activity.

Maintenance and Surveillance

  • The licensee successfully completed a project to remove contaminated resin from the Off-gas Pipe Tunnel, an enclosed underground concrete tunnel. The resin had spilled from a broken pipe in the tunnel. The tunnel had contained the spilled resin. The licensee also removed the resin from the remainder of the pipes and from the Spent Fuel Pool (SFP) Demineralizer tank. Licensee personnel worked carefully and safely to adhere to procedural requirements (Section 1).

Occupational Radiation Exposure

  • The licensee had developed a comprehensive, special radiation work permit to control the work related to the Off-gas Pipe Tunnel resin cleanup and SFP Demineralizer resin flush. The inspector concluded that overall the licensee had effectively limited the radiation exposure to personnel while recovering and containing a significant source of radiation (Section 2).

Radioactive Waste Treatment and Effluent and Environmental Monitoring

  • There had been no detectable tritium in monitoring wells since January 2001. The historical values detected in 1980's and 1990's were a fraction of the USEPA drinking water standard. There are no drinking water wells or other sources hydrologically down gradient from the site. Tritium or other radionuclide contamination of drinking water was not a problem at this site (Section 4.1).
  • The 2005 Annual Radioactive Effluent Release Report was submitted on a timely basis and met applicable regulatory requirements. The report documented that the releases of radioactivity in gaseous and liquid effluents in 2005 did not exceed applicable regulatory limits (Section 4.2).

-3-Report Details Summary of Plant Status Humboldt Bay Power Plant, Unit 3, is currently in decommissioning SAFSTOR status. Unit 3 received an operating license from the Atomic Energy Commission on August 28, 1962. On July 2, 1976, Unit 3 was shutdown for annual refueling and seismic modifications. This work was suspended in December 1980 and in June 1983, then PG&E announced its intention to decommission the unit. Unit 3 has been essentially in SAFSTOR since July 1985. On July 19, 1988, NRC approved the licensees SAFSTOR plan and amended the license to a possess-but-not-operate status. The license will expire on November 9, 2015. The facility has undergone minimal decommissioning activity since shutdown.

1.0 Maintenance and Surveillance (IP 62801)

a. Inspection Scope The inspector reviewed the licensees preparations and conduct of the off Gas Pipe Tunnel resin cleanup and spent fuel pool (SFP) demineralizer flush project.

b. Observations and Findings During the spring of 2005, the licensee determined that the demineralizer resin used to maintain the SFP water quality was approaching its useful life and needed to be replaced. When attempting to slurry the used resin from the SFP demineralizer tank to the resin disposal tank the transfer pipe became plugged. The licensee determined that the presence of fine particulates that collected in the SFP demineralizer tank were a significant contributor to the pipe plugging. These fine particulates resulted from the increased work in the SFP during 2004 and 2005 and had not been present in this quantity during previous resin removals. Several means to unplug the resin transfer pipe were attempted with no success. Finally, on August 5, 2005, the licensee installed a manifold on the demineralizer system to permit the use of pressurized water from the plant fire protection system. The fire protection system water can reach a pressure of 150 pounds per square inch gauge (psig).

When the 150 psig water pressure was applied to this system the resin started to move, but soon a gasket failed and some resin spilled into the SFP demineralizer room. The licensee stopped work in this project, initiated cleanup of the SFP demineralizer room and begun to evaluate means of removing the remaining resin from SFP demineralizer, thus putting the transfer pipe back in service.

Increases in radioactivity in the Liquid Radioactive Waste Receiver Tank and the Turbine Building Drain Tank lead the licensee staff to identify that the resin transfer pipe had also failed inside the Off-Gas Pipe Tunnel. The Off-Gas Pipe Tunnel is an L-shaped underground concrete tunnel leading from the plant vent, going partially under the fuel handling building and ending in the plant yard near the staircase to the +27-foot level. The Off-Gas Pipe Tunnel contained a number of pipes, including the resin transfer pipe.

