ML052310593
| ML052310593 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 08/19/2005 |
| From: | Wert L Division of Nuclear Materials Safety IV |
| To: | Rueger G Pacific Gas & Electric Co |
| References | |
| EA-05-166, NMED 040585, NMED 050105 IR-05-002 | |
| Download: ML052310593 (62) | |
See also: IR 05000133/2005002
Text
August 19, 2005
NMED Nos. 040585, 050105
Gregory M. Rueger, Senior Vice
President, Generation and Chief Nuclear Officer
Pacific Gas and Electric Company
Diablo Canyon Power Plant
P.O. Box 3
Avila Beach, CA 93424
SUBJECT: HUMBOLDT BAY POWER PLANT UNIT 3 - NRC SPECIAL INSPECTION
FINAL REPORT 050-00133/05-002
Dear Mr. Rueger:
This refers to the special inspection initiated on November 2, 2004, at the Humboldt Bay Power
Plant (HBPP) Unit 3 facility. The purpose of the special inspection was to review the
circumstances of the reported loss of three approximately 18-inch long spent fuel rod
segments, one intact incore detector, and parts of three other incore detectors all containing
special nuclear material (SNM). An interim inspection report was issued on April 5, 2005, that
described the inspection activities through March 31, 2005. On June 20-24, 2005, a team of
inspectors visited HBPP to complete the inspection. Subsequent to this site visit inspectors
interviewed personnel, and reviewed and evaluated licensee documents submitted after the
visit. The inspection activities were concluded on August 2, 2005. On August 16, 2005, a
telephonic exit interview was conducted with you and members of your staff to discuss the
inspection results.
This report documents the NRCs assessment of: Pacific Gas and Electrics (PG&E) current
control of SNM; accountability for the remainder of the SNM in the spent fuel pool; the
adequacy of PG&Es investigation into the circumstances that led to the loss of accountability of
the missing SNM; the potential radiological consequences of the postulated scenarios involving
the missing SNM; and compliance with applicable regulations.
The NRC special inspection team determined that your investigation was thorough and
complete, and the conclusions were reasonable and supportable. The NRC also found that
once these matters were identified by PG&E, you promptly and accurately notified the NRC and
kept it informed throughout the process of search and investigation.
The NRC staff concluded that the current material control and accounting program being
implemented at the Humboldt Bay Power Plant meets regulatory requirements. In addition, the
NRC team agreed with your conclusion that there is no evidence to support theft or diversion of
the missing SNM, and this is not a plausible scenario. The NRC teams conclusions differed
Pacific Gas and Electric Company -2-
from yours in one notable respect. The NRC team concluded that the most likely scenario for
the missing SNM is that it was inadvertently shipped to a low level waste burial site. While your
conclusions supported this as a possibility, your investigation concluded that the most likely
scenario for the missing spent fuel rod segments was that they are still in your spent fuel pool in
an altered condition.
Based on the results of this inspection, three apparent violations were identified and are being
considered for escalated enforcement action in accordance with the NRC Enforcement Policy.
The current Enforcement Policy is included on the NRCs Web site at www.nrc.gov; select
What We Do, Enforcement, then Enforcement Policy. The apparent violations involved
(1) the failure to keep records showing the inventory, transfer or disposal of the three 18-inch
segments of irradiated fuel and one complete and three partial incore detectors; (2) the failure
to establish, maintain, and follow adequate written material control and accounting procedures
sufficient to account for the SNM; and (3) the failure to conduct an accurate physical inventory
of all SNM in your possession at intervals not to exceed 12 months. The circumstances
surrounding these apparent violations, the significance of the issues, and the need for lasting
and effective corrective action were discussed with members of your staff at the inspection exit
meeting on August 16, 2005. As a result, it may not be necessary to conduct a predecisional
enforcement conference in order to enable the NRC to make an enforcement decision.
Before the NRC makes its enforcement decision, we are providing you an opportunity to either:
(1) respond to the apparent violations addressed in this inspection report within 30 days of the
date of this letter or (2) request a predecisional enforcement conference. If a conference is
held, it will be open for public observation. The NRC will also issue a Meeting Notice to
announce the conference. Please contact Dr. Blair Spiztberg, at (817) 860-8191 within 7 days
of the date of this letter to notify the NRC of your intended response.
If you choose to provide a written response, it should be clearly marked as a "Response to
Apparent Violations in Inspection Report No. 050-00133/05-002; EA-05-166, and should
include for each apparent violation: (1) the reason for the apparent violation, or, if contested,
the basis for disputing the apparent violation, (2) the corrective steps that have been taken and
the results achieved, (3) the corrective steps that will be taken to avoid further violations, and
(4) the date when full compliance will be achieved. Your response may reference or include
previous docketed correspondence, if the correspondence adequately addresses the required
response. If an adequate response is not received within the time specified or an extension of
time has not been granted by the NRC, the NRC will proceed with its enforcement decision.
In addition, please be advised that the number and characterization of apparent violations
described in the enclosed inspection report may change as a result of further NRC review. You
will be advised by separate correspondence of the results of our deliberations on this matter.
During a public meeting held in Eureka, California on September 29, 2004, to discuss the
missing spent fuel rod segments, the NRC indicated its intent to hold another public meeting in
the area at the conclusion of the special inspection to discuss the NRC findings. This public
meeting has been scheduled for the evening of September 15, 2005. A separate meeting
notice and agenda will be issued at least 10 days prior to this meeting.
Pacific Gas and Electric Company -3-
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its
enclosures, and your response (if you choose to provide one) will be made available
electronically for public inspection in the NRC Public Document Room or from the NRCs
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.
Sincerely,
/RA/
Leonard D. Wert Jr., Director
Division of Nuclear Materials Safety
Docket No.: 050-00133
License No.: DPR-7
Enclosure:
1. NRC Special Inspection Report
050-00133/05-002
2. Special Inspection Charter (ML042990566)
cc w/enclosure:
Donna Jacobs, Vice President
Nuclear Services
Diablo Canyon Power Plant
P.O. Box 56
Avila Beach, CA 93424
Richard F. Locke, Esq.
Pacific Gas and Electric Company
P.O. Box 7442
San Francisco, CA 94120
Roy B. Willis, Plant Manager
Pacific Gas and Electric Company
Humboldt Bay Power Plant
1000 King Salmon Avenue
Eureka, CA 95503
Chairman
Humboldt County Board of Supervisors
County Courthouse
825 Fifth Street
Eureka, CA 95501
Pacific Gas and Electric Company -4-
Law Office of Linda J. Brown, Esq.
300 Drakes Landing Road, Suite 172
Greenbrae, CA 94904
Regional Radiation Representative
U. S. Environmental Protection Agency
Region IX Office
75 Hawthorne Street
San Francisco, CA 94105
Dr. Richard Ferguson, Energy Chair
1100 llth Street, Suite 311
Sacramento, CA 95814
Dr. James F. Davis, State Geologist
Department of Conservation
Division of Mines & Geology
801 K Street MS 12-30
Sacramento, CA 95814-3531
Ed Bailey, Chief
Radiologic Health Branch
State Department of Health Services
P.O. Box 997414 (MS 7610)
Sacramento, CA 95899-7414
Director
Energy Facilities Siting Division
Energy Resources Conservation &
Development Commission
1516 9th Street
Sacramento, CA 95814
Gretchen Dumas, Esq.
Public Utilities Commission
of the State of California
5066 State Building
San Francisco, CA 94102
Redwood Alliance
P.O. Box 293
Arcata, CA 95521
James D. Boyd, Commissioner
California Energy Commission
1516 Ninth Street (MS 34)
Sacramento, CA 95814
Pacific Gas and Electric Company -5-
bcc w/enclosure (via ADAMS distrib):
BSMallett
TPGwynn
J. Dixon-Herrity, OEDO RIV Coordinator (JLD)
LWCamper, NMSS/DWM
DMGillen, NMSS/DWM/DCD
CMCraig, NMSS/DWM/DCD
JBHickman, NMSS/DWM/DCD
LDWert
CLCain
DBSpitzberg
GFSanborn
EMGarcia
MCWilliams, NSIR/DNS/NSO/SOS
GWTuttle NSIR/DNS/NSO/SOS
RLKellar
TKMcLellan, NRR/ADPT/DE/EMCB
WCSifre
KEGardin
FCDB File
SISP Review Complete: EMG
ADAMS: X Yes Initials: emg
X Publicly Available X Non-Sensitive
DOCUMENT NAME: s:\dnms\!fcdb\emg\5050013302 Final: r:\_hb\5050013302
RIV:DNMS:FCDB RIV:DNMS:FCDB NRR:DE:EMCB
EMGarcia RLKellar TKMcLellan
/RA/ via e-mail /RA/ /RA/ via e-mail
08/16/2005 08/17/2005 08/16/2005
RIV:DRS:EB1 NSIR:DNS:SOS NSIR:DNS:SOS NMSS:DWMEP:DD:RDS
WCSifre GWTuttle MCWilliams JBHickman
/RA/ via e-mail /RA/ via e-mail /RA/ via e-mail /RA/ via e-mail
08/16/2005 08/18/2005 08/16/2005 08/16/2005
RIV:ACES C:FCDB D:DNMS
GFSanborn* DBSpitzberg* LDWert
/RA/ /RA/ /RA/
08/16/2005 08/17/2005 08/19/2005
OFFICIAL RECORD COPY T=Telephone E=E-mail F=Fax
- Previous Concurrence
ENCLOSURE
U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Docket No.: 050-00133
License No.: DPR-7
Report No.: 050-00133/05-002
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: November 2, 2004, through August 2, 2005
Inspectors: Emilio M. Garcia, Health Physicist, Team Leader
John B. Hickman, Project Manager, NMSS
Ray L. Kellar, P.E., Health Physicist
Thomas K. McLellan, Materials Inspector, NRR
Glenn W. Tuttle, MC&A Physical Scientist, NSIR
Wayne C. Sifre, Reactor Inspector
Martha C. Williams, Sr. MC&A Physical Scientist, NSIR
Approved By: D. Blair Spitzberg, Ph.D., Chief
Fuel Cycle and Decommissioning Branch
Attachment: Supplemental Inspection Information
ADAMS Entry:IR 05000133-05-02, on 11/02/2004-08/02/2005; Pacific Gas & Electric
Co.; Humboldt Bay, Unit 3. Special Inspection Final Report. Three
apparent violations.
-2-
TABLE OF CONTENTS
EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
REPORT DETAILS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2. Review of PG&Es SNM Control and Accountability Project . . . . . . . . . . . . . . . . . . . . . . 12
3. Material Control and Accounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4. Review of Scenario Involving Fuel Segments Shipped Offsite with Low Level
Radioactive Waste (LLRW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5. Review of Scenario Involving Fuel Segments Shipped Offsite In Other Direct
Shipments (ODS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6. Review of Scenario Involving Incore Detectors Shipped Offsite with Low Level
Radioactive Waste (LLRW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7. Review of Scenario Involving Fuel Segments Stolen or Diverted . . . . . . . . . . . . . . . . . . 32
8. Review of Scenario Involving Fuel Segments Remaining in the SFP in an
Altered Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
9. Cause Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
10. Health and Safety Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
11. Discussion of Previously Identified Unresolved Items and Apparent Violations . . . . . . . 43
12. Licensee Briefings and Exit Interview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
ATTACHMENT - SUPPLEMENTAL INSPECTION INFORMATION:
PARTIAL LIST OF PERSONS CONTACTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
INSPECTION PROCEDURES USED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
ITEMS OPENED, CLOSED, AND DISCUSSED . . . . . . . . . . . . . . . . . . . . . . . 1, 2 and 3
LIST OF ACRONYMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
LIST (Partial) OF SIGNIFICANT DOCUMENTS REVIEWED . . . . . . . . . . . . . . . . . . . . 5
-3-
EXECUTIVE SUMMARY
Humboldt Bay Power Plant, Unit 3
NRC Inspection Report 050-00133/05-002
During the fall of 2003, staff from Pacific Gas and Electric (PG&E) Humboldt Bay Power Plant
were conducting an examination of the contents of its spent fuel pool (SFP). This examination
was in preparation for eventual removal of the fuel for placement into dry storage in an onsite
Independent Spent Fuel Storage Installation (ISFSI). During the sorting of materials in a
container in the SFP, licensee personnel discovered a fragment of a spent fuel rod
approximately 4-inches long. Licensee personnel located additional fuel fragments ranging in
length from 4 to 6 inches in subsequent sorting of materials in the SFP.
The discovery of fuel fragments indicated a potential problem with the Humboldt Bay material
control and accounting (MC&A) practices. In January 2004, during an NRC inspection, the
Plant Manager announced that due to the unexpected presence of the fuel fragments and other
uncertainties in the special nuclear material (SNM) inventory, the licensee initiated a
re-evaluation of the amount of SNM present in each assembly and in the SFP. The NRC
periodically monitored the licensees investigation. In addition, on March 25, 2004, the NRC
conducted a review of practices of spent fuel MC&A at HBPP in accordance with guidance
contained in Temporary Instruction 2515/154, Phases I and II. This Instruction was
implemented to determine if the MC&A issues at Millstone 1 regarding the loss of two spent fuel
rods, are applicable to other power reactors. Based on that review, the NRC decided that
Humboldt Bay required a Phase III inspection under Temporary Instruction 2515/154.
[Completion of Phase III of Temporary Instruction 2515/154 was documented in Inspection
Report Number 50-133/2005-01].
In late June 2004, the licensee found documentation indicating that in 1968 a stainless steel
clad fuel pin from assembly A-49 was segmented into three 18-inch sections. Other records
indicated that the complete A-49 assembly was later shipped offsite for reprocessing. The
licensee promptly informed the NRC of this discovery.
On July 16, 2004, the licensee made formal notification to the NRC pursuant to the
requirements of 10 CFR 20.2201(a)(1)(ii) of the discrepancy between inventory records and the
location of spent fuel pin segments. No records had been found indicating the location of the
fuel segments in the SFP. During July and August 2004, licensee personnel searched the most
likely and accessible locations within the SFP where the fuel segments could be. Region IV
NRC inspectors observed part of the search activities. On August 16, 2004, PG&E issued a 30-
day written followup report to its initial July 16, 2004, notification to the NRC, and the next day
the licensee made a 1-hour notification to the NRC pursuant to 10 CFR 74.11(a) that the
subject fuel pin segments were considered missing.
On September 29, 2004, the NRC held a meeting with licensee management and members of
the public in Eureka, California, to discuss the missing fuel and the licensees planned search
activities. During the public meeting, the NRC Region IV Regional Administrator announced
this special inspection and on October 25, 2004, Region IV established its charter (attached).
On February 22, 2005, the licensee issued their Special Nuclear Material Control and
-4-
Accountability Project Interim Reports (PG&E Interim Reports). On the same date, the licensee
notified NRC (Event Report 41340) and issued License Event Report 2005-01. This notification
and report informed NRC that PG&E was unable to locate one intact in-core detector and three
partial in-core detectors, amounting to less than a gram of SNM.
After the licensee had completed its major search activities for the missing SNM on April 5,
2005, NRC issued Inspection Report Number 50-133/2005-01. This report was an interim
report of the ongoing special inspection. The NRC interim report noted that the Material Control
and Accounting (MC&A) program in place as of November 4, 2004, met regulatory
requirements. However, the interim report also identified four apparent violations concerning
past licensee practices connected with the missing SNM. Three of these apparent violations
are discussed in Sections 3 and 11 of this report. The fourth apparent violation addressed the
possession of SNM in the form of remnants of fuel fragments when neither the license nor the
technical specifications authorized possession of SNM in this form. As noted in Section 11 of
this report, this apparent violation has been resolved and is no longer considered an apparent
violation. The NRC interim report also identified three unresolved items. The unresolved items
are discussed in Section 11 of this report and are considered resolved.
On May 27, 2005, PG&E issued their Special Nuclear Material Control and Accountability
Project Final Report. This report provided the results of the licensees investigation into the
location of the three 18-inch fuel rod segments and missing incore detectors, as well as the
overall control and accountability of SNM at the HBPP. On June 10, 2005, the license
submitted Revision 2 to LER 2004-01, regarding the three missing 18-inch fuel rod segments
and Revision 1 to LER 2005-01, regarding the missing incore detectors.
On June 20-24, 2005, a team of inspectors from NRC Headquarters and Region IV conducted
the final onsite portion of the special inspection to review the licensees efforts to locate the
missing SNM, the licensees scenarios as to the possible locations of the SNM and to complete
the review of current special nuclear material control and accounting practices.
Based on the findings of the special inspection, the inspection team concluded that:
- The licensees current material control and accounting program meets regulatory
requirements. The program had undergone significant changes from that program
described in the interim special inspection report 05000133/2005-001. The changes
made to, and the implementation of procedures for the control and accountability of
SNM, physical inventory, and the use of tamper-indicating devices, had enhanced the
licensees MC&A program (Section 3).
- The licensees SNM Control and Accountability Project which investigated the missing
SNM and the overall control and accountability of SNM at the HBPP was complete and
thorough in its search for the three 18-inch spent fuel segments and missing incore
detectors. The searches included all areas that were reasonable and practical to search
and that could accommodate the fuel segments. The licensee concluded, and the
inspectors agreed, that it is very improbable that the missing SNM could be in an area
not searched. The licensee expects that as the SFP contents are removed for dry fuel
storage, and plant decommissioning progresses, additional fuel fragments may be
found. However, it is very improbable that the intact missing 18-inch fuel segments
-5-
would be found. The inspectors agreed with this assessment (Section 2).
- Although the SNM Control and Accountability Project documentation did not always
include the basis for their conclusions, no instances of erroneous or unreasonable
conclusions were identified (Section 2).
- An Apparent Violation of 10 CFR 74.19(a)(1) was identified for PG&Es failure to keep
records during the period from August 6, 1969, to July 16, 2004, showing the inventory,
transfer or disposal of three approximately 18-inch segments of irradiated fuel
containing approximately 22.5 grams of SNM. Also from June 25, 1973, to February 4,
2005, the licensee failed to keep records, including location and unique identity, showing
the inventory, transfer or disposal of one complete and three partial incore detectors
containing SNM (Sections 3, 11).
- An Apparent Violation of 10 CFR 74.19(b) was identified for PG&Es failure to establish,
maintain, and follow written material control and accounting procedures sufficient to
enable PG&E to account for the SNM in its possession. Specifically, PG&E failed to
account for the SNM contained in three approximately 18-inch segments of irradiated
fuel and one complete and three partial incore detectors (Sections 3, 11).
- An Apparent Violation of 10 CFR 74.19(c) was identified for PG&Es failure to conduct
adequate physical inventories of all SNM in its possession at intervals not exceeding
12 months. Specifically, inventories performed by PG&E from June 4, 1971, to
February 4, 2005, with the exception of periods when the sealed SFP cover was in
place, did not include the three approximately 18-inch segments of irradiated fuel and
one complete and three partial incore detectors (Sections 3, 11).
- The licensee evaluated 258 radioactive waste shipments made to low-level radioactive
waste (LLRW) disposal sites. The inspectors reviewed the screening criteria used by
the licensee and determined them to be reasonable. Of the 258 shipments, 249 were
screened out as implausible leaving 9 potential shipments to be further investigated.
Of the nine potential LLRW shipments, four had been made to Barnwell (South
Carolina) Waste Management Facility and five had been made to US Ecology, Inc.,
(Hanford, Washington) (Section 4).
- The licensees records of LLRW shipments were remarkably thorough, considering the
lack of procedural guidance in effect at the time. The licensees loading procedures for
LLRW shipments lacked guidance for documentation and obtaining a dose rate of
individual items included in the shipments (Section 4).
- The pipe container that had contained the fuel rod segments from assembly A-49 was
never located or described in any LLRW shipment records. In addition, the container
was unlikely to have completely dissolved in the SFP. The inspectors concluded that
the container was more than likely shipped to a LLRW site as irradiated material during
one of the spent fuel pool cleanup campaigns (Sections 4, 8).
-6-
- Using the licensees terminology for the possibility of occurrence, the inspectors
concluded that it was Reasonably Possible that the pipe container along with the fuel
rod segments could have been inadvertently included in a LLRW shipment between
1968 and 1989. This conclusion differs from the licensee determination that it was
Possible, But Not Likely. The LLRW shipments to either Barnwell, South Carolina or
US Ecology in Richland, Washington could have contained the fuel rod segments.
However, the inspectors agreed with the licensees conclusion that the shipments to
Barnwell, South Carolina, that took place during 1983 and 1985, had the highest
probability of containing the fuel rod segments (Section 4).
- The inspectors reviewed the screening criteria and process used by the licensee to
review the Other Direct Shipments (ODS) and determined it was reasonable. The
inspectors agreed with the licensee conclusion that it was Possible, But Not Likely that
the fuel rod segments had been included in an ODS (Section 5).
- The licensee had located an extensive collection of records that documented the history
of the incore detectors at HBPP. A number of shipments of cutup incore segments and
intact incore detectors were documented. The inspectors agreed with the licensees
conclusions that the most likely locations for the missing full and three partial incore
detectors were either the Barnwell or Hanford LLRW disposal facility (Section 6).
- The inspectors agreed with the licensees conclusion that theft or diversion of the three
18-inch fuel rod segments and incore detectors was highly unlikely (Section 7).
- The inspectors concluded that the licensees consultant report performed by ATI to
evaluate the fuel fragments was based on sound engineering judgment and the
consultants were methodical in the process of determining the conditions of the fuel rod
fragments. However, the inspectors concluded that without substantial additional
testing, they could not agree with the ATI consultants conclusion that there was
reasonable evidence that the 18-inch segments maybe among the fragments found in
the SFP (Section 8).
- The NRC teams conclusions differed from the licensees in one notable respect. The
NRC team concluded that the most likely scenario for the missing SNM was that it was
inadvertently shipped to a low level waste burial site. The licensees conclusions
supported this as a possibility, however, its investigation concluded that the most likely
scenario for the missing spent fuel rod segments was that they were still in the spent
fuel pool in an altered condition. The table below compares the inspection teams
conclusions with those of the licensee with respect to the possible scenarios regarding
the missing fuel rod segments and incore detectors:
-7-
Three 18 inch fuel rod segments Incore detectors
Scenario Licensee NRC Licensee NRC
Shipment to LLRW site possible but reasonably reasonably reasonably
not likely possible possible possible
Other Direct shipment possible but possible but highly unlikely highly unlikely
not likely not likely
Theft/Diversion highly unlikely highly unlikely highly unlikely highly unlikely
Still in SFP1 reasonably possible but highly unlikely highly unlikely
possible not likely
1
This scenario includes fuel fragments or incore detectors in the spent fuel pool in either an
altered configuration, or in a location that was not directly observable.
- The cause analysis performed by the licensee followed the applicable procedure and
appeared to be through and adequate. Although the process used by the licensee was
not a root-cause analysis, but a less stringent cause analysis, the inspectors concluded
that the licensee considered all reasonable causes. The identified corrective actions
were complete and comprehensive. The inspectors identified several missed
opportunities to correct the MC&A program to address the three missing approximately
18-inch long fuel fragments and other SNM in its possession (Section 9).
- The inspectors concluded that regardless of whether the missing fuel segments were
located in the SFP, had been shipped to NFS for reprocessing, or had been transferred
to a LLRW disposal facility, the overall risk from the 18-inch fuel rods segments was
minimal to the health and safety of the public, workers, or the environment. Based on
the extremely low risk that the 18-inch fuel rods segments posed, if they were at
Barnwell or Hanford, attempts to locate and retrieve the 18-inch fuel rods segments
would not be justified by arguments concerning public health and safety. The overall
risk from the missing incore detectors, if present (Section 10).
-8-
REPORT DETAILS
1. Introduction
Humboldt Bay Power Plant Unit 3 is currently in decommissioning SAFSTOR1 status. Unit 3
received an operating license from the Atomic Energy Commission2 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 PG&E announced its intention to
decommission the unit based on economic analyses that showed that completing the necessary
seismic upgrades would not be economical. 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 expires on November 9, 2015. The
facility has undergone minimal decommissioning activity since shutdown.
During the fall of 2003, the licensee conducted an examination of the contents of its spent fuel
pool (SFP) in preparation for eventual removal of the remaining fuel assemblies3 to a dry
storage Independent Spent Fuel Storage Installation (ISFSI). On December 15, 2003, PG&E
applied for a license to build an onsite ISFSI.
On November 12, 2003, during sorting of materials in a container in the SFP, licensee
personnel discovered a fragment of a spent fuel rod4 approximately 4 inches long. During
subsequent sorting of materials in the SFP, licensee personnel located an additional eight fuel
fragments ranging in length from 4 to 6 inches. Through record reviews the licensee identified
additional fuel fragments, ranging in length from 1 to 30 inches, that were stored in
one container. These fuel fragments were in addition to those that had been found at that time.
On November 17, 2003, the licensee initially informed NRC personnel by telephone of these
findings. The licensee kept the NRC staff informed of subsequent findings as they arose. In
early December 2003, the licensee stopped additional work with containers in the SFP that
could potentially contain fuel pin fragments until a criticality evaluation could be completed.
The initial fuel assemblies used in 1963 during the first fuel loading were clad with stainless
steel. In 1965, cladding failure of stainless steel clad fuel was observed. In 1966, a fuel
washer was built and used to remove accumulated corrosion on the surface of the fuel pins.
During August through December 1966, fuel inspections identified at least three fuel
1
SAFSTOR is defined as a method of decommissioning in which the nuclear facility is placed and maintained in such
condition that the nuclear facility can be safely stored and subsequently decontaminated (deferred decontamination) to levels that
permit release for unrestricted use.
2
The Atomic Energy Commission was the predecessor to the Nuclear Regulatory Commission.
3
A fuel assembly is a cluster of fuel rods. The HBPP Unit 3 first fuel assemblies were General Electric Type I fuel with
stainless steel cladding and a 7 by 7 fuel rod array for 49 fuel rods per assembly. Forty-eight of the fuel rods had 79 inches active
fuel length and one had an active fuel length of approximately 78.5 inches. The segmented rod in assembly A-49 had an active
fuel length of 79 inches.
4
A fuel pin or fuel rod is a long slender thin walled metal tube that holds fissionable materia (fuel) for nuclear reactor use.
At HBPP Unit 3 the cladding was made of stainless steel or zirconium alloys. The terms pin and rod are used interchangeably.
-9-
assemblies with missing portions of pins. An undated Polaroid photograph of a video monitor
shows an additional assembly, different from those previously identified, with a missing portion
of a pin. Tests performed by licensee personnel demonstrated that all the spent fuel pin
fragments found in the SFP were from stainless steel clad fuel pins. Fuel used after the first
load was made with zirconium alloy. Zirconium alloy cladding was not subject to the same
failures experienced by the stainless steel clad fuel.
During an NRC inspection conducted during January 5-9, 2004, the licensee informed the
inspectors that it had found records that indicated that the stainless steel clad fuel assemblies
were transferred to Nuclear Fuel Services Corporation in West Valley, New York, during the late
1960's and early 1970's. Based on the information found as of the time of the inspection, it was
not clear to the inspectors that the reported transfer of special nuclear material (SNM) would
have accounted for the missing portions of pins. Some assemblies were shipped years after
being inspected and would have been inside containers that would have prevented the damage
from being easily seen. The licensees records indicated that a number of the assemblies in
the pool had pins removed in the 1970's time frame for evaluations by the fuel vendor. It was
not clear to the inspectors if the SNM inventory used by the licensee had accounted for the
removed pins.
On January 9, 2004, during the inspection, the plant manager decided to initiate a re-evaluation
of the amount of SNM present in each assembly and in the SFP. He took this action due to the
many uncertainties in the base inventory. The inspectors opened inspection followup items
(IFIs) 50-133/0304-01 and 50-133/0304-02 to track and review the licensees investigation of
the actions that were taken or should have been taken upon discovery of the fuel fragments;
and re-assessment of the SNM possessed under the license, including the accuracy of special
material status reports previously submitted. The discovery of fuel fragments indicated a
potential problem with the Humboldt Bay material control and accounting (MC&A) practices,
possibly extending as far back as the 1960 time-frame. However, the fuel fragments that were
discovered were contained within the licensees controlled area and did not constitute an
imminent reportability concern due to theft or loss of licensed material in accordance with
requirements of 10 CFR 20.2201 or 74.11.
On March 25, 2004, the NRC conducted a review of MC&A practices for spent fuel at Humboldt
Bay. The review was conducted in accordance with guidance contained in Temporary
Instruction 2515/154. This temporary instruction required the inspector to gather information in
answer to a series of questions about the licensees MC&A program. The questions covered
the following programmatic areas: physical inventory, tracking of individual rods that had been
separated from their assemblies, spent fuel pool practices, written procedures, accounting
records, and visual verification. Based on the responses to the questions, the NRC determined
that this site required additional inspection under the temporary instruction.
On June 29, 2004, the licensee informed NRC staff that it had recently found documentation
indicating that in 1968 a fuel pin was segmented into three 18-inch sections and that other
records indicated that the complete assembly was sent off site for reprocessing.
On June 30, 2004, the licensee convened a Technical Review Group to review the recently
found records. The minutes of an Onsite Review Committee (OSRC) meeting conducted on
October 2, 1968, noted that a fuel rod from assembly A-49 had been cut into three 18-inch long
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segments. These three segments were intended to be sent to Battelle, Ohio, for an
experiment. The minutes indicated that prior to shipment of the rod segments the licensee
learned that the experiment had been canceled and the rod segments were placed in a
container in the pool. Another document from the September - October 1968 time frame
indicated that the rod that had been segmented had been previously damaged while in
operation. This document described a 1.5-inch diameter schedule 40 steel pipe that was used
as a container for the rod segments, which were to be shipped to Battelle. This document also
stated that if possible, the remains of the rod were to be placed in the "garbage can" in the pool.
The garbage can was an aluminum container originally intended for shipping damaged
stainless steel clad assemblies for reprocessing. This container was used for collection of small
irradiated components that were in the SFP. In more recent documents, PG&E has referred to
this container as the central storage container. None of the fuel pin fragments found in
November and December 2003 were 18 inches long.
Other records maintained by the licensee indicated that assembly A-49 was sent to Nuclear
Fuel Services, West Valley, New York, on August 6, 1969, for reprocessing. The record
indicated that the weight of the assembly shipped to Nuclear Fuel Services corresponded with
the weight of the assembly when it was received. Since the OSRC records indicated a fuel pin
had been removed from assembly A-49, the weight on receipt should not have agreed with the
weight on shipment. The licensee decided that this apparent discrepancy constituted a quality
problem related to their SNM records and issued a nonconformance report to address this
matter.
On July 16, 2004, PG&E notified the NRC pursuant to the requirements of
10 CFR 20.2201(a)(1)(ii) of the discrepancy between inventory records and the location of
spent fuel rod segments (Event Notification 40877). No records had been located indicating the
location of the fuel segments in the SFP.
During July and August 2004, licensee personnel searched the most likely and accessible
locations within the SFP where the fuel segments could be physically located. Region IV
inspectors observed part of the search activities, including the opening and removal of contents
from the assembly UD-006N box. On June 4, 1975, zirconium clad fuel assembly UD-006N
was dropped by an operator while being moved from one SFP location to another. As a result,
several rods became separated from the others in the fuel assembly. Subsequently, the
licensee stored all the rods from assembly UD-006N in a box. Some stainless steel clad fuel
fragments were also stored in the UD-006N box. The inspectors observed the search for
assembly A-49 segments in the UD-006 box. Several fragments were found in these searches
that at first appeared to have been cut as opposed to broken due to metal failure. A
metallurgist and a specialist in non-destructive examinations, both employed by the licensee at
their Diablo Canyon Nuclear Plant, examined video images of 12 fragments that initially
appeared to have been cut. The metallurgists opinion was that the video images suggested
that the fragments all exhibit the appearance of a fracture surface and are dark in color as if
oxidized to some degree. This appearance is more typical of inter-granular stress corrosion
cracks that occurred at operating temperature. The non-destructive examination specialist
concurred.
The metallurgist also stated that the schedule 40 steel pipe described in the 1968 records as
the shipping container for the 18-inch segments, could not have completely corroded away.
-11-
The metallurgist stated that even if the pipe container had been made from carbon steel, which
he believed it probably was since the material of construction was referred to simply as "steel
pipe," it would not have completely corroded away. He expected that if it was in the SFP it
would show signs of significant rust and corrosion, possibly even through the wall in localized
areas but it would still be easily recognizable.
On August 16, 2004, PG&E issued a 30-day written followup report to its initial July 16, 2004,
notification to the NRC (Event Notification 40877). This report was made pursuant to
10 CFR 20.2201(b)(2)(ii). The licensee reported implementation of an action plan that included
a detailed physical inspection of the SFP; documentation reviews of PG&E and vendor records;
and interviews with both employees and contractors who had been associated with the
Humboldt Bay SFP and radwaste operations.
On August 17, 2004, the Humboldt Bay Plant Staff Review Committee reviewed the results
from searching the most likely and accessible locations within the SFP where the fuel segments
could be located. During this phase of the search, the missing fuel was not located.
Consequently, the licensee made a 1-hour notification to the NRC pursuant to 10 CFR 74.11(a)
that the subject fuel rod segments were considered missing (Event Notification 40961).
On September 29, 2004, Region IV conducted a public meeting with the licensee in Eureka,
California, to discuss the current and planned search activities. During the public meeting, the
NRC Region IV Regional Administrator announced that a special inspection would be
conducted of the licensees material control and accountability program and that Region IV
would also continue to follow the licensees efforts to search for the missing fuel fragments. On
October 25, 2004, Region IV chartered this special inspection.