-4-On February 8, 2006, the licensee staff performed and entry into the Off-Gas Pipe Tunnel and found approximately 2 to 4 cubic feet of resin. The resin spilled into the Off-Gas Pipe Tunnel from a break in the resin transfer pipe. This pipe was observed to be severely corroded. The corrosion was due to intruding ground water dripping on the pipe from cracks in the ceiling of the Off-Gas Pipe Tunnel. The licensee believes that the corroded pipe could not withstand the increased pressure of the fire system water and that was why it failed. Radiation levels measured on contact with the resin transfer pipe suggested the presence of resin in the entire pipe before and after the pipe break.

The licensee developed a plan of action to collect the spilled resin, clear the plugged pipes, and empty the demineralizer tank of the used resin. To achieve these goals the licensee:

  • Designated a senior experienced radiation protection professional to lead the project.
  • Brought additional trained personnel from another licensee operated nuclear reactor site to supplement the onsite personnel.
  • Arranged for a contractor to provide pumps and resin receiver tank or storage vessel for collecting the contaminated resin, and an in-pool demineralizer to replace the disabled one.
  • Developed a specific procedure and permits for the work to be performed.

Prior to the initiation of cleanup work, two preliminary entries into the Off-gas Pipe were made. These entries were to collect additional data needed for the project, to place a video camera for remote observation of conditions in the vault during the various aspects of the project, and to evaluate the condition of the tunnel.

Examination of the video collected during these entries lead a licensees specialist in concrete to conclude that the leaks into the tunnel were mostly at the construction joints at the ceiling and the top two feet of the walls. There were no circumferential cracks.

This specialist concluded that the tunnel was structurally sound. A licensee specialist on hydrology concluded that the surrounding groundwater had a higher piezometric level, or head, than the tunnel so the potential is for water to flow slowly into the tunnel and not out of the tunnel. The licensee concluded that the Off-gas Pipe Tunnel had contained the spilled resin.

The inspector reviewed the original, and revisions 1 and 2 of Temporary Procedure (TP)

2006-03, Off-gas Pipe Tunnel Resin Cleanup and SFP Demineralizer Resin Flush. This was the principal procedure for this project. This procedure identified five phases for the cleanup as follow: 1) removal of large debris from tunnel and installation of a protective standpipe on the tunnel drain; 2) clearing the resin from the transfer pipes; 3) setting up the resin receiver tank or storage vessel and its associated shielding; 4) transferring of the resin from the Off-Gas Pipe Tunnel to the resin receiver tank; and 5) transferring the

-5-resin in the condensate demineralizer room and SFP demineralizer, and associated piping, to the resin receiver tank. For each of these phases an Appendix to the procedure had been developed.

The inspector observed several of the pre-job briefings conducted prior to each days work. These briefings described the goals for the day, job prerequisites, and individuals responsibilities. The participants on these pre-job briefings were attentive and they asked questions and requested clarifications. During these pre-job briefings, a Job Safety Analysis and special (radiation) work permit (SWP) briefings were also conducted.

During the pre-job briefing conducted on March 28, the inspector observed that the briefing referred to Appendix 8.1 of the procedure, which addressed the removal of large debris from the pipe tunnel and installation of a protective standpipe on the tunnel drain.

However, one of the goals discussed was cutting into the resin drain pipe. Cutting into the resin transfer pipe was not in Appendix 8.1 but was in Appendix 8.3. When the inspector brought this discrepancy to the Project Managers attention the work did not proceed until additional flexibility was written into the temporary procedure.

The inspector observed successful completion of the first four phases of the temporary procedure. Subsequent to the site visit, the licensee informed the inspector that phase five had also been successfully completed. The inspector noted that although the project had experienced a number of delays due to minor problems, the licensee personnel worked carefully, safely, and adhered to procedural requirements.

c. Conclusions The licensee successfully completed a project to remove contaminated resin from the Off-gas Pipe Tunnel, an enclosed underground concrete tunnel. The resin had spilled from a broken pipe in the tunnel. The tunnel had contained the spilled resin. The licensee also removed the resin from the remainder of the pipes and from the Spent Fuel Pool Demineralizer tank. Licensee personnel worked carefully, safely, and adhered to procedural requirements.