On February 22, 2005, the licensee issued their Special Nuclear Material Control and
Accountability Project Interim Reports (PG&E Interim Reports). On the same date the licensee
notified NRC (Event Report 41340) and issued License Event Report 2005-01. This notification
and report informed the NRC that PG&E was unable to locate one intact incore detector and
three partial incore detectors, amounting to less than a gram of SNM.
On April 8, 2005, PG&E submitted the revised ATI report. This licensee consultant report was
titled Evaluation of Nuclear Fuel Rod Fragments and Inference to Fuel Rod A-49 at Humboldt
Bay Power Plant. The executive summary to this report stated, in part, that it was the
judgement of the consultants that there was reasonable evidence that fragments from the three
missing 18-inch segments from assembly A-49 may be among the fuel fragments found in the
SFP.
On May 27, 2005, PG&E issued their Special Nuclear Material Control and Accountability
Project Final Report. This report provided the results of the investigation into the location of the
three 18-inch fuel rod segments and the location of the missing incore detectors, as well as the
overall control and accountability of SNM at HBPP.
On June 10, 2005, the license submitted Revision 2 to LER 2004-01, regarding the three
missing 18-inch fuel rod segments and Revision 1 to LER 2005-01, regarding the missing
incore detectors.
-12-
On June 20-24, 2005, a team of inspectors from NRC Headquarters and Region IV conducted
the final onsite portion of the special inspection to review the licensees efforts to locate the
missing SNM, the licensees scenarios as to the possible locations of the SNM and to complete
the review of current special nuclear material control and accounting practices. This report
documents that effort.
2. Review of PG&Es SNM Control and Accountability Project
2.1 Inspection Scope
The inspectors reviewed the licensees SNM Control and Accountability Project (the
Project) to evaluate the completeness and thoroughness of the search for the three
18-inch spent fuel segments. The review included the search in the SFP and
surrounding areas, the search of historical records, documentation of interviews
conducted with current and former employees and contractors, and the
characterizations of fuel fragments found. This review included project control
documents that consisted of the Project Plan and all Project Instructions, as well as
applicable records generated by the project, video documentation of the search and fuel
fragments characterizations, and the pertinent records obtained by the licensee from
outside PG&E. The inspectors also interviewed the project manager, other key project
personnel, and a former employee and a contractor who had been interviewed as part of
the project.
2.2 Observations and Findings
a. Project Management
The project guidance documents provided adequate and effective guidance for the
investigation process. The investigation method and approach was reasonable and
effective. The investigation had a logical division of investigation paths, inspections,
document reviews & interviews, coordinated with scenario and time line development.
However, although the guidance for control and retention of documents was adequate,
the guidance did not require specific documentation of the basis of decisions.
Consequently, some portions in the report did not have adequate documentation for the
basis of the licensee conclusions. This is discussed in more detail in paragraph f. of this
report section.
b. Records Review
The inspectors reviewed the project control documents including the physical search
data summary document (this document had no revision number or date). The
inspectors also reviewed records obtained from Nuclear Fuel Services (West Valley),
Battelle, and General Electric (GE). The licensees search for and review of records
was well organized, methodical and through. The licensee used a two step process
(designating documents first as applicable, then as relevant) which provided an
independent review. Additionally, the process included a second review audit of
documents determined applicable but then not relevant. This provided a necessary
independent verification of a key decision point. Searches and reviews were conducted
-13-
of both hard copy and electronic media. The documentation of the records review
process was particularly through and complete, including areas that were searched
without results. However, there were significant gaps in the documentation to be
reviewed. This was due to the unavailability of the documents due to their age rather
than a poor search process. Where inconsistencies were identified in the documents,
the SNM project staff resolved them adequately.
The search of records outside the company was adequate given the age of the issue
and the poor filing practices for documents during that time period. Although the
licensee relied on the personnel at the outside facility to conduct the search, there is no
indication the SNM project staff would have been more effective.
The inspectors also reviewed the training program and documentation for the document
readers. The training appeared to be comprehensive, sufficient, and well documented.
A training coordinator was designated and qualified personnel conducted the training on
each project instruction.
c. Physical Search
Inspection Report 05000133/2005-001 describes the observations made by the
inspectors during site visits in November and December 2004 and January 2005.
During these visits the inspectors observed ongoing search activities, including opening
of the UD006N assembly container and the vacuuming of the resin beds. The licensee
had experienced a number of problems that resulted in delays during the search for the
missing segments but the inspectors concluded that regardless of the difficulties
experienced the licensee had conducted a thorough search of the SFP and other areas
of the HBPP outside the SFP that could accommodate the fuel segments and were
probable, e.g. shielded containers or water-filled areas capable of accommodating the
fuel segments. These searches where conducted while maintaining effective personnel
safety. The licensee referred to the systematic searches performed during Phase 2 of
their project as Global Inspection Plan.
The searches did not find the three 18-inch fuel segments in their original form nor the
pipe container in which they were originally stored in 1968. The searches of locations
outside the SFP also did not locate the fuel rod segments, fuel fragments, or any other
irradiated SNM. The searches in the SFP did find fuel fragments, and other irradiated
SNM, including 175 fuel fragments amounting to 282.71 inches in length. The licensee
defined a fuel fragment as a clad or unclad portion of a fuel rod, including pellets or
portions of pellets that have a measurable dimension nominally greater than 1/4 inch.
Cladding without fuel was considered irradiated hardware, not a fuel fragment. The fuel
fragments contains SNM. The Global Inspection Plan also accounted for 50 incore
detectors and identified that one complete and three partial incore detectors were
missing.
The licensee searched all areas that were deemed practical to search and that could
reasonably contain or accommodate the fuel segments. However, these searches did
not include all areas of HBPP, for example the reactor vessel was not searched. The
licensee concluded, and the inspectors agreed, that based on available information it
-14-
was very improbable that the fuel rod segments or fuel fragments could be in any of the
locations not searched. It should be noted that the licensee expects that as the SFP
contents are removed to implement dry fuel storage and plant decommissioning,
additional fuel fragments maybe found. However, if this were to occur it is very
improbable that the intact missing 18-inch fuel segments would be found. The areas
that remain to be searched were too small to contain the intact 18-inch segments or
were recently developed. The area below where the fuel channels were stacked is such
a recently developed area. The channels were placed in their current location in the
year 2000 and no fuel segments or containers were observed when the channels were
stacked. The inspectors agreed that it is possible that additional fragments may be
found but it is very improbable that the intact missing 18-inch fuel segments or the
segments in their shipping container would be found.
d. Interviews
The inspectors reviewed applicable guidance documents including Project Instruction
04, Interviewing, and the results from the different interviews conducted by the
licensee. Additionally, the inspectors interviewed key project personnel. The project
instructions generally provided adequate guidance for an effective controlled interview
process. Although the Phase I interviews were conducted informally, the documentation
was adequate, allowing for the formal interviews to use the Phase I interviews as an
effective starting point. The documentation of the Phase II interviews that were
conducted was adequate. Documentation for why interviews had not been conducted
were not always available or easily recognizable. However, the inspectors determined
that the interviews that had not been conducted were generally not done for good
reasons, i.e. candidate deceased or unable to be located. Additionally, most of the
interviews were conducted by a single interviewer, which could have potentially reduced
the effectiveness of the interview process.
The inspectors conducted two independent interviews with Phase II interview subjects.
These interviews confirmed the records of the Phase II interview, although additional
information was obtained.
e. Fuel Fragment Characterizations
The licensee had used two types of fuels during their operation. The initial fuel load
consisted of fuel clad in stainless steel referred to as Type I. Subsequently, the licensee
used fuel clad with zirconium alloy or Type II fuel. Assembly A-49 from which the
segments were removed was Type I, stainless steel clad fuel. Differences in tube
external diameters, tube wall thickness, and magnetic properties would allow
differentiation between stainless steel and zirconium cladding. The licensee collected a
series of measurements from the fuel fragments with cladding to establish the type of
fuel involved, including external diameters, tube wall thickness, and magnetism. All clad
fuel fragments found were stainless steel clad. The licensee also characterized each
fragment found by measuring the length of fuel and the dose rates at nominal contact
(approximately 1 cm from center of detector) and at 6 inches. The inspectors observed
portions of the licensees activities to measure, identify, characterize, and store fuel
fragments.
-15-
Using information known about the missing 18-inch segments, the licensee calculated
the estimated dose rates and reported this information in Licensee Event Report
(LER) 2004-001, revisions 0 and 1. The NRCs Special Inspection Interim report
05000133/2005-001 noted that the calculated dose rates were at least 10 times greater
than the measured dose rates in fragments that had been found. The licensee agreed
to review their calculation for possible errors.
Revision 2 to LER 2004-001, issued on June 10, 2005, revised the calculated dose
rates. A footnote to Table 3, Calculated Dose Rates, of the revised LER stated that the
dose rates in this table were corrected from the previous LER revision, as described in
PG&E Calculation NX-289. Revision 3 to PG&E Calculation NX-289 noted that the
initial calculations were performed using the power level that corresponded to the power
generated in three segments (54 inches) of fuel rod. The revision used the power level
for one 18-inch segment. These calculated dose rates were still at least twice the
values measured.
To address this apparent discrepancy the licensee performed PG&E Calculation
NX-293. This calculation evaluated the underwater dose rates postulated from the A-49
18-inch segments, at multiple distance from the segment, including 1 centimeter and
6 inches. This calculation also estimated dose rates from fragments of 1, 2, 3, 6, 9, and
12 inches in length. The calculation also estimated dose rates for various burnup rates
of the fragments. The table below compares the measured dose rates for selected
fragments to the calculated values at 1 centimeter and 6 inches using the burnup rate of
13,000 megawatt-day per metric ton uranium (MWD/MTU). The calculated values at
1 centimeter range from two to four times the measured values. At 6 inches the values
are in better agreement ranging from comparable to three times the measured value.
The inspectors concluded that when comparing the calculated dose rates for the A-49
segments to the measured dose rates on the fuel fragments in the SFP it is not
reasonable to conclude that any of the fragments of interest originated from assembly
A-49.
-16-
Table 1
Humboldt Bay Power Plant Unit 3
Measure vs Calculated Dose Rate for Fuel Fragments
Fragment Fuel Length Measured Calculated Rate Approximate
in Inches Rate in R/hr in R/hri (NX-293) Ratios Calc/Meas
1 cm 6" 1 cm 6" 1 cm 6"
FF013 2e 230 9 701 10 3 1
FF021 13 d 198 10 776 29 4 3
FF026 10 209 7.5 774 25 4 3
FF027 6d 303 15 762 18 3 1
FF029 1 101 1.3 431 3 4 2
FF030 41/2 325 7 701 10 2 1
FF031 23/4 216 4.5 701 10 3 2
FF033 3.5 275 5 701 10 3 2
FFO34 3c 271 4 701 10 3 3
Ii
Calculation NX-293 calculated dose rates for fragments of 1, 2, 3, 6, 9, 12, and 18 inches in length. The recorded dose
rates are for the nearest calculated value to the measured fuel length, and for a burnup rate of 13000 MWD/MTU.
f. Documentation of Investigation
The inspectors reviewed the project documentation in support of the final report.
Although the documentation was generally adequate to support the conclusions of the
final report, one notable exception was the basis for decisions. Although the inspectors
were able to reconstruct the basis by examining supporting documentation, the basis for
some decisions was not explicitly provided in the report. Examples include:
- No documentation was provided for the individuals listed on the proposed
interview list who were not interviewed, other than for those individuals who were
determined to be deceased. Although the basis could be determined by the
inspectors, it had not been documented by the SNM Project.
- No documentation was provided for the basis of the Other Direct Shipments
which were excluded from further consideration. Again, the inspectors were able
to determine the basis and have no issues with the basis, but it was not provided
in the SNM Project documents.
- Calculations were not performed to support the licensees conclusion that the
area radiation monitors (ARMs) would have alarmed if the rod segments had
been removed from the spent fuel pool. Although these calculations were
performed and provided during the course of the inspection, they were not
provided in the SNM Project documents.
-17-
Although the SNM Project documentation did not always document the basis of the
conclusions, no instances of erroneous or unreasonable conclusions were identified.
g. Adequacy of Interfaces with Government Agencies (NRC & States)
The inspectors reviewed the contact list for the fuel issue and interviewed key licensee
personnel. The contact list of government contacts was maintained current and tracked
for each notification. The notifications were timely. A weekly status call (subsequently
changed to bi-weekly at the participants request) was conducted with key stakeholders.
The contact list for significant updates was tracked by the licensees public affairs staff.
Additionally, the existing citizens advisory board, which includes local government
officials, was kept informed of the progress of the investigation.
2.3 Conclusions
The licensees SNM Control and Accountability Project was complete and thorough in its
search for the three 18-inch spent fuel segments and missing incore detectors. The
searches included all areas that were reasonable and practical to search and that could
accommodate the fuel segments. The licensee concluded and the inspectors agreed
that it is very improbable that the missing SNM could be in any of the locations not
searched (e.g. the reactor vessel). The licensee expects that as the SFP contents are
removed for fuel dry storage and plant decommissioning, additional fuel fragments may
be found, but that it is very improbable that the intact missing 18-inch fuel segments
would be found. The inspectors agreed with this assessment.
By comparing the measured dose rates on the fuel fragments in the spent fuel pool to
the calculated dose rates for the A-49 segments, the inspectors could not associate any
of the candidate fragments with those originating from assembly A-49.
Although the SNM Control and Accountability Project documentation did not always
document the basis for their conclusions, no instances of erroneous or unreasonable
conclusions were identified.
3. Material Control and Accounting
3.1 Inspection Scope
The inspectors reviewed changes made to the licensees Material Control and
Accounting (MC&A) program since the special inspection visit in November 2004 (see
inspection report 05000133/2005001). The inspectors reviewed the licensees written
MC&A procedures, which addressed control and accountability of SNM, physical
inventory, and the use of tamper-indicating devices. The inspectors interviewed
personnel on procedure implementation and examined records generated by the
procedures.
3.2 Observations and Findings
The over-arching material control and accounting procedure in force at the time of the
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inspection was HBAP D-7, Control and Accountability of Special Nuclear Material and
Waste Shipment, Volume 1, Revision 11, dated May 2, 2005. The procedure defined
MC&A roles and responsibilities; provided instructions for identification, shipment, and
transfer of SNM; provided instructions concerning the discovery of SNM-containing
articles or SNM waste; and described the records and reports used to control and
account for SNM.
Several definitions were added to the procedure to better classify the various forms of
SNM in the SFP. New sections were added to provide more detail on SNM
Accountability Records and the discovery of SNM-containing articles or SNM waste.
The SNM Accountability Record form, SNM Movement Authorization form, and the SFP
map were revised to provide more thorough entries on the forms, to enhance
traceability, to provide better control of SNM moves, and to enhance the process of
updating records.
The inspectors reviewed the recently created accountability records for the new SNM
containers - SC1, FUEL FRAG, and UFFC. The forms included the serial number of the
Tamper Indicating Device (TID) installed and a reference to the container contents as
required by HBAP D-7. The inspectors also reviewed the accountability records for a
sample of assemblies and verified that attachments were added describing the history of
the assembly as specified in HBAP D-7.
The inspectors reviewed the licensees physical inventory procedure STP 3.6.6, SNM
Inventory, Volume 6, Revision 20, dated May 2, 2005. Steps were added to verify that
all SNM-containing items listed in the accountability records are found in the SFP and to
visually inspect the TID tags installed on the SNM storage containers. The inspectors
reviewed the SFP map from the most recent inventory conducted on May 5, 2005, and
reviewed a sample of 30 assembly accountability records to verify that the locations of
the assemblies as indicated on the SFP map matched the location in the accountability
records. The new SFP map and all reviewed accountability records were completed
according to procedure. The TID serial numbers for the SNM containers were verified
as required during the inventory.
The inspectors reviewed procedure HBAP D-8, SFP Cover Seals and SNM Container
TIDs, Volume 1, Revision 0, dated May 2, 2005. This new procedure included the
requirements for installation and removal of the SNM storage container TIDs. The
inspectors observed the new TIDs on the storage containers via underwater camera
while inspecting the SFP, and viewed video and photographs of the installation of the
TIDs. As mentioned above, the inspectors verified that the TID serial numbers were
recorded on the accountability records for the storage containers, and were verified at
the most recent inventory, as required.
On August 6, 1969, assembly A-49 was shipped off site for reprocessing, from that date
forward, PG&E failed to maintain records indicating whether the three approximately
1-inch long segments of irradiated fuel were in their inventory, had been transferred or
had been disposed. Calculations made by the licensee indicate the three segments
contained approximately 22.5 grams of SNM.