2.0 Occupational Radiation Exposure (IP 83750)

a. Inspection Scope The inspector reviewed the licensees radiation protection preparations and practices in support of the Off-gas Pipe Tunnel resin cleanup and SFP Demineralizer resin flush.

b. Observations and Findings As described in Section 1 above, the licensee needed to cleanup a spill of contaminated resin from the Off-gas Pipe Tunnel and remove the remaining resin from SFP Demineralizer tank and associated pipes. The resin had been used for maintaining the water quality of SFP. The resin had not only removed dissolved contaminants but had also entrapped fine particles present in the SFP water. Some of these particles were

-6-special nuclear material waste from damaged fuel. During the initial entry into the Off-gas Pipe Tunnel, contact radiation dose rates with the resin pile was measured at 4,000 millirem per hour.

The inspector reviewed the SWP 2006-0112, that the licensee had prepared for this job.

The SWP identified three tasks: 1) area setup with no high-high radiation area entries and no off-gas tunnel entry; 2) SFP Demineralizer vault work including setup, resin transfer, and tear down; and 3) Off-gas Pipe Tunnel work and resin transfer from the Off-gas Pipe Tunnel.

The SWP specified dosimetry, respiratory protection, protective clothing, and detailed worker instructions. Dosimetry included not only the normally assigned thermo-luminescence dosimeter (TLD) and electronic dosimeter but additional TLD dosimeters at ankles and wrists, as well as lapel air samplers. The SWP also required continuous air monitors or general area air samples on access points. Respiratory protection was provided by pressurized air power respirators when working with open sources. The protective clothing not only included the normal cloth coveralls, cloth hood, integral booties, and disposable rubber gloves but also included rubber boots and plastic suits when working in the Off-gas Pipe Tunnel.

Additional radiological safety was provided by requiring verification of the operation of the plant ventilation system, continuous attendance of a radiation protection technician when entering high or high-high radiation areas, and the operation of the high efficiency particulate absorbers (HEPA) ventilation system for at least 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> prior to entry into the Off-gas Pipe Tunnel. There were additional radiation protection technicians at the access and egress points to assist with removal of protective clothing. Sea-vans had been placed over each of the access points into the Off-gas Pipe Tunnel. These structures provide improved protection from the environment and easier access, and could be locked to assure control into the high-high radiation area. Time keeping was used during entries into the Off-gas Pipe Tunnel to calculate DAC-hours based on lapel air sampler data.

An as low as reasonably achievable (ALARA) review and job planning had been performed and an estimate of 1.1985 person-rem had been projected for the SWP with an ALARA goal of 1.0 person-rem. Subsequent to the site visit, the licensee provided the inspector with their dose estimates based on electronic dosimeter readings. Workers on this SWP had received a commutative dose of 1.266 person-rem. TLD results were expected to be consistent with these numbers. This value was approximately 6 percent above the projected dose. The Radiation Protection Manager stated that this increase in the commutative dose was due to an expanded scope of work.

The inspector observed significant portions of the entry into the Off-gas Pipe Tunnel and the SFP Demineralizer Vault. The inspector did not observe any instance where the requirements of the SWP were not followed.

Two individuals were assigned additional dose to the skin of the whole body due to skin contamination. One individual received an 0.058 rad skin dose due to a cut on his plastic suit at the knee. This skin contamination occurred as the result of his plastic suit

-7-tearing while crawling under some piping. It occurred during one of preparatory entries and the licensee added knee pads to the outfits to prevent recurrence. The licensee also opened an alternate south access to the Off-gas Pipe Tunnel to facilitate some of the entries. The other individual was assigned 0.023 rad to the skin of the whole body.

This skin contamination appeared to have occurred during the removal of his protective clothing, but the licensee conservatively calculated the dose based on the entire time in the tunnel.

Two individuals had positive whole body counts following the work so the licensee had them collect their excretions for in-vitro bioassay for further evaluation. The in-vitro samples indicated that one individual was not internally contaminated. For the other individual, the in-vitro bioassay identified a small amount of internal contamination. The licensee was continuing to evaluate this data however, the Radiation Protection Manager stated that he expected that the committed effective dose equivalent would be less than 0.005 rem. The NRC will review the final results of this determination during a future inspection.

c. Conclusions The licensee had developed a comprehensive special radiation work permit to control the work related to the Off-gas Pipe Tunnel resin cleanup and SFP Demineralizer resin flush. The inspector concluded that overall the licensee had effectively limited the radiation exposure to personnel while recovering and containing a significant source of radiation.