-19-
Site records indicated that during the period of June 21 to 25, 1973, some incore strings
were cut to remove the incore detectors . The incore detectors from three selected
incore strings were then transferred to another licensee on June 25, 1973. An additional
nine incore strings were presumed to have been cut and segmented during this same
time frame, based on plant documentation. Evidence indicated that several segments
from the incore cutup operations conducted during 1973 were approximately 30 inches
in length. The three partial incore detectors were found in segments that were also
approximately 30 inches long. June 1973 is the most likely period when control and
accounting of the SNM in the incore detectors was lost, since the licensee did not know
which lengths of incore string tubing contained SNM and which were just irradiated
hardware. The inspectors concluded that this is when the licensee lost control of the
accounting for the SNM in the incore detectors.
Records maintained by the licensee indicated that on June 4, 1971, the last shipment of
fuel with stainless steel cladding, also known as Type 1 fuel, was made. At that point
the licensee removed all the associated SNM contained in the Type 1 fuel from their
inventory. However, as noted on the licensees calculation NX-288, over the last year
and half, the licensee has found 175 Type 1 fuel fragments. These fuel fragments are
the equivalent to more than 280 inches of fuel or more than the equivalent of three fuel
rods. In calculation NX-290, the licensee calculated that as of September 30, 2004, this
amounted to 97 grams of uranium-235 and 22 grams of plutonium. Additionally,
licensees calculation NX-290 also estimated that there was 10 grams of uranium-235
and 5 grams of plutonium as SNM waste in the SFP. Regulations in effect during these
time frames required that inventories account for all SNM, including the amount
contained in the fuel fragments.
Even though the presence of Type 1 fuel fragments was noted during the 1976 and the
mid-1980's pool clean up campaigns and the licensee conducted SNM inventories at the
required intervals, these inventories failed to account for the SNM in the fuel fragments
and SNM waste. Inventories of all SNM have been required by applicable regulations
throughout this time.
These failures in the SNM control and accountability program were noted in the interim
inspection report and are identified as apparent violations on Section 11 of this report.
3.3 Conclusions
The inspectors concluded that the licensees current material control and accounting
program meets regulatory requirements. The program has undergone significant
changes from that program described in the special inspection report
05000133/2005-001. The changes made to, and the implementation of, procedures for
the control and accountability of SNM, physical inventory, and the use of tamper-
indicating devices, have enhanced the licensees MC&A program.
-20-
4. Review of Scenario Involving Fuel Segments Shipped Offsite with Low Level
Radioactive Waste (LLRW)
4.1 Inspection Scope
The inspectors reviewed the licensee screening process that was used to evaluate the
potential inclusion of the three fuel rod segments in LLRW shipments. Supporting
shipment records and plant procedures that were used for LLRW shipments were also
reviewed.
4.2 Observations and Findings
This scenario evaluated the possibility that the three missing spent fuel rod segments
were inadvertently included in a LLRW shipment, that would have originated from HBPP
between September 1968 and July 1989. This scenario assumed that the three 18-inch
fuel rod segments would not have been recognized as spent fuel and were either
individually or collectively included with other radioactive waste and shipped offsite.
Portions of the screening process used by the licensee for LLRW also evaluated the
potential that the three fuel rod segments were included in what the licensee termed
Other Direct Shipments (ODS). A separate scenario will be evaluated for ODS.
The licensee investigation for the both the LLRW and ODS scenarios started with a
record review to locate all the radioactive material shipment records. After the
radioactive material shipment records were located, they were screened for applicability
and relevancy by the licensee using instructions contained in procedure Special
Nuclear Material (SNM) Inventory, Inspection & Control Project, Project Instruction
Documentation Investigation SAP8065936 - PI - 03, Revision 5, dated March 18, 2005.
The licensee then evaluated all of the 490 radioactive material shipment records that
had been determined to be applicable and relevant by using the Screening Tool for
Fuel Rod Segments in Offsite Shipments, approved May 24, 2005. This screening tool
provided detailed criteria for evaluation of the potential inclusion of the spent fuel rod
segment(s) in either LLRW shipments or in ODS.
The Screening Tool for Fuel Rod Segments included potential scenarios explaining how
the fuel rod segments could have been inadvertently shipped from the site along with
evaluation criteria to determine if the fuel rod segment(s) were contained within a
shipment. Each shipment was conservatively evaluated using the radiological dose
profile from a single fuel rod segment. Table 3.1-1 of the Screening Tool for Fuel Rod
Segments provided a summary of the evaluation criteria that was used by the licensee
to determine whether the shipment could contain the missing fuel segments. The
criteria from Table 3.1-1 utilized to evaluate the shipping records consisted of:
5. The first screening criteria that was considered in the process determined if the
shipment of radioactive material had been receipt inspected upon arrival at the
final destination. The licensee evaluated the plausibility of a material recipient
inspection occurring that would have recognized the presence of the fuel rod
segments as an anomaly and contacted HBPP personnel. Material contained in
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LLRW shipments were not individually receipt inspected and therefore received
further consideration.
6. The second screening criteria considered the dose rate of the package. If the
shipment had a high dose rate, the presence of the fuel rod segments were
more plausible. A dose rate tool contained in Humboldt Bay Power Plant
Calculation No. NX-292, Revision 1, provided several dose rate versus decay
time curves for different types and sizes of transportation packages. The
package types evaluated by the curves included large Low Specific Activity
(LSA) boxes, small LSA boxes, steel drums and cardboard boxes. The dose
rate associated with a single 18-inch segment was conservatively applied in each
of the curves. If the dose rate of the individual package was above the
calculated dose rate curve from Calculation No. NX-292, the package would be
further evaluated.
7. The third screening criteria determined if the shipment used a shielded cask.
The shielding provided by the cask made it more plausible that the presence of a
fuel rod segment would be undetected during radiation surveys. A package that
was shielded would receive additional evaluation. Even if the package was not
shielded, it was still evaluated utilizing the dose rate versus decay time curves
from Calculation No. NX-292.
8. The forth screening criteria examined the contents and details of the shipping
manifest. The shipping records were reviewed to determine if the description of
the package contents described items with a similar appearance and/or
configuration to the fuel rod segments or pipe container.
9. The fifth screening criteria determined if the material originated from the spent
fuel pool. Due to the extremely high dose rates emitted from the fuel rod
segments, their most probable storage location would be under water in the
spent fuel pool, where they were initially placed in 1968. It was considered
highly unlikely that the fuel rod segments would have been moved from the spent
fuel pool during the course of normal operations, due to the extremely high dose
rates involved with their movement. A planned movement of the fuel rod
segments should have required additional documentation and procedures, which
were not located during the record search.
10. The sixth screening criteria considered whether the package involved the
solidification of an ion exchange resin or a concentrated liquid. Requirements for
processing a liquid or a resin for waste shipment were considerably different
than those associated with preparing a solid item for shipment, such as a pipe.
Regulations also prohibited mixing waste forms and therefore, packages that
contained resin or liquids were not evaluated further.
11. The seventh and final screening criteria confirmed that the date associated with
the shipment record occurred after the segments had last been documented to
be located in the spent fuel pool in 1968 and before the pool cover was installed
in 1989. The segments could not have been shipped offsite prior to their initial
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placement in the spent fuel pool in September 1968 and there were no
shipments that originated from the spent fuel pool, exceeding the dose rate
screening criteria contained in Calculation No. NX-292, after the pool cover had
been installed in July 1989.
The licensee utilized the screening criteria listed above, although not necessarily in the
order listed, to examine and evaluate if the fuel rod segments and/or the pipe container
could have been removed and shipped from the site to a LLRW or ODS facility.
The inspectors concurred that the Screening Tool for Fuel Rod Segments and the
screening process utilized by the licensee to evaluate LLRW shipments and ODS was
appropriate.
The inspectors selected 30 of the ODS and LLRW shipments that had been screened
by the licensee for an independent review. Selected records of shipments to General
Electric Co. Vallecitos, CA; Nuclear Fuel Services; Nuclear Engineering Co., Richland,
WA; Nuclear Engineering Co., Beatty, NV; Southwest Radiological Health Lab and
US Ecology were compared to the screening results obtained by the licensee using the
Screening Tool for Fuel Rod Segments in Offsite Shipments. No deficiencies of the
licensee screening results were identified.
Utilizing the Screening Tool for Fuel Rod Segments, the licensee evaluated 258
radioactive shipments made to LLRW facilities. Of these 258 shipments, 249 were
screened out as implausible based on the criteria mentioned above. There were nine
potential LLRW shipments that were determined to be candidates for the inadvertent
shipment of the fuel rod segments. The potential LLRW shipments included four to
Barnwell Waste Management Facility located in Barnwell, South Carolina and five to
US Ecology, Inc., located in Richland, Washington. The LLRW shipments were made in
two phases. The initial phase consisted of three shipments to Barnwell Waste
Management Facility during 1983. The second phase consisted of one shipment to
Barnwell and five shipments to US Ecology, Inc., during 1985 and 1986.
The first three shipments to Barnwell Waste Management Facility occurred during
October and November 1983. The first shipment record was dated October 11, 1983,
and described the waste contents as reactor control rods, control rod followers and
poison curtains.
description of small material or miscellaneous parts was not included with the first
shipment record. This could mean that no additional material was necessary to stabilize
the shipment or that a detailed list of the items had been omitted. The second shipment
record dated October 24, 1983, and the third shipment record dated November 16,
1983, described the waste contents as reactor control rods, control rod followers,
poison curtains, fuel channels & misc. parts. Handwritten descriptions of the items
included in the waste shipments as shoring or misc. parts along with sketches of the
articles were located with the records for both the second and third shipments. None of
the items that were described or sketched included with the second or third shipments
resembled the fuel rod segment pipe container or the fuel rod segments. Dose rate
surveys had not been performed on the individual items included as shoring in the
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shipments. Dose rate readings were performed after all the waste had been placed in
the liners for shipment, while still underwater in the spent fuel pool. Due to the highly
radiated components that were included in the waste shipments, the dose rate readings
measured underwater for the three Barnwell shipments varied from 600 to 2,200 Rem
per hour. Therefore, final dose rate surveys performed for these shipment packages to
Barnwell would have masked the presence of the fuel rod segments, if they had been
present.
The loading of the radioactive material into the LLRW shipment casks for the 1983
Barnwell shipments was reported to have been performed by HBPP personnel. Chem-
Nuclear Systems, Inc., personnel provided the personnel and equipment to ship the
transportation packages from HBPP to the LLRW disposal site. Temporary Procedure
No. 10/04/83, Loading the Shipping Cask Liner, Revision 100-10/83, had been utilized
to perform the loading operations for the cask liners. Procedure step number 10.f.
stated, Load any more items that will fit in the available space. Load items in the
remaining space in the top of the liner as directed. Therefore, the temporary procedure
directed the loading personnel to place as many items as possible into the available
spaces in the transportation cask. The temporary procedure did not require individual
items be listed or surveyed as they were incorporated into the waste shipments.
A major change to the regulations for radiological waste shipments occurred in
December 1983. This was when the requirements of 10 CFR Part 61, Licensing
Requirements for Land Disposal of Radioactive Waste became effective.
10 CFR Part 61 required, in part, that the waste be properly classified and packaged in
such a manner to provide structural stability of the waste at the disposal site. Prior to
implementation of this regulation, the requirements for classification of items included in
a waste shipment were less stringent.
The second phase of LLRW shipments consisted of one shipment to Barnwell Waste
Management during the last quarter of 1985 and five shipments to US Ecology during
the first quarter of 1986. These shipments were all made after 10 CFR Part 61
regulations went into effect. In contrast to the earlier LLRW shipments made during
1983, Chem-Nuclear Systems, Inc., personnel loaded all the shipments.
The fourth LLRW shipment to Barnwell Waste Management Facility occurred on
December 15, 1985. The radioactive waste shipment manifest described the waste as
activated metal. A handwritten spreadsheet included with the records listed the
dimensions, weight and average dose rates for each individual item. The item
descriptions did not resemble the fuel rod segment pipe container or the fuel rod
segments. Dose rate information was provided for the individual items, but high dose
rate readings would have masked the presence of the fuel rod segments. The
radioactive waste shipment record reported that 1,520 linear inches of cutup incore tube
string pieces or processed incores were included. The average radiological dose rates
for the processed incores were recorded as 69.3, 218.83 and 145.36 Rem per hour.
The processed incores were reported to consist of various lengths of incore pieces,
that were composed of stainless steel tubes with a diameter of 0.75 inches. The
missing fuel rod segments also consisted of stainless steel tubes, approximately
18 inches long and were 0.50 inches in diameter. It is not known whether the missing
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fuel rod segments were ever removed from the pipe container. A HBPP Memorandum
to File, dated February 24, 1986, stated that additional pieces of the cutup incore tubes
had been located during subsequent pool cleanup work. From this statement, it could
be concluded that during previous incore tube cut-up campaigns, portions of the tubes
had been misplaced in the spent fuel pool and later recovered. It is reasonable to
assume that if the fuel rod segments had become separated from the pipe container,
they could have been mistaken as previously cut-up incore tubes. The small difference
in stainless steel tube diameters between the fuel rod segments and the incore tubes
would have been difficult to differentiate underwater in the spent fuel pool. However, the
inclusion of the fuel rod segments was believed to be highly unlikely due to
documentation included in the HBPP Memorandum to File, dated February 24, 1986.
Information in the memorandum indicated that only the incore segments that had been
cut up during the year 1985 were included in the shipment. Therefore, only a small
potential for the inclusion of miscellaneous incore pieces found on the bottom of the
spent fuel pool would have existed.
five shipments to US Ecology in Richland, Washington occurred on January 20,
1986; January 28, 1986; February 5, 1986; February 18, 1986 and March 4, 1986. Each
of the five shipment manifest records described the waste as metal oxides and
plastic/cellulose filter media, stabilized/encapsulated in cement. A separate
handwritten sheet of paper found with each of the 5 waste shipments provided a
description for each item that had been included in the shipment. Additionally, the
weights and average dose rates for each item were also included on the handwritten
sheets of paper. The descriptions of the items included in the shipments did not
resemble the fuel rod segment container nor the fuel rod segments, however some of
the item descriptions were of 55 gallon drums that could have contained the missing
items. An example of such a container would be the shipment that occurred on
January 28, 1996, that included a drum containing compacted spent fuel pool trash.
Dose rate information was provided for the individual items in the radwaste shipment,
but high dose rate readings of the packages varied from 13 to 30 Rem per hour and
would have masked the presence of the fuel rod segments.
Instructions for loading the radioactive waste shipment liners during the 1985 and 1986
shipment campaigns were included in Temporary Procedure No. 12/26/85 No. 2,
Loading SFP Hardware into Chem-Nuclear Systems CNS 8-120 Liner and Cask,
Revision 146-12/85. Step 8 of the Temporary Procedure stated, Liner is now ready to
be loaded with hardware as approved by Chem-Nuclear personnel with the concurrence
of the PGandE Chemical/Radiation Protection Engineer. The step is very vague by
todays standards and does not preclude the undocumented introduction of additional
items into the liner nor does the procedure require that each item receive a dose rate
survey. However, a dose rate survey of each major item was located with the records
for each shipment. Figure 1 of the Temporary Procedure contained the only
procedurally required dose rate readings, that specified final dose rate readings be
taken and recorded at 32 separate locations on the liner after loading operations had
been completed.
The inspectors conducted a telephonic interview with an individual that had served in a
supervisory capacity with Chem-Nuclear Systems, Inc., during the LLRW shipments
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conducted during the years 1985 and 1986. The individual described the process of
documenting and obtaining a dose rate survey for each item included in the LLRW
shipment. The process details described by the individual closely aligned with the
details contained in the LLRW shipment records, recovered by the licensee.
The licensees records of LLRW shipments were remarkably thorough, considering the
lack of procedural guidance and regulatory requirements. The licensees loading
procedures for LLRW shipments lacked guidance for documentation and obtaining a
dose rate of individual items in the shipment. The licensee procedures did not require
that a closed container, such as a pipe, be opened to evaluate the container contents.
The licensee did not have a current procedure that could be used to ship LLRW in a
shielded cask that originated from the spent fuel pool.
There were no items discovered during the licensees review of LLRW shipment records
that matched or resembled the pipe container that had contained the fuel rod segments.
Unfortunately, the only record located by the licensee described the pipe container as
1 1/2" schedule 40 steel pipe. Regardless of whether the pipe was made from carbon
steel or stainless steel, a substantial portion of the pipe along with the pipe caps were
expected to have remained intact in the spent fuel pool. Since the pipe container was
not located in the spent fuel pool and no records exist that indicated a planned or
procedural approved movement of the pipe container with the fuel rod segments ever
occurred, it is possible that the pipe was disposed of as radwaste with or without the fuel
rod segments inside.
4.3 Conclusions
The inspectors reviewed the screening criteria used by the licensee and determined that
the process utilized to evaluate and screen the LLRW shipments was reasonable.
The licensee evaluated 258 radioactive waste shipments made to low-level radioactive
waste (LLRW) disposal sites utilizing the Screening Tool for Fuel Rod Segments. Of
these 258 shipments, 249 were screened out as implausible leaving 9 potential
shipments to be further investigated. Of the nine potential LLRW shipments, four had
been made to Barnwell (South Carolina) Waste Management Facility and five had been
made to US Ecology, Inc., (Hanford, Washington).
The first three shipments to Barnwell had been loaded by Humboldt Bay personnel
during 1983. Handwritten records provided descriptions of the small items included in
the last two radwaste shipments, but a description was missing from the first radwaste
shipment. Site procedures governing loading activities lacked instructions to describe
and document items included in the radwaste shipment and specifically directed loading
personnel to fill available spaces in the liner with waste items.
The fourth Barnwell shipment had been loaded by Chem-Nuclear personnel during the
1985 time frame. A handwritten record confirmed that the shipment contained
processed incores. The fuel rod segments could have been mistaken as cutup incore
-26-
string tubes and included in the shipment. However, this was believed to be highly
unlikely. The high dose rates associated with the incore string tubes would have
masked the missing fuel rod segments, if they had been present.
The five shipments to US Ecology in Richland, Washington were loaded and shipped by
Chem-Nuclear personnel during the 1986 time frame. Handwritten records were
available that provided descriptions of items included with the shipment together with
dose rates for the individual items. The procedural instructions to document individual
items placed in the radwaste shipments were vague.
The licensees records of LLRW shipments were remarkably thorough, considering the
lack of procedural guidance and regulatory requirements. The licensees loading
procedures for LLRW shipments lacked guidance for documentation and obtaining a
dose rate of individual items included in the shipments.
The pipe that had contained the fuel rod segments was never located or described in
any LLRW shipment records. Since the pipe container was never located, it was
plausible that it had been shipped from the site as radwaste during one of the spent fuel
pool cleanup campaigns.
Using the licensees terminology for the possibility of occurrence, the inspectors
concluded that it was Reasonably Possible that the pipe container along with the fuel
rod segments could have been inadvertently included in a LLRW shipment between
1968 and 1989. This conclusion differs from the licensee determination that it was
Possible, But Not Likely. The LLRW shipments to either Barnwell, South Carolina or
US Ecology in Richland, Washington, could have contained the fuel rod segments.
However, the inspectors agreed with the licensees conclusion that the shipments to
Barnwell, South Carolina, that took place during 1983 and 1985 had the highest
probability of containing the fuel rod segments.
5. Review of Scenario Involving Fuel Segments Shipped Offsite In Other Direct
Shipments (ODS)
5.1 Inspection Scope
The inspectors reviewed the license screening process used to evaluate the potential
inclusion of the three spent fuel rod segments in Other Direct Shipments (ODS) that
contained radioactive material. Shipment records and other supporting documentation
for the ODS were also reviewed.
5.2 Observations and Findings
This scenario evaluated the inadvertent inclusion of the three missing spent fuel rod
segments in a shipment classified as ODS. An ODS is defined as a radioactive
materials shipment that was made from HBPP to another licensee authorized to receive
the shipment. The ODS shipments differed from LLRW shipments in that the
radioactive material that was shipped was not waste. The radioactive material would be
utilized or processed by the licensee, normally expected to include unpacking, receipt
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inspection and handling of the material. This scenario assumed that the three 18-inch
fuel rod segments would have been recognized as an anomaly and the licensee would
have then contacted HBPP personnel.
The licensee used several of the same processes to evaluate this scenario that were
used to determine if the segments were contained in a LLRW shipment. The
radioactive shipment records were screened for applicability and relevancy. The
licensee then applied the screening criteria from Table 3.1-1 of the Screening Tool for
Fuel Rod Segments to evaluate the potential for inadvertent inclusion of the fuel rod
segments into one of the ODS.
The inspectors selected and reviewed 30 of the ODS and LLRW shipments that had
been screened by the licensee. No deficiencies of the licensee screening results were
identified.
Utilizing the Screening Tool for Fuel Rod Segments, the licensee evaluated 232
radioactive ODS. Of these 232 shipments, 217 were screened out as implausible.
The 15 ODS that were screened in as potential candidates for receipt of the fuel rod
segments were the shipments of fuel for reprocessing to Nuclear Fuel Services (NFS) at
West Valley, New York.
The 15 ODS shipments of irradiated spent fuel assemblies were made to NFS between
May 14, 1969, and June 3, 1971. Each of the shipments were reported to contain 18
fuel assemblies. Interviews with plant personnel indicated that it would have been
possible to include the fuel rod segments and pipe container in the fuel shipment cask.
However, due to the level of difficulty necessary to accomplish this task, documentation
would most likely have included in a plant record. A record that indicated the fuel rod
segments had been placed in a shipping cask with the fuel assemblies was never
located.
The spent fuel reprocessing activities at NFS were described in a report by Nuclear
Audit and Testing Company entitled, Surveillance of Humboldt Bay Spent Fuel During
Reprocessing at the NFS at West Valley, New York, dated October 25, 1971.
The focus of the report was on accounting for the percentages of uranium and
plutonium that had been recovered during fuel reprocessing. The radionuclides from the
assemblies were reclaimed in batches of 11 fuel assemblies. The report specified that
fuel assembly A-49 had been included in Dissolver Batch number 8 and Tank 3D-1
batch number 13. The report documented the variance between the recorded weights
of the uranium and plutonium that were recovered from the batch of fuel assemblies that
contained assembly A-49, as well as the other batches of fuel assemblies received from
HBPP. The nuclide variances of the individual batches far exceeded the radionuclide
weights reported in the three fuel rod segments by the licensee in Licensee Event
Report 2004-001-002. Therefore, accounting records of reclaimed radionuclides, that
could have indirectly substantiated the presence or absence of the missing fuel rod
segments were inconclusive due to large variances.
The licensee requested three of the most likely ODS recipients to perform a search to
determine if their records indicated receipt of the fuel rod segments or the pipe
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container. Responses were received from New York State Energy Research and
Development Authority (formerly NFS), dated September 10, 2004; Battelle, dated
September 8, 2004; and General Electric, Vallecitos Nuclear Center, dated October 14,
2004. New York State Energy Research and Development Authority responded that a
review of available records did not disclose any information of the receipt of a small
shipping container with fuel rods or of the disposition of the three rod segments.
Battelle reviewed its records and confirmed that the planned shipment of the three
irradiated fuel rod segments from HBPP to Battelles West Jefferson, Ohio facility did
not take place. General Electric responded that after an extensive review of available
General Electric records, they did not identify any information to support a finding that
the three unaccounted for Humboldt Bay fuel rod segments were ever received at the
GE Vallecitos Nuclear Center or the GE San Jose facilities.
The shipment records reviewed by the inspectors normally contained detailed
descriptions of the individual items included in the shipments. Based on a review of the
available information, the inspectors agreed with the licensee conclusion that it was
Possible, But Not Likely that the fuel rod segments had been included in an ODS.
5.3 Conclusions
The inspectors reviewed the screening criteria used by the licensee and determined that
the process utilized to evaluate and screen the Other Direct Shipments (ODS) was
reasonable.
The licensee evaluated 232 radioactive ODS made to other licensees using the
Screening Tool for Fuel Rod Segments. Of these 232 shipments, 217 were screened
out as implausible leaving 15 potential shipments of irradiated fuel to NFS for
reprocessing to be further investigated.
No conclusive or circumstantial evidence was found to support the premise that the fuel
rod segments were included in an ODS.
The inspectors agreed with the licensee conclusion that it was Possible, But Not Likely
that the fuel rod segments had been included in an ODS.
6. Review of Scenario Involving Incore Detectors Shipped Offsite with Low Level
Radioactive Waste (LLRW)
6.1 Inspection Scope
The inspectors reviewed licensee documents consisting of incore accountability records,
shipment records, procedures and miscellaneous correspondence to determine if the
incore detectors had been shipped offsite with a LLRW shipment.
6.2 Observations and Findings
This scenario evaluated the possibility that the one full and three partial missing incore
detectors, also called ion chambers, were included with a LLRW shipment. The
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licensee reported their belief that the missing incore detectors had been erroneously
included with irradiated hardware and shipped to a LLRW facility at Hanford or Barnwell,
in Licensee Event Report 2005-001-01. The inspectors independently reviewed
available documents to determine the most likely location of the missing incore
detectors including the accounting of the incore detector string segments. This scenario
concentrated on the incore detector strings that had been placed in the spent fuel pool
and later cutup and was not concerned with the intact incore detector strings that have
not been irradiated.
A brief description of the incore detector string composition and the process used to
cutup the incore detector strings for shipment follows. Each incore detector string,
hereafter referred to as simply an incore, consisted of a stainless steel tube
approximately 16-feet long with three incore detectors, also called ion chambers. Each
incore detector contained a small amount of Special Nuclear Material (SNM), which the
licensee was required to account for. The incore detectors were located at regularly
spaced intervals near one end of the incore detector string. When the incore detectors
no longer functioned correctly, the entire incore detector string would be removed from
the reactor and stored underwater in the spent fuel pool, due to the high radiation dose
rates emanating from the irradiated incores. The incore detector strings would
periodically be disposed of as waste to provide additional space in the spent fuel pool.
To dispose of the incores, the personnel would remove sections from the incore that
contained the incore detectors and store these sections separately. The remaining
pieces of the incores, that did not contain the incore detectors, would be cut up into
lengths that could be easily handled and were either stored in the spent fuel pool or
shipped offsite.
The licensee had located an extensive collection of records that documented the history
of the incores at HBPP. The Special Nuclear Material Accountability Record had been
located for each incore that had been used at HBPP. The SNM Accountability Records
documented the movements of each incore from the warehouse to disposal, along with
associated dates. The inspectors reviewed the SNM Accountability Records along with
records of radioactive material shipments, procedures used to cutup the incores and
other miscellaneous correspondence that related to the missing incore detectors.
The first planned shipment of incore detectors and incores for disposal occurred on
December 12, 1968. The HBPP On-site Review Committee Minutes of Regular
Meeting, dated December 3, 1968, discussed a proposal to remove the incore detectors
from the six defective incores that were located in the spent fuel pool and cutup the
remaining sections into approximately four foot lengths to fit into an available cask for
shipment offsite. The Radioactive Materials Shipment Record, dated December 12,
1968 and the SNM Material Accountability Records for incore detector serial numbers
5451136, 5451137, 5451138, 5451140, 5451141, 5451142 confirmed that both the
incore detectors and the cutup incores had been shipped offsite to Nuclear Engineering
Co., Beatty, Nevada, for disposal.
The second planned shipment consisted of nine incore detectors removed from three
selected incores that were located in the spent fuel pool. Documentation indicated that
the left over incore pieces had been stored in the spent fuel pool. A letter from General
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Electric Co., San Jose, California, dated May 7, 1973, documented plans for GE
personnel to remove the incore detectors from incore serial numbers 5451154, 5808867
and 5808868. The incore detectors or elements were then planned to be returned to
General Electric Co., Vallecitos, California, for examination. HBPP Radioactive
Materials Shipment Record No. 215, dated June 25, 1973, confirmed the shipment of
the nine incore fission chambers from strings, Serial Nos. 5451154, 5808867, &
5808868," which indicated that only the incore detectors had been shipped. A typed
record of the events that occurred on June 21, 1973, documented that the incore
detectors had been cutup into two foot sections and stored in a separate compartment
of GEs cask liner for shipment, while the other short pieces were to be placed in one
of the storage cans prepared for plant use. This record also supported that only the
nine incore detectors had been shipped leaving approximately 400 inches of incores in
one of the storage cans presumably in the spent fuel pool.
At the time of the segmenting of the incore detectors for General Electric in 1973 there
were nine additional incores in the spent fuel pool. Although detailed records or copies
of the procedure used to cutup these nine incore detectors strings were never located, it
appeared that this operation occurred at approximately the same time as the
segmenting of the incore detectors for GE. A handwritten note from the April 1973 time
frame indicated that we might as well cut them all up while we are at it. The incores
were most likely cutup between June 22 and 25, 1973. A HBPP Memorandum to File,
dated February 24, 1986, documented that the remnants of nine incores cutup in earlier
years were located in the spent fuel pool.
In December 1985, HBPP Temporary Procedure 11/25/85 No. 2, Revision 146-12/85
was used to cut the incore detectors from nine intact incores located in the spent fuel
pool. The procedure provided specific directions and diagrams for removing the incore
detectors. Additionally, the presence of the incore detectors were determined by
changes in dose rate readings as detailed in Supplement to T.P.11/25/85 No. 2. The
HBPP Memorandum to File, dated February 24, 1986, documented that nine incores
were cut and 27 incore detectors were removed. By procedure, the cutup sections that
contained the incore detectors would be either 10 or 11 inches long. The remaining
pieces of incores cutup by use of the procedure were reported to have been included in
shipment number 473, to Barnwell, South Carolina that occurred on December 15,
1985. This shipment listed three barrels that contained a total length of 1520 inches of
processed incores, corresponding to the expected amount of waste from the nine
cutup incore pieces, minus the 27 incore detector segments.
Soon after the cutup and shipment of the nine incore waste pieces that occurred in
December 1985, HBPP personnel attempted to account for all the incore detectors.
They found cutup incore remnants that consisted of 49 pieces approximately 25 to
30 inches in length and 5 pieces approximately 18 inches in length. The total length of
the incores evaluated by HBPP personnel (including the 27 incore detectors from the
nine detector strings cutup in 1973) was estimated between 1315 to 1560 inches. This
total did not include the incore detectors recently cutup in December 1985 of
approximately 400 inches. A dose rate survey of the incore pieces was conducted to
locate the missing incore detectors. The results of the dose rate surveys were
inconclusive. The Memorandum noted that due to variations in activation of the fission
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chambers and decay times, positive identification of the fission chambers was not
possible. However, based on the total length of the incores and the dose rate
measurements, the licensee concluded that all fission chambers were accounted for.
As part of the effort to positively account for all SNM at HBPP, the licensee performed
an inventory of all the incore detectors onsite. HBPP procedure TP 2004-10, Incore
Detector Evaluation and Container Loading, Revision 5 provided instructions to
determine if the incore segments contained an incore detector. The procedure required
measurement of the individual incore piece lengths and positive verification of the
presence of an incore detector. The results of this inventory was reported to the NRC
on February 22, 2005, which concluded that one full and three partial incore detectors
were not in the spent fuel pool as previously believed. The three partial incore
detectors, located by the licensee, were found in incore segments approximately
30 inches in length. The licensee reported that the total length of the incores (including
incore detectors) that remained in the spent fuel pool was 2,046 inches. This reported
length of incore detectors and incore pieces closely matched the total length of incores
documented in the HBPP Memorandum to File, dated February 24, 1986. The single
exception was an equivalent length of approximately 400 inches of cutup incore pieces
from the 1973 time period.
The precise location of the missing segments from the full and partial length incore
detectors can not be determined. Approximately 400 inches of incore segments,
including the missing incore detectors, cannot be located or accurately accounted for.
The missing incore detectors were most likely included in a LLRW shipment along with
portions of other incore segments from the 1973 cutup campaign. Evidence exists that
the 1973 cutup campaign produced segments of 25 to 30 inches in length. The
inspectors concluded that the documented shipments of incores would not have
included the missing full or partial incore detector segments for the following reasons:
- The shipment in 1968 included all the components (both strings and incore
detectors) from the six incores that existed in the spent fuel pool. No incore
detector pieces were reported to have been left in the spent fuel pool.
- According to available records the shipment to GE in 1973, only included the
incore detectors. Evidence suggested that approximately 400 inches of cutup
incores were stored from the campaign at HBPP. No shipment records or other
documentation to account for the 400 inches of cutup incores from this shipment
were located.
- The three partial incore detectors were located by the licensee in incore
segments that were approximately 30 inches in length.
- Records related to the shipment made in 1985 indicated that only the recently
cutup incore segments from the campaign conducted several weeks prior to the
shipment were included. Documentation indicated that the incore detector
segments stored in the HBPP spent fuel pool from the 1985 cutting operation
-32-
contained incore detectors between 10 and 11 inches long. Therefore, the
probability that a 30-inch segment remained at HBPP from the cutting
operation/shipment conducted in 1985 is very small.
- HBPP personnel noted that 49 incore pieces that were 25 to 30 inches in length
were in the spent fuel pool in 1986, presumably from the 1973 cutup campaign.
- The licensee performed a comprehensive search that determined the number of
incore detectors that are currently in the spent fuel pool. Based on the HBPP
Memorandum to File, dated February 24, 1986, the amount of material that
existed in the spent fuel pool in 1886 closely matched the amount recently
reported by the licensee.
The licensee records were inconclusive as to the possible location for approximately
400 inches of incore detector strings, presumably cutup in 1973. Based on a review of
the available information, the inspectors agreed with the licensee conclusion that the
missing incore detectors were most likely located at a licensed LLRW disposal facility.