4.0 Radioactive Waste Treatment and Effluent and Environmental Monitoring (84750)

4.1 Review of Inadvertent Releases of Radioactive Liquids to Groundwater a. Inspection Scope The inspector reviewed historical and current status of tritium releases to groundwater.

b. Observations and Findings NRC Inspection reports 50-133/1997-002, 50-133/1998-01, 50-133/1998-03, 50-133/2000-01, and 50-133/2000-02 document tritium presence in two monitoring wells located onsite.

Table 2-8 of SAFSTOR Offsite Dose Calculation Manual (ODCM) specifies a reporting level for tritium of 20,000 picocuries per liter (pCi/l) in environmental samples. This value is based on the U. S. Environmental Protection Agency (USEPA) drinking water standard as listed in 40 CFR 141. If no drinking water pathway exits, the ODCM permits a reporting value of 30,000 pCi/l. The licensee, over the years, had used several different lower limits of detection (LLDs) for their analysis of tritium in groundwater samples. The LLD had ranged from 400 to 3000 pCi/l. The hydrological gradient of the

-8-plant site is inclined toward Humboldt Bay and there are no drinking water wells down gradient from the plant site registered with the County of Humboldt, California. The closest drinking water well to the site is a Humboldt Community Services District Well approximately 0.4 miles away and up gradient from the site.

During its operating period 1963 through 1976, the site experienced a number of onsite spills that included tritium. Tritium had been historically detected in quarterly samples from monitoring well MW-11. The highest level was 7600 pCi/l detected in January 1985. Tritium levels at this well dropped until they were below the minimum detectable level of 500 pCi/l in the August 1997. An extensive evaluation was completed in 1999 which reviewed the historical site activities that could have resulted in tritium being released. A french drain that ran under the railroad track from Unit 3 to a location near well MW-11 was found to have 3,190 pCi/l of tritium in 1997. The 1974 spill of contaminated water from the condensate demin room, which overflowed into the Unit 3 yard, was the most probable explanation of the tritium detected in well MW-11. Of the six monitoring wells, only one other well has had any detectable tritium. This was well MW-1 which, from August 1997 to January 2001, had occasional readings near the LLD.

These positive results ranged from 405 to 589 pCi/l. All six site monitoring wells showed no tritium or other radionuclides above minimal detectable levels in the last 5 years.

c. Conclusions There had been no detectable tritium in monitoring wells since January 2001. The historical values detected in 1980's and 1990's were a fraction of the USEPA drinking water standard. There are no drinking water wells or other sources hydrologically down gradient from the site. Tritium or other radionuclide contamination of drinking water was not a problem at this site.

4.2 Annual Radioactive Effluent Release Report for 2005 a. Inspection Scope The 2005 Annual Radioactive Effluent Release Report was reviewed.

b. Observations and Findings Technical Specification 5.7.3 required that an Annual Radioactive Effluent Release Report be submitted prior to April 1 of each year. In accordance with 10 CFR 50.36(a),

the report must cover the activities of the previous calender year. On March 29, 2005, the licensee submitted the 2005 Annual Radioactive Effluent Release Report on a timely basis. The report included summaries of radioactive gaseous and liquid releases from the site. The report concluded that the releases of radioactivity in gaseous and liquid effluents were well below the 10 CFR 50 Appendix I numerical ALARA guidelines and that the maximum potential direct radiation dose was well below the limits of 10 CFR 20.1302(b)(2(ii).

-9-There were no abnormal gaseous or liquid releases during 2005. There were nine liquid batch releases during 2005 and no continuous liquid releases. There were no batch gaseous releases during 2005.

In 2005, there were no shipments of solid waste made.

The report included the latest revision to the ODCM, as required by Technical Specification 5.6.1c.3.

c. Conclusions The 2005 Annual Radioactive Effluent Release Report was submitted on a timely basis and met applicable regulatory requirements. The report documented that the releases of radioactivity in gaseous and liquid effluents in 2005 did not exceed applicable regulatory limits.