Since the incore detectors would have been highly radioactive and therefore stored in
the spent fuel pool, the most likely LLRW disposal sites were determined to be either
Barnwell or Hanford. The suspect LLRW shipments mirror those considered for the
missing fuel rod segments that would have occurred between 1983 and 1986.
6.3 Conclusions
The licensee had located an extensive collection of records that documented the history
of the incore detectors at HBPP. A number of shipments of cutup incore segments and
intact incore detectors were documented.
Records were inconclusive as to the whereabouts of approximately 400 inches of cutup
incores, presumably from the campaign performed during June of 1973. Documentation
indicated that the partial incore detectors found by the licensee had been cutup during
this campaign.
The inspectors agreed with the licensees conclusions that the most likely locations for
the missing full and three partial incore detectors were either the Barnwell or Hanford
LLRW disposal facility.
7. Review of Scenario Involving Fuel Segments Stolen or Diverted
7.1 Inspection Scope
The inspectors reviewed the licensee interim and final reports sections related to the
theft and diversion scenario, interviewed personnel involved in the development of this
portions of the licensee reports, examined supporting documentation and reviewed
special evaluations and calculations.
7.2 Observations and Findings
-33-
The licensee identified three alternatives for this scenario:
7. Theft by an External Entity
8. Theft by an Insider
9. Unauthorized Disposal
The licensee analysis involved a defense-in-depth approach meaning that for a
successful theft or diversion to have occurred, multiple barriers in place to prevent such
an occurrence would have to have failed. In addition to the analysis performed by the
licensee, the inspectors requested that the licensee conduct some additional evaluations
not detailed in the licensees report. The inspectors requested that the licensee perform
a calculation to demonstrate that the plant radiological monitoring system could have
detected and would have generated an alarm if one unshielded 18-inch segment would
had been removed from the SFP. The inspectors also requested the licensee evaluate
available records of unexpected alarms and determined if plant personnel had
responded. The licensee evaluations demonstrated that a single unshielded 18-inch
segment would have generated an alarm and that for unexpected alarms the licensee
personnel responded to evaluate the cause. The licensee evaluations and the
inspectors independent review support the conclusions listed in Section 4.5.6 of the
licensees Final Report. These conclusions include:
- Few individuals knew of the existence of the three 18-inch fuel segments
- Theft of unshielded fuel segments in the 1968 through 1974 period would have
presented significant health risks due to radiation exposure.
- Theft of fuel segments using a shielded container would have required
knowledge of a large number of plant employees and the use and manipulation
of major plant equipment that would not have gone on unobserved. No evidence
of such use has been found.
- There is very limited economic or strategic value to the fuel rod segments or the
incore detectors.
- No group or individuals have claimed to have stolen or diverted the fuel rod
segments or incore detectors.
7.3 Conclusions
The inspectors agreed with the licensees conclusion that theft or diversion of the three
18-inch fuel rod segments and incore detectors was highly unlikely.
8. Review of Scenario Involving Fuel Segments Remaining in the SFP in an Altered
Condition
8.1 Inspection Scope
The inspectors reviewed the ATI Consulting report Evaluation of Nuclear Fuel Rod
Fragments and Inference to Fuel Rod A-49 at Humboldt Bay Power Plant (ATI report)
dated March 31, 2005, and other related documents and procedures, and reviewed
video and still images of the fuel fragments found.
-34-
8.2 Observations and Findings
In a meeting held on September 17, 1968, by the HBPP On-site Review Committee
(OSRC) led by W. A. Raymond (Acting Chairman), the committee decided that a fuel
segment will be removed from a corner rod of bundle A-49. This fuel segment would
then be cut in three 18 inch segments from this irradiated fuel rod and shipped to
Battelle Memorial Institute in Columbus (BMI). The top and end pieces of the fuel rod
were to remain in the SFP. The three rod segments were to be used in a study
regarding Type 1 fuel rods and were to be shipped in a specially made shipping
container. The study by BMI was canceled prior to shipment and the three 18-inch fuel
rod segments and pipe container were placed back in the SFP.
During the fall of 2003, Pacific Gas and Electric (the licensee) conducted an
examination of the contents of its SFP in preparation for removal of the fuel for
placement into dry storage in an onsite Independent Spent Fuel Storage Installation.
Subsequently, on June 23, 2004, the licensee discovered a discrepancy in the plant
records related to the three 18-inch rod segments such that there was no accounting for
the removed fuel rod or segments from Assembly A-49. The licensee contracted with
ATI Consulting to review digital video and photographs of the inventoried fuel rod
fragments to determine if they may be part of the remnants and cut segments from the
fuel rod fragments of Assembly A-49.
The inspectors reviewed each section of the ATI report and repeated the visual
assessment of each fuel fragment that the consultants performed in the ATI report. The
inspectors also reviewed each document used by the consultants listed in the Sources
of Data Evaluated Section of the ATI report. Each of the documents are listed in the
attachment to this inspection report. The ATI report was divided into seven sections that
included: 1) Executive Summary; 2) Background; 3) the Sources of Data Evaluated; 4)
General Assessment; 5) Evaluation Criteria; 6) Data and Discussion; and
7) Conclusions.
In the General Assessment Section of the ATI report, the consultants discussed the
history of the GE Type 1 fuel with Type 304 stainless steel cladding regarding failures
due to intergranular stress corrosion cracking (IGSCC). The report also described the
dimensions of a typical Type 1 fuel rod that is representative of the stainless steel clad
fuel rods in Assembly A-49 and the cutting plan for the subject fuel rod.
The inspectors reviewed a paper by R. N. Duncan, et al, in titled Stainless-Steel-Clad
Fuel Rod Failures, and General Electric Company (GE), Nuclear Applications Vol.1
(pp 413-418), dated October 1965 which discussed the failure of the Type-304 stainless
steel fuel rods by IGSCC. The inspectors reviewed this paper in order to determine if the
ATI consultants were accurate in explaining the cause of the fragmentation of the
subject fuel rod. The inspectors were also aware of substantial efforts in research and
development that had been sponsored by the BWR (Boiling Water Reactor) Owners
Group for IGSCC Research. The results of this program, along with other related work
by vendors, consulting firms, and confirmatory research sponsored by the NRC allowed
the NRC staff to development positions regarding the IGSCC problems in BWRs. The
technical bases for these positions were detailed in NUREG-0313, Revision. 2
-35-
"Technical Report on Material Selection and Process Guidelines for BWR Coolant
Pressure Boundary Piping." Based on these studies, the inspectors determined that the
ATI consultants were correct in their assessment that the subject rods fragmentation
was caused by IGSCC.
The ATI consultants noted that the axial dimension, not including the endplug shanks at
the top and bottom ends of the rod, was approximately 83 inches. The consultants
further noted that the top endplug shank was slightly longer than one inch, while the
bottom endplug shank was slightly longer than 0.5 inches. Additionally, each fuel rod
had an identification stamp at the bottom end of the rod above the endplug shank. The
inspectors reviewed General Electric Drawing Number 932C653, Titled ASM Fuel Rod
and verified that the consultants were accurate in their description of the subject fuel rod
in the ATI report.
The inspectors also reviewed the licensees cutting plan and the ATI consultants
evaluation of the licensees cutting plan of the subject fuel rod. The cutting plan was
contained in the OSRC meeting notes dated September 17, 1968, along with a sketch
showing the A-49 corner rod and a second cutting plan that would require five cuts to
produce the three 18-inch segments. The consultants in their report termed this
drawing as the alternate cutting plan. The inspectors found that the ATI consultants
were methodical and sound in their engineering judgement in determining the process
the licensee used in the cutting plan of the subject fuel rod.
In the Evaluation Criteria Section of the ATI report, the consultants developed a basis
for the assessment of the fuel rod segments that consisted of five criteria: (1) planarity/
perpendicularity of the end surfaces of the individual fuel rod fragments, relative to their
axial orientation; (2) appearance of the separated surfaces of the cladding, when viewed
normal to the separated surface; (3) flushness of the separated surfaces of the fuel
pellets with the separated surfaces of the cladding; (4) appearance of the separated
surfaces of the fuel pellets, when viewed normal to the separated surface; and
(5) degree of associated intergranular stress corrosion cracking adjacent to the
separated surface. The ATI consultants also developed criteria to identify the deference
between ends of broken segments produced by cutting, verses ends of broken
segments produced by other failure mechanisms, e.g, IGSCC or tearing. The
inspectors found that when they repeated the visual assessment of each fuel rod
fragment utilizing the five criteria developed by the ATI consultants, the criteria were of
sound engineering judgement and provided a useful tool in determinating the end
conditions of the subject fragments.
In the Data and Discussion Section of the ATI report, the consultants listed the fuel
fragments and findings of their assessment for each fuel rod fragment. The inspectors
repeated the visual assessment of each fuel fragment that the ATI consultants
performed. These fragments are listed in Table 2 of this report along with the
inspectors findings.
-36-
Prior to their visual assessment of the subject fragments, the inspectors reviewed the
licencees procedure TP 2400-08 Fuel Fragment Evaluation and Container Loading,
dated May 12, 2005. Procedure TP 2400-08 was used by the licensee to evaluate the
fuel fragments and to determine their physical characteristics. It also provided
instructions for loading fuel fragments into compartmental container trays or unclad fuel
fragment container boxes. In TP 2400-08 the licensee characterized the different types
of fuel fragments e.g., Type I (304 stainless steel clad), Type II (zircaloy clad), and Type
III and Type IV (both are zircaloy clad and are of a larger diameter). According to the
procedure, three tests were performed by the licensee on each of the fragments to
determine their characteristics. For example, 1.) a go/no-go test was performed to
determine if the fragment was of a smaller diameter Type 1 or Type II fuel rod verses
the larger diameter Type III and IV fuel rods; 2.) a magnetic test was performed to
distinguish the Type I and the other types of fuel rods (a stainless steel clad fuel rod is
slightly magnetic whereas the zircaloy clad fuel is non-magnetic); and 3) an ultrasonic
examination was performed on the fragments to determined the wall thickness of each
fragments to distinguish the different fuel types since there is a difference in thickness
for various fuel types. The licensee also measured the does rate of each fragment and
the length of the fuel segment. The inspectors determined that the licensees procedure
TP 2400-08 was a sound engineering approach to distinguish the different types of fuel
rods.
The licensee recorded and documented its data by video camera and on a fuel fragment
evaluation data sheet. The video camera was a Remote Ocean Systems (ROS) CE-X
Miniature Environmental Color Zoom Camera Serial Number 1090. The NRC had
authorized alternatives to the American Society of Mechanical Engineers Boiler and
Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of
Nuclear Power Plant Components allowing licensees to perform an enhanced VT-1
visual examination with a high resolution camera that can be calibrated to focus on a
.001 inch wire in lieu of ASME Code surface nondestructive examinations e.g., dye-
penetrans or magnetic particle examination.
The inspectors were able to visually identify the measurement line increments of the
ruler used by the licensee to measure the fuel fragments. The inspectors judged the
line increments of the ruler to be 1/64 inch or .016 inches wide. The inspectors
compared the specifications of the licensees camera to one that was evaluated in
NRCs NUREG/CR-6860, An Assessment of Visual Testing and found that the
licenseess camera was comparable to one listed in the NUREG. The inspectors were
aware that the licensee did not calibrate its camera to focus on a .001 inch wire;
however, the inspectors did determine that the licensees camera imaging did have the
capability to distinguish between a mechanical cut and fracture of a fuel fragment by
IGSCC or other means.
The inspectors repeated the visual examinations described in the ATI report. Using the
ATI consultants five criteria basis for the assessment of the fuel rod fragments, the
inspectors found that all the fragments as shown in Table 2 match the ATI report
description. The inspectors also inspected two additional fragments FF-001 and
FF-020. Fragment FF-001 was a top end fuel assembly segment with one end that
appeared to have been fractured by IGSCC. Fragment FF-020 was identified as a
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bottom end fuel assembly fragment with a serial number of PH-5177. Both FF-001 and
FF-020 fragments were not considered part of fuel assembly A-49 in the ATI report.
Table 2
Humboldt Bay Power Plant Unit 3 - Fuel Rod Fragments Examined From ATI Report
Fuel Rod Length Match ATI End Fragment? End Condition Rad Dose on Rad Dose 6 Remarks
Fragment (Inches) Report of Fragments Contact (R/hr) Inches From
No. Description Fragment
Surface (R/hr)
FF009 30.25 Yes Top End fuel One end is 183 15 None
rod fragment jagged and no
sign of cutting
FF013 4 Yes No Fractures on 230 9 Partial cut mark on surface
both ends of of fuel rod fragment and
fuel rod could be considered as
fragment part of
A-49
FF021 14 Yes Bottom End of One end split 198 10 ID Pin Number PH-5155
fuel rod and folded
fragment back across
fuel rod
FF026 11 Yes Top End of fuel One end is cut 209 7.5 Fuel rod fragment meets 5
rod fragment point ATI Report Criteria
FF027 6.25 Yes No One end of fuel 303 15 None
fragment
appears cut
and the other
end is bent
FF028 1 Yes No Fractures on 136 1.5 None
both ends of
the fuel rod
fragment
FF029 1 Yes No Fractures on 101 1.3 None
both ends of
the fuel rod
fragment
FF030 4.5 Yes No Fractures on 325 7.0 None
both ends of
the fuel rod
fragment
FF031 2.75 Yes No Fractures on 216 4.5 None
both ends of
the fuel rod
fragment
FF032 4.5 Yes No Fractures on 328 5 None
both ends of
the fuel rod
fragment
FF033 3.625 Yes No One end 275 5 None
appears cut
and other end
is fractured
FF034 3.25 Yes No Fractures on 271 12 None
both ends of
the fuel rod
fragment
FF020 16.5 N/A Bottom End of Fractured on 225 12 This fragment was not
fuel rod end of fuel rod considered as part of A-49
fragment fragment in the ATI Report. ID as
PH 5177
FF001 52 N/A Top End of fuel Fractured on 250 116 This fragment was not
rod fragment end of fuel rod considered as part of A-49
fragment in the ATI Report.
-38-
Fragment FF-021 was a bottom end fragment and had the serial number PH-5155
stamped on it. The ATI consultants considered this fragment as part of the A-49 fuel
rod. Neither the licensee nor GE could produce records to confirm whether fuel rod
Serial Number PH-5155 was part of fuel assembly A-49. The inspectors determined
that for positive identification, the serial number for FF-021 needed to be confirmed. The
opposite end of the pin end was spilt and folded back toward the pin end.
The ATI consultants also identified fragments FF-026, and FF-013 as potential portions
of A-49. The inspectors found that fragment FF-026 was a top end and the opposite
end appeared to have been cut by mechanical means. However, the inspectors did not
agree with the ATI consultants that FF-026 may have been part of A-49, without
additional examination either by chemical analysis or microscopic examination.
However, the inspectors realized that it was not practical to perform these tests due to
the high radiation doses that would be encountered. Furthermore, the individual fuel rod
manufacturer specifications were not available and without these specifications the
results of these tests would not produce meaningful data. The inspectors also found
that for fragment FF-013, it was approximately 4 inches long and both ends were
fragmented by what appeared to be IGSCC. The inspectors identified an aborted partial
mechanical cut on fragment FF-013 as did the ATI consultants. The inspectors
determined that fragment FF-013 could be a fragment of A-49. The inspectors findings
regarding all other fuel fragments were similar to the findings of the of the ATI
consultants with the exception that the inspectors did not agree that FF-021 was part of
A-49 without further testing.
The inspectors also identified that some of the fragments appeared to be bent as if a
dynamic load had been placed on the rods. In discussions with the licensee, review of
spent fuel pool handling procedures, and observation of the spent fuel pool, the
inspectors determined that it was unlikely that dynamic loading caused the bending of
the fragments. The inspectors determined that more than likely IGSCC weakened the
fuel rod fragments and the weight of the fuel rod itself and the repositioning of the fuel
assemblies in the spent fuel pool caused the bending of the fuel rod fragments.
The inspectors evaluated the possibility that the missing pipe container in which the
licensee had placed the three A-49 18-inch long fuel segments could have dissolved in
the SFP. The container was a carbon or stainless steel 11/2 Schedule 40 pipe capped at
both ends, with a welded hook on one end of the container. The outside diameter was
1.90 inches and wall thickness 0.145 inches. The licensee believed that the container
was shipped with other contaminated waste material or it was on the bottom on the fuel
pool in fragments. There had been discussion by the licensee that the pipe container
had dissolved in the SFP. The inspectors reviewed SFP water quality data sheets and
found that the chemistry of the SFP water was fairly constant and had only experienced
a high acid content for a couple of short periods. The inspectors also reviewed the
monthly spent fuel pool water quality check procedure and found it an acceptable
procedure to insure he SFP water quality. The inspectors determined that if the
container had corroded into fragments there should be remnants left in the SFP. The
licensee did a search for the pipe container and did not find any remains in the SFP.
Therefore, the inspectors determined that the container was not in the SFP and that it
more than likely was shipped offsite as contaminated waste.
-39-
8.3 Conclusions
The inspectors concluded that the ATI report was based on sound engineering judgment
and the ATI consultants were methodical in the process of determining the conditions of
the fuel rod fragments. However, the inspectors concluded that without substantial
additional test, they could not agree the ATI consultants conclusion that there was
reasonable evidence that the 18-inch segments maybe among the fragments found in
the SFP.
The inspectors concluded that the cause of the bent fragments was most likely
Intergranular Stress Corrosion Cracking (IGSCC), that weakened the fuel rods with the
weight of the fuel rod itself causing the bending. In addition, the inspectors concluded
that the repositioning of the fuel assemblies in the spent fuel pool also may have
contributed to the bending of the fuel rods.
The pipe container for the missing segments was unlikely to have dissolved in the SFP.
If the pipe container corroded into fragments there would have been remnants of it in
the SFP. The inspectors further concluded that the container was more than likely
shipped to a LLRW site as irradiated material.
9. Cause Analysis
9.1 Inspection Scope
The inspectors reviewed licensee reports, records, procedures, and interviewed
personnel to determine whether the cause analysis performed was thorough and well
documented.
9.2 Observations and Findings
The inspectors reviewed HBPP Procedure Number HBAP C-12 #2, Revision 7, 2/14/05,
Technical Review Group and Nonconformances, and Application of HBAP C-12 #2
Cause Analysis Guidelines to SNM Control and Accountability Issues at HBPP, dated
4/14/05, by Roger Johnson, and interviewed key licensee personnel.
The cause analysis was conducted by Project personnel who were contractors and
independent from the organizations responsible for the activities evaluated. The cause
analysis utilized a barrier analysis and an simplified event-cause tree analysis. These
are two tools often used in root cause analysis. The licensee was not committed and
was not required to perform a root-cause analysis. Although the process used by the
licensee was not a root-cause analysis, but a less stringent cause analysis, the
inspectors concluded that the licensee considered all reasonable causes. No alternative
causes were identified by the inspectors.
As previously noted in Section 2.f, although the SNM Control and Accountability Project
documentation did not always include the basis for the conclusions, no instances of
erroneous or unreasonable conclusions were identified.
-40-
The licensees process identified causes, characterized barriers, and recommended
immediate corrective actions (ICA) and corrective actions to prevent recurrence (CAPR).
Further, the licensee determined potential causes associated with the loss of control of
fuel fragments, the missing fuel rod segments and the missing incore detectors. The
causes, barrier analysis and ICA and CAPR are summarized in Section 6 the licensees
Final Report.
Once the licensee recognized that it was likely that SNM was missing, they promptly
notified the NRC and initiated a search for the missing SNM and any other SNM
fragments. The corrective actions included revising procedures, cataloging and
characterization the fuel fragments and SNM waste found to ensure a complete and
accurate accounting and tracking of all SNM in PG&Es possession at HBPP, down to
the fragment level. The corrective actions also included developing a program to ensure
that SNM Custodians are appropriately trained and qualified. The inspectors concluded
that the corrective actions taken and proposed by the licensee where through, complete
and comprehensive.
The licensee missed several opportunities to correct their MC&A program to address the
three missing approximately 18-inch long fuel fragments and other SNM in its
possession. Four of the more significant opportunities were:
6. On August 3, 1966, an internal memorandum directed plant staff to keep track of
fuel rod pieces and to make entries on the control operators log regarding fuel
rod pieces that were found. The memorandum included the following statement:
In those cases where portions of fuel rods are broken off of the bundle, the
inspector should estimate as accurately as possible, the total number of rods (or
portions of rods) which are missing. We are required to account for all of the
uranium that we possess, and so we will have to estimate as accurately as
possible the amount of fuel which ends up in the pellet catcher. (Bold font
added for emphasis). Although the licensee recognized the need to maintain
control of SNM and to account for it accurately, no specific actions to maintain
accounting and control appear to have been taken.
7. On October 22, 1974, ANSI Standard N15.8-1974 was approved and on June
1975 this standard was endorsed by NRC Regulatory Guide 5.29. In Section
6.1, Internal Control, the ANSI Standard described the unit of control as
follows: "The basic unit of control for nuclear material shall be the nuclear fuel
assembly. Each nuclear fuel assembly shall be identified in the material control
records by its serial number and location. Nuclear material contained in fuel
elements, not part of an assembly, shall be separately identified on all
material control records." (Bold font added for emphasis). In this statement,
the standard and the endorsing regulatory guidance identified to all licensees the
need to account for and control nuclear fuel that had become separated from its
assembly, but no action appears to have been taken by the licensee.
8. The licensees November 14, 2003, response to NRC Bulletin 2003-004, which
requested that licensees perform a one-time reporting of SNM quantities of 1
gram or more of contained uranium-235, was based on the September 2003
-41-
inventory that did not include the fuel fragments present in the spent fuel pool.
Opportunities to acknowledge and include fuel fragments in the SNM reported
quantities included a recent discovery of a fuel fragment on November 12, 2003,
only days before the licensee submitted their response to NRC Bulletin 2003-
004. No action was taken by the licensee to adjust their accounting records to
account for the found fragment or other fragments that existed in the spent fuel
pool.
9. During the physical inventories performed annually from 1971 through 2003
(except for those years when the pool was covered and the licensee was given
an exemption from the requirement to perform inventory), the presence of fuel
fragments should have been identified and the SNM inventory records updated
to account for them. The licensee missed multiple opportunities to identify that
the segments were missing and to account for the rod pieces in the spent fuel
pool. Comparison of the book inventory with the results of the physical inventory
would have shown that the book inventory was incorrect, but the licensee did not
appear to have made this comparison.
The licensee missed all of the opportunities described above and did not initiate a
reevaluation of the SNM inventory until January 2004. This reevaluation was
undertaken partially in response to concerns expressed by the inspectors about the
accuracy of the existing book inventory in light of the six fuel fragments that were found
in containers in the SFP during November and December 2003, and uncertainty about
the inventory of zirconium clad assemblies from which rods had been removed.
9.3 Conclusions
The cause analysis performed by the licensee followed the applicable procedure and
appeared to be through and adequate. Although the process used by the licensee was
not a root-cause analysis, but a less stringent cause analysis, the inspectors concluded
that the licensee considered all reasonable causes. The identified corrective actions
were complete and comprehensive. The inspectors identified several missed
opportunities to correct the MC&A program to address the three missing approximately
18-inch long fuel fragments and other SNM in its possession.
10. Health and Safety Consequences
10.1 Inspection Scope
The inspectors reviewed the licensees evaluation of consequences to public health and
safety as well as to the environment due the loss of the 18-inch fuel segments and
incore detectors. The inspectors also evaluated the safety analysis performed for the
Millstone missing fuel rods for its applicability to the missing SNM from HBPP.
10.2 Observations and Findings
Section 5.2 of the licensees Final Report titled Health and Safety, described the
evaluation the licensee performed for the potential consequences to the public health
-42-
and safety or to the environment due the loss of the 18-inch long fuel segments.
Section 3.3.1 of the Final Report addressed potential consequences to the public health
and safety or to the environment due to the loss of the incore detectors.
The licensee evaluated three possible locations for the 18-inch long fuel rod segments:
- They were still in the SFP
- They were shipped to NFS for reprocessing, or
- They were shipped to Barnwell or Hanford LLRW sites
The licensee concluded that if the fuel rod segments are in the SFP, they are in a safe
location and there is no increased risk to the health and safety of the public, workers, or
the environment. If the fuel rod segments were shipped to NFS, the shipping and
processing was in accordance with approved methods and there was no increased risk
to the health and safety of the public, workers, or the environment.
The licensee also concluded that if the fuel rod segments were shipped to either
Barnwell or Hanford, the shipment process did not pose a significantly increased risk to
the health and safety of the public, the workers, or the environment. Also the potential
burial of the fuel rod segments at either of these LLRW facilities would not increase the
risk to the health and safety of the public, site workers, or the environment. Both of the
LLRW facilities were designed and licensed to safely dispose of all radionuclides
contained in the three fuel rod segments, and all of the radionuclides contained in the
three fuel rod segments were already present in the inventories of those facilities at
amounts that far exceeded the contents of fuel rod segments. The fuel rod segments
would add only a very small amount to the radionuclide inventories at these LLRW
disposal facilities.
On April 14, 2004, NRC released the safety analysis reports of the long-term hazard of
Millstone Unit 1s missing spent fuel rods potentially disposed of at the Barnwell and
Hanford commercial LLRW disposal facilities. These reports noted that the inventory in
the Millstone Unit 1s two missing spent fuel rods was a very small fraction of the
radionuclide inventories already present at these two LLRW disposal facilities.
Millstones two missing rods contained SNM in a quantity of 132 grams of uranium-235,
27 grams of plutonium, and a total of 518 curies of activity. The HBPP three 18-inch
missing rods segments contained SNM in an approximate quantity of 17 grams of
Uranium-235, 5 grams of plutonium, and a total of 80 curies of activity. The radionuclide
contents of the three 18-inch missing rods segments were only a fraction of the
inventory in the Millstone Unit 1s two missing spent fuel rods.
The NRC safety analyses concluded that although the LLRW sites are not licensed for
disposal of nuclear fuel, the overall risk due to the potential presence of the Millstone
fuel rods at either Barnwell or Hanford, was minimal to both the present workers and
future generations of the public. The risks associated with locating and retrieving them
would likely result in more actual dose being delivered to the workers than the potential
dose future generations could receive if the rods were not retrieved. Based on the
extremely low risk that the fuel rods posed, if they were at Barnwell or Hanford, retrieval
of the rods would not be justified by arguments concerning public health and safety.
-43-
Considering that the radionuclide inventory for the HBPP missing fuel segments was a
fraction of the inventory of Millstones two missing spent fuel rods, the inspectors
concluded that if 18-inch fuel rod segments were at either site, the risk is minimal to
both the present workers and future generations of the public. Additional efforts to
locate and retrieve the missing 18-inch fuel rod segments would not be warranted. The
overall risk from 18-inch fuel rods segments, if present, would be minimal to the health
and safety of the public, workers, or the environment.
Since the SNM inventory from the missing incore detectors was considerably less than
the 18-inch fuel rod segments (estimated at 0.035 grams of uranium-235), it is evident
that the overall risk from the missing incore detectors, if presence at either Barnwell or
Hanford, would also be minimal to the health and safety of the public, workers, or the
environment.
10.3 Conclusions
The inspectors concluded that regardless of whether the missing fuel segments were
located in the SFP, had been shipped to NFS for reprocessing, or had been transferred
to a LLRW disposal facility, the overall risk from the 18-inch fuel rods segments was
minimal to the health and safety of the public, workers, or the environment. Based on
the extremely low risk that the 18-inch fuel rods segments posed, if they were at
Barnwell or Hanford, attempts to locate and retrieve the 18-inch fuel rods segments
would not be justified by arguments concerning public health and safety. The overall
risk from the missing incore detectors, if present at either Barnwell or Hanford, would
also be minimal.
11. Discussion of Apparent Violations and Previously Identified Unresolved Items
11.1 Apparent Violations
In NRC Interim Inspection Report 05000133/2005001, the inspectors identified and
documented four apparent violations and three unresolved items. As noted in the
report, the licensee identified the missing 18-inch irradiated fuel segments and the
missing one complete and three partial incore detectors; promptly notified the NRC
when it determined that the material was missing and promptly initiated a search,
evaluation of the problems and corrective actions. As a result of the Special Inspection
chartered to review all information related to the missing SNM, the inspectors identified
the following apparent violations:
A. 10 CFR 74.19(a)(1), formerly 10 CFR 70.51(a)(1), requires, in part, that the
licensee shall keep records showing the receipt, inventory (including location and
unique identity), acquisition, transfer, and disposal of all SNM in its possession
regardless of its origin or method of acquisition.
1. Contrary to the above from August 6, 1969 (date when assembly A-49
was shipped off site) to July 16, 2004 (date when PG&E determined that
the segments were missing), PG&E, failed to keep records showing the
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inventory, transfer or disposal of three approximately 18-inch segments of
irradiated fuel containing approximately 22.5 grams of SNM.
2. Contrary to the above from June 25, 1973 to February 4, 2005, the
licensee failed to keep records including location and unique identity
showing the inventory, transfer or disposal of one complete and three
partial incore detectors containing a total of approximately 0.035 grams of
SNM.
These failures are an apparent violation of 10 CFR 74.19(a)(1)
(APV 50-133/0501-03).
B. 10 CFR 74.19(b), formerly 10 CFR 70.51(b), requires that each licensee that is
authorized to possess SNM in a quantity exceeding one effective kilogram at any
one time shall establish, maintain, and follow written material control and
accounting procedures that are sufficient to enable the licensee to account for
the SNM in its possession under license. The licensee shall retain these
procedures until the Commission terminates the license that authorizes
possession of the material and retain any superceded portion of the procedures
for 3 years after the portion is superceded.
Contrary to the above, from June 4, 1971 (date when last Type 1 fuel assembly
was shipped off site) to July 16, 2004 (date when PG&E determined that the
segments were missing), PG&E, a licensee authorized by NRC License DPR-7
to possess SNM in a quantity exceeding one effective kilogram, failed to
establish, maintain, and follow written material control and accounting
procedures sufficient to enable PG&E to account for the SNM in its possession
under license DPR-7. Specifically, PG&E failed to account for SNM located in
the HBPP SFP consisting of a quantity of 111 grams of uranium-235, 27 grams
of plutonium contained in the remnants from Type 1 damaged fuel assemblies
(fuel fragments and SNM waste), and incore detectors.
This failure is an apparent violation of 10 CFR 74.19(b) (APV 50-133/0501-04).
C. 10 CFR 74.19(c), formerly 10 CFR 70.51(c), requires each licensee who is
authorized to possess SNM, at any one time and site location, in a quantity
greater than 350 grams of contained uranium-235, uranium-233, or plutonium, or
any combination thereof, shall conduct a physical inventory of all SNM in its
possession under license at intervals not to exceed 12 months.
Contrary to the above, PG&E, a licensee authorized to possess SNM at the
HBPP in quantities greater than 350 grams of contained uranium-235, uranium-
233, or plutonium failed to conduct a physical inventory of all SNM in its
possession at intervals not to exceed 12 months. Specifically, inventories
performed by PG&E from June 4, 1971 (date when last Type 1 fuel assembly
-45-
was shipped off site), to February 4, 2005, with the exception of periods when
the sealed SFP cover was in place, did not include fuel fragments and other
SNM remnants from Type 1 damaged fuel assemblies and all incore detectors.
This failure is an apparent violation of 10 CFR 74.19(c) (APV 50-133/0501-05).
Based on information provided by the licensee and upon further evaluation, the
inspectors concluded that the previously identified apparent violation related to the form
that the licensee was authorized to possess SNM is controlled by the conditions of the
license and not technical specification 4.2. License Condition B.2(d) states that the
licensee is authorized to possessed 1000 kilograms of contained uranium-235 at any
one time. This condition does not specify the form of the uranium, therefore this matter
is no longer considered an apparent violation.
11.2 Unresolved Items
(Closed) URI 50-133/0501-01. As of January 31, 2005, the current location and
reportability of an unspecified number of fuel pellets last accounted for on June 7, 1976,
as stored in a vacuum bag hung from the side of SFP had not been determined.
The licensee determined based on interviews and other records reviewed that the June
1976 records of an unspecified number of fuel pellets that had been collected and
stored in a vacuum cleaner bag in the SFP was incorrect and that fuel pellets were not
stored in vacuum bags. After review of the licensees evaluation and as a result of an
independent interview conducted by the inspectors with the individual that lead the clean
up campaign in 1976, the inspectors agree with the licensees conclusion.
(Closed) URI 50-133/0501-02. As of January 31, 2005, the current location of the three
18-inch segments from irradiated fuel Assembly A-49, that was first reported missing by
Pacific Gas & Electric on July 16, 2004, had not been determined.
The licensee has completed their investigation and concluded that the location of the
missing 18-inch fuel segments can not be conclusively be determined. The licensee
believes that the most likely possibilities is that the fuel segments remain in the SFP but
in broken fragments or they were shipped to a low level waste site or NFS. The
inspectors concluded that the most likely location is at a low level waste site, but since
the actual location cannot be determined this matter is consider closed.
(Closed) URI 50-133/0501-06. The conditions that resulted in the loss of one complete
incore detector and parts of three others, their fate, and the consequences associated
with their loss has not been reviewed by the NRC.
The inspectors have concluded that the lost of the incore detectors constitute another
example of the three apparent violations identified above and would be so noted,
therefore this item is considered closed.