5.0 Follow-up (IP 92701)

(Closed) IFI 50-133/0503-02 Review licensees evaluation of August 3, 2005, SFP Demineralizer system gasket failure that resulted in spill of radiologically contaminated resin.

As noted on Section 1 of this report the licensee had installed an in-pool demineralizer to replace the disabled SFP demineralizer. The in-pool demineralizer was declared operable on March 10, 2006. Training for this system was completed on March 13, 2006. As of the time of the inspection, the associated design change notice and problem report had not been closed but knowledgeable licensee personnel indicated that all required tasks had been successfully completed. This IFI is considered closed.

6.0 Exit Meeting On March 31, 2006, at the conclusion of the site visit, the inspectors presented to the plant manager and other licensee staff members, the preliminary results on areas inspected. The licensee did not identify as proprietary any information provided to, or reviewed by, the inspectors.

ATTACHMENT 1 SUPPLEMENTAL INSPECTION INFORMATION PARTIAL LIST OF PERSONS CONTACTED J. Albers, Radiation Protection Manager M. Antony, Decontamination Technician J. Brimble, Maintenance Supervisor J. Chadwick, Radiation Protection Engineer J. Davis, Radiation Protection Engineer J. Galle, Senior Engineer R. Grey, Spent Fuel Pool Demineralizer Resin Project Manager M. Grossman, Operations Supervisor V. Jensen, Quality Control Supervisor J. Mason, Quality Assurance Supervisor G. McKinnon, Control Operator R. Parker, Senior Radiation Protection Engineer L. Pulley, ISFSI Project Manager J. Rasmussen, Certified Fuel Handler M. Stich, ECP Lead Investigator - Diablo Canyon M. Smith, Engineering Manager D. Sokolsky, Supervisor of Licensing R. Sorensen, Programs Coordinator R. Willis, Plant Manager INSPECTION PROCEDURES USED IP 62801 Maintenance and Surveillance IP 71801 Decommissioning Performance and Status Review ITEMS OPENED, CLOSED, AND DISCUSSED Opened None Closed 50-133/0503-02 IFI Review licensees evaluation of August 3, 2005, SFP Demineralizer system gasket failure that resulted in spill of radiologically contaminated resin.

Discussed None

-2-LIST OF ACRONYMS ALARA As Low As Reasonably Achievable CFR Code of Federal Regulations DAC Derived Air Concentration dpm/100 cm2 Disintegrations per Minute per 100 cm2 HEPA High Efficiency Particulate Absorbers IFI Inspection Followup Item IP Inspection Procedure LLD Lower Limit of Detection MW Monitoring Well ODCM Offsite Dose Calculation Manual pCi/l picocuries per liter psig pounds per square inch gauge SFP Spent Fuel Pool SWP Special (radiation) Work Permit TLD Thermo-Luminescence Dosimeter TP Temporary Procedure USEPA United States Environmental Protection Agency

ATTACHMENT 2 PARTIAL LIST OF DOCUMENTS REVIEWED

  • Humboldt Bay Temporary Procedure 2006-03, Off-gas Pipe Tunnel Resin Cleanup and SFP Demineralizer Resin Flush, revision 0, effective March 26, 2006.
  • Humboldt Bay Temporary Procedure 2006-03, Off-gas Pipe Tunnel Resin Cleanup and SFP Demineralizer Resin Flush, revision 1, effective March 28, 2006 @ 1730.
  • Humboldt Bay Temporary Procedure 2006-03, Off-gas Pipe Tunnel Resin Cleanup and SFP Demineralizer Resin Flush, revision 2, effective March 29, 2006 @ 1100.
  • HBPP Radiation Work Permit 2006-0112, Resin Transfer, Revision 0, effective 03/21/2006.
  • Default Pre-Job Airborne Assessment, in support of HBPP Radiation Work Permit 2006-0112, March 24, 2006.
  • ALARA Review and Job Planning Form, SWP/RWP 2006-0112, Flush resin from the Off-gas Tunnel and transfer resin from the SFP Demin to a receiver tank.
  • SAPN 1234343, Unable to sluice SFP Demin resin to RDT, as of March 31, 2006.
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