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12. Licensee Briefings and Exit Interview
The inspectors conducted briefings of preliminary inspection findings with licensee
senior plant managers at the conclusion of each site visit. On August 16, 2005, a
telephonic exit interview was conducted with senior licensee managers at the
conclusion of the NRC Special Inspection.
ATTACHMENT
SUPPLEMENTAL INSPECTION INFORMATION
PARTIAL LIST OF PERSONS CONTACTED
J. Albers, Radiation Protection Manager
M. Anthony, Decontamination Specialist
W. Barkhuff, Metallurgist Diablo Canyon
G. Bierbaum, Engineer
J. Brimble, Supervisor of Maintenance
T. Carraher, Data Logger
J. Galle, Sr. Design Engineer Manager
S. Gardner, Former Supervisor, Chem Nuclear
J. Hill, Inservice Inspectors Diablo Canyon
R. Johnson,
V. Jensen, Nuclear Quality Services Supervisor
P. Kapus, Document Reader
C. Kudla, SNM Control and Accountability Project
G. McKinnon, Control Operator
P. Narbut, Nuclear Quality Services Inspectors
B. Norton, Project Manager SNM Control and Accountability Project
R. Parker, Senior Radiation Protection Engineer
J. Rasmussen, Senior Control Operator
D. Swanson, Shift Foreman
M. Smith, Engineering Manager
D. Sokolsky, Supervisor of Licensing
S. Stevens, Document Reader
I. Tsosie, Radiation Protection Dosimetry Analyst
R. Willis, Plant Manager
INSPECTION PROCEDURES USED
IP 93812 Special Inspection
TI 2515/154 Spent Fuel Material Control and Accounting at Nuclear Power Plants
ITEMS OPENED, CLOSED, AND DISCUSSED
Opened
None
Discussed
50-133/0501-03 APV Contrary to the requirements of 10 CFR 74.19(a)(1), formerly 10
CFR 70.51(a)(1), from August 6, 1969 (date when assembly A-49
was shipped off site) to July 16, 2004 (date when PG&E
determined that the segments were missing), PG&E, failed to
keep records showing the inventory, transfer or disposal of three
approximately 18-inch segments of irradiated fuel containing
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approximately 22.5 grams of SNM. Also from June 25, 1973 to
February 4, 2005, the licensee failed to keep records including
location and unique identity showing the inventory, transfer or
disposal of one complete and three partial incore detectors
containing a total of approximately 0.035 grams of SNM.
50-133/0501-04 APV Contrary to the requirements of 10 CFR 74.19(b), formerly 10
CFR 70.51(b), from June 4, 1971 (date when last Type 1 fuel
assembly was shipped off site) to July 16, 2004 (date when PG&E
determined that the segments were missing), PG&E, a licensee
authorized by NRC License DPR-7 to possess SNM in a quantity
exceeding one effective kilogram, failed to establish, maintain,
and follow written material control and accounting procedures
sufficient to enable PG&E to account for the SNM in its
possession under license DPR-7. Specifically, PG&E failed to
account for SNM in a quantity of 111 grams of uranium-235,
27 grams of plutonium contained in remnants from Type 1
damaged fuel assemblies (fuel fragments and SNM waste), and
incore detectors.
50-133/0501-05 APV Contrary to the requirements of 10 CFR 74.19(c), formerly 10
CFR 70.51(c), Pacific Gas and Electric Company, failed to
conduct a physical inventory of all SNM in its possession at
intervals not to exceed 12 months. Specifically, inventories
performed by PG&E from June 4, 1971 (date when last Type 1
fuel assembly was shipped off site), to February 4, 2005, with the
exception of periods when the sealed SFP cover was in place, did
not include fuel fragments and other SNM remnants from Type 1
damaged fuel assemblies and all incore detectors.
Closed
50-133/0501-01 URI As of January 31, 2005, the current location and reportability of an
unspecified number of fuel pellets last accounted for on June 7,
1976, as stored in a vacuum bag hung from the side of SFP had
not been determined.
50-133/0501-02 URI As of January 31, 2005, the current location of the three 18-inch
segments from irradiated fuel Assembly A-49, that was first
reported missing by Pacific Gas & Electric on July 16, 2004, had
not been determined.
50-133/0501-06 URI The conditions that resulted in the loss of one complete incore
detector and parts of three others, their fate, and the
consequences associated with their loss has not been reviewed
by the NRC.
-3-
50-133/0501-07 APV From November 18, 2002, through September 10, 2004, the
licensee possessed SNM in the form of fuel fragments and was
not authorized by the technical specifications in effect at that time
to possess SNM in this form.
-4-
LIST OF ACRONYMS
BMI Battelle Memorial Institute
BWR Boiling Water Reactor
CFR Code of Federal Regulations
GE General Electric Company
HBPP Humboldt Bay Power Plant
IFI Inspection Followup Item
IP Inspection Procedure
IGSCC Intergranular Stress Corrosion Cracking
LER Licensee Event Report
LLRW Low Level Radioactive Waste
LSA Low Specific Activity
MC&A Material Control and Accounting
NRC Nuclear Regulatory Commission
NFS Nuclear Fuel Services
PG&E Pacific Gas and Electric Company
ODS Other Direct Shipment
R Roentgen
SFP Spent Fuel Pool
TI Temporary Instruction
TID Tamper Indicating Device
URI Unresolved Item
APV Apparent Violation
-5-
LIST OF SIGNIFICANT DOCUMENTS REVIEWED
Document Title Document Date
PG&E HBPP Visual Inspection Record of Type I (304 Stainless Clad) Nuclear Fuel September 7, 1966
Minutes of HBPP On-Site Review Committee of Special Meeting of September 17, 1968. September 17, 1968
(PG&E Record Locator No. 0210-4610)
PG&E General Computation Sheet Subject: Inner Can for fuel shipping Cask Sample to (Undated) Circa
Battelle Columbus (Undated)(PG&E Record Locator No. 3601-2912) September 17, 1968
Minutes of HBPP On-Site Review Committee of Special Meeting of October 2, 1968. October 2, 1968
(PG&E Record Locator No. 0210-4607)
PG&E General Computation Sheet Subject: NFS Shipping Cask (PG&E Record Locator August 5, 1969
No. 3612-2856)
HBPP Calculation NX-265, Evaluate Fuel Criticality with Assemblies Removed from Boral July 1, 2004
Cans, Revision 1
Event Notification No. 40877, Report of Missing Special Nuclear Material (Three Missing July 16, 2004
Fuel Rod Segments)
Event Notification No. 40961, Report of Missing Special Nuclear Material (Three Missing August 16, 2004
Fuel Rod Segments)
PG&E Letter HBL-04-020, Licensee Event Report (LER) 2004-001-00, Three Missing Fuel August 16, 2004
Rod Segments
PG&E Letter HBL-04-026, LER 2004-001-01, Three Missing Fuel Rod Segments, Rev. 1 November 19, 2004
PG&E Letter HBL-05-001, Special Nuclear Material Control and Accountability Project February 22, 2005
Interim Reports
PG&E Letter HBL-05-002, LER 2005-001-01, Missing Incore Detectors February 22, 2005
Event Notification No. 41430, Report of Missing Special Nuclear Material (Missing Incore February 22, 2005
Detectors)
HBPP Calculation NX-291, Estimation of SNM waste at HBPP, Revision 2 March 14, 2005
HBPP Calculation NX-287, SNM Re-verification, Revision 2 March 29, 2005
ATI Report Evaluation of Nuclear Fuel Rod Fragments and Inference to Fuel Rod A-49 at March 31, 2005
Humboldt Bay Power Plant
HBPP Calculation NX-288, Documentation of Spent Fuel Fragments and Debris, Rev. 6 April 21, 2005
HBPP Calculation NX-292, Develop Radioactive Waste Shipping Package Screening Tool April 29, 2005
for Possible Identification of Location of 18" Fuel Rod Segments from Fuel Assembly A-
49, Revision 1
HBPP Calculation NX-293, Evaluation of Underwater Dose Rates Associated with A-49 April 30, 2005
HBPP Calculation NX-290, To calculate and record the SNM Inventory, Revision 3 May 3, 2005
HBPP Calculation NX-289, Evaluate 18" Fuel Rod Segments from Fuel Assembly A-49, May 11, 2005
Revision 4
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LIST OF SIGNIFICANT DOCUMENTS REVIEWED
PG&E Letter HBL-05-017, Special Nuclear Material Control and Accountability Project May 27, 2005
Final Report
PG&E Letter HBL-05-019, LER 2005-001-01, Missing Incore Detectors, Revision 1 June 10, 2005
PG&E Letter HBL-05-020, LER 2004-001-02, Three Missing Fuel Rod Segments, Rev. 2 June 10, 2005
October 25, 2004 Enclosure 2 (ML042990566)
MEMORANDUM TO: D. Blair Spitzberg, Ph.D., Chief
Fuel Cycle Decommissioning Branch
Emilio M. Garcia, Health Physicist
Fuel Cycle Decommissioning Branch
FROM: Mark A. Satorius, Director /RA/
Division of Nuclear Materials Safety
SUBJECT: SPECIAL INSPECTION CHARTER - THREE SPENT FUEL ROD
SEGMENTS MISSING IN THE HUMBOLDT BAY SPENT FUEL
POOL
A NRC special inspection has been established in response to information received from PG&E
that three spent fuel rod segments are missing in the Humboldt Bay spent fuel pool. On
August 17, 2004, PG&E Humboldt Bay Power Plant informed the NRC Operations Center that
three spent fuel rod segments (approximately 18 inches in length) could not be located within
Humboldt Bays spent fuel pool in accordance with 10 CFR 74.11. PG&E also issued a press
release of the event on the same date. Personnel at Humboldt Bay Power Plant continue to
search the spent fuel pool for the missing segments and the licensee has begun an
investigation to determine what happened to them.
The NRC decided, based on a number of factors, that it is appropriate to charter a special
inspection to assess the key elements of PG&Es investigation effort. Key factors in this NRC
decision included the large scope and complexity of the licensees investigation, the need for
focused specialist oversight by NRC, and the need to evaluate potential generic implications.
The NRC decision recognizes that it is highly unlikely that the material is in the public domain.
The inspection will review the results of PG&Es investigation, assess PG&Es determination of
the root cause, determine whether PG&E was in compliance with applicable regulations,
complete Phase III of TI 2515/154, Spent Fuel Material Control and Accounting at Nuclear
Power Plants, and identify which findings or observations may have generic implications.
Focused oversight of the licensees investigation and search efforts for the missing fuel
fragments began on July 12, 2004. Additional inspector site visits occurred during the weeks of
August 9 and September 13, 2004. Results of these focused inspection visits will be issued as
a separate inspection report no later than early November 2004.
The special inspection is expected to be conducted during several weeks of onsite inspection to
review focused areas within the overall scope of the inspection and to continue to observe
licensee search activities. The special inspection will primarily consist of onsite activities but
may include some in-office activities. Each week of onsite inspection should utilize only the
inspector resources assigned to the areas to be- 7 reviewed
- during that weeks inspection. The
Memorandum to Various -2-
overall duration of the inspection will depend on PG&Es schedule for completion of its
investigation but it is currently anticipated that it could extend into 2005. For planning purposes,
it is expected that the onsite portion of the special inspection will be completed 30 days after the
issuance of PG&Es report documenting its investigation.
A draft of the inspection plan should be available for approval prior to the first onsite inspection
activity. Major revisions of the inspection plan should be discussed with me prior to
implementing the changes. An exit meeting, that is open for public observation, will be held
after the onsite and in-office inspection activities are completed. An inspection report will be
issued within 45 days following the exit meeting for the inspection.
The members of the special inspection team are:
Manager: Blair Spitzberg, Chief, FCDB
Leader: Emilio Garcia, Region IV
Members: Ray Kellar, Region IV
Martha Williams, NSIR
Other members will be assigned as needed.
The charter for the special inspection and details of the inspection scope are attached. The
special inspection shall be conducted in accordance with the applicable sections of Inspection
Procedure 93812, Special Inspection, and this memorandum.
Attachment: Special Inspection Charter
ATTACHMENT
CHARTER FOR HUMBOLDT BAY SPECIAL INSPECTION
BACKGROUND:
Humboldt Bay Power Plant Unit 3 is a shutdown 200-megawatt (thermal) (65-megawatt electric)
General Electric designed boiling water commercial nuclear power reactor. This reactor is
owned and was previously operated by Pacific Gas and Electric Company.
During the fall of 2003, Pacific Gas and Electric Company (PG&E) personnel at the Humboldt
Bay Power Plant Unit 3, were conducting an examination of the contents of the spent fuel pool
in preparation for dry storage operations. On November 12, 2003, Humboldt Bay personnel
discovered a fragment of a spent fuel pin approximately 4 inches long. Subsequent detailed
investigations identified additional fuel pin fragments in various spent fuel pool locations.
Humboldt Bay personnel informed the NRC via telephone of the discovery of the fuel
fragments.
In early December 2003, Humboldt Bay halted additional work in the spent fuel pool until a
criticality evaluation could be completed. Based on an NRC inspection performed during
January 2004, the Humboldt Bay Plant Manager initiated an evaluation of the amount of special
nuclear material present in each assembly and in the spent fuel pool.
On June 29, 2004, the licensee informed NRC staff that it had recently found documentation
indicating that in 1968, a fuel pin was segmented into three 18-inch sections intended to be sent
offsite for an experiment. Documentation also indicated that the three segments had been
placed into a 1.5-inch diameter pipe and subsequently returned to the spent fuel pool after the
intended experiment had been canceled. Humboldt Bay personnel started a search of the
spent fuel pool for the three fuel rod segments on July 9, 2004.
On July 16, 2004, PG&E notified the NRC of a discrepancy between inventory records and the
location of the three missing spent fuel rod segments (Event Notification #40877). The licensee
continued to perform a search for the fuel pin segments in the most likely and accessible
locations in the spent fuel pool and perform a search of documents that could provide
information as to the whereabouts of the fuel segments. Interviews were conducted with
personnel that worked at the plant during the time frame when the fuel pin was segmented.
On August 16, 2004, PG&E issued a 30-day written followup report to the initial July 16, 2004,
notification. This report was made pursuant to 10 CFR 20.2201(b)(2)(ii).
On August 17, 2004, the licensee Plant Staff Review Committee determined that the fuel
segments were not in the most likely and accessible locations within the spent fuel pool.
Consequently, PG&E made a 1-hour notification to the NRC pursuant to 10 CFR 74.11(a) that
the missing fuel rod segments were considered lost.
PG&E personnel have entered into Phase II of the search for the missing fuel rod segments.
The Phase II search includes additional searches of the spent fuel pool in less accessible
locations, additional document searches and personnel interviews. NRC inspectors continue to
provide periodic oversight of the investigation process. The licensee still believes that the most
likely location of the missing fuel rod segments is in the spent fuel pool. The licensees
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investigation team will evaluate the potential for offsite disposal of the fuel segments and
complete a root cause analysis including documentation of the team findings in a final report.
PG&E expects to complete the search for the missing fuel rod segments and root cause
investigation during the first quarter of 2005.
On September 29, 2004, a Category 1 Public Meeting was held with Pacific Gas and Electric
Company. The purpose of this meeting was to discuss licensed radioactive material control
and accountability at Humboldt Bay Power Plant.
SPECIAL INSPECTION CHARTER
A special inspection will evaluate PG&Es investigation and conclusions regarding the potential
location of the missing fuel rod segments. The special inspection may consist of several
inspections that occur during the course of PG&Es investigation. The special inspection should:
13. Conduct a thorough and systematic review of PG&Es investigation into the
circumstances that led to the loss of accountability of the three missing fuel rod
segments and other special nuclear material (SNM). Determine the adequacy of
PG&Es investigation and conclusions regarding the location of the three missing fuel
rod segments, based upon its completeness and thoroughness of fuel pool inspections,
records reviews, and interviews.
14. Assess the adequacy of PG&Es control of SNM and non-SNM radiological materials.
15. Assess the determination of root cause performed by PG&E. Identify alternative causes
if appropriate. Develop independent conclusions regarding the causes(s) of the loss of
accountability of the special nuclear material.
16. Assess the adequacy of PG&Es investigation regarding its conclusion on the accuracy
of the accountability for the remainder of the special nuclear material in the spent fuel
pool.
17. Independently verify selected sets of records and interviews.
18. Determine whether PG&E was in compliance with applicable regulations.
19. Assess the adequacy of PG&Es radiological characterization of each missing fuel rod
segment.
20. Complete Phase III of TI2515/154, Spent Fuel Material Control and Accounting at
Nuclear Power Plants.
21. Conduct regular briefings for NRC internal stakeholders to allow the appropriate NRC
internal stakeholders to brief external stakeholders.
22. Identify those findings or observations that may have generic implications.
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23. Document the inspection findings, observations and conclusions in a special inspection
report in accordance with the applicable sections of IP 93812 within 45 days of the exit
meeting.
24. Conduct an inspection exit that is open for public observations.