ML081690841
| ML081690841 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 06/17/2008 |
| From: | Spitzberg D Division of Nuclear Materials Safety IV |
| To: | Parrish J Energy Northwest |
| References | |
| EA-08-183 IR-08-007 | |
| Download: ML081690841 (21) | |
See also: IR 05000397/2008007
Text
June 17, 2008
J. V. Parrish
Chief Executive Officer
Energy Northwest
P.O. Box 968 (Mail Drop 1023)
Richland, Washington 99352-0968
SUBJECT:
INSPECTION REPORT NOS 050-397/08-007; 072-035/08-001 AND
Dear Mr. Parrish:
This refers to the inspection conducted from April 14 through May 19, 2008, at the Columbia
Generating Station. The purpose of the initial onsite inspection conducted April 14-17, 2008, was
to perform a routine operational inspection of the Independent Spent Fuel Storage Installation
(ISFSI) and to follow up on the hydrogen burn event that occurred during canister closure welding
operations on April 8, 2008. Following implementation of corrective actions designed to prevent
recurrence, a second hydrogen burn event occurred during the inspection on April 16, 2008.
Your staff determined that the best course of action was to secure the canister in a safe
configuration and bring in outside industry resources to determine the cause(s) of the hydrogen
burn events and implement additional actions to prevent recurrence. A debrief was conducted
with members of your staff on April 17, 2008. The inspection remained open as your staff
conducted a Technical Issues Resolution Process to determine the cause of the hydrogen burn
events and actions to prevent recurrence. Following changes to your welding process, the
Resident Inspector observed the welding operations on canister serial numbers 169 and 170,
which occurred without further incident on April 26 and May 1, 2008, respectively. A telephonic
exit was conducted with Mr. Tom Lynch and other members of your staff on May19, 2008. The
enclosed report presents the results of the inspection.
This inspection was an examination of activities conducted under your license as they relate to
safety and compliance with the Commissions rules and regulations and with the conditions of
your license. Within these areas, the inspection included reviews of the hydrogen burn events,
selected examination of procedures and representative records, observations of activities, and
interviews with selected personnel.
Based on the results of the inspection, the NRC has determined that a Severity Level IV violation
of NRC requirements occurred. The violation was evaluated in accordance with the NRC
Enforcement Policy included on the NRCs website at www.nrc.gov/about-
nrc/regulatory/enforcement/enforce-pol.html.
UNITED STATES
NUCLEAR REGULATORY COMMISSION
R E GI ON I V
612 EAST LAMAR BLVD, SUITE 400
ARLINGTON, TEXAS 76011-4125
Energy Northwest
- 2 -
The violation is cited in the enclosed Notice of Violation (Notice) and the circumstances
surrounding it are described in detail in the subject inspection report. Consistent with Section VI.A
of the Enforcement policy, the violation is being cited in the Notice because the licensee failed to
restore compliance within a reasonable time after a noncompliance was identified.
In addition, the NRC has determined that one additional Severity Level IV violation of NRC
requirements occurred. This violation is being treated as a Non-Cited Violation (NCV),
consistent with Section VI.A of the Enforcement policy. The NCV is described in the subject
inspection report.
You are required to respond to this letter, as it pertains to the Notice described above, and should
follow the instructions specified in the enclosed Notice when preparing your response.
In addition, if you contest the violation or significance of the NCV, you should provide a response
within 30 days of the date of this inspection report, with the basis for your denial, to the Nuclear
Regulatory Commission, ATTN: Document Control Desk, Washington DC 20555-0001, with
copies to: the Regional Administrator, NRC Region IV; the Director, Office of Enforcement,
United States Nuclear Regulatory Commission, Washington, DC 20555-0001; and Mr. Zachary
Dunham, Senior Resident Inspector at Columbia Generating Station. The NRC will use your
response, in part, to determine whether further enforcement action is necessary to ensure
compliance with regulatory requirements.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its
enclosures, and your response will be available electronically for public inspection in the NRC
Public Document Room or from the NRC's document system (ADAMS). ADAMS is 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/
D. Blair Spitzberg, Ph.D., Chief
Repository and Spent Fuel Safety Branch
Docket: 50-397
License: NPF-21
Enclosures:
2. NRC Inspection Report 050-0397/08-007; 072-0035/08-001
w/Attachments
Energy Northwest
- 3 -
cc: w/enclosures
Chairman
Energy Facility Site Evaluation Council
P.O. Box 43172
Olympia, WA 98504-3172
Gregory V. Cullen
Manager, Regulatory Programs
Energy Northwest
P.O. Box 968, Mail Drop PE20
Richland, WA 99352-0968
Chairman
Benton County Board of Commissioners
P.O. Box 190
Prosser, WA 99350-0190
William A. Horin, Esq.
Winston & Strawn
1700 K Street, NW
Washington, DC 20006-3817
Matt Steuerwalt
Executive Policy Division
Office of the Governor
P.O. Box 43113
Olympia, WA 98504-3113
Lynn Albin
Washington State Department of Health
P.O. Box 7827
Olympia, WA 98504-7827
Technical Services Branch Chief
FEMA Region X
130 228th Street S.W.
Bothell, WA 98201-9796
Ken Niles
Assistant Director
Nuclear Safety and Energy Siting Division
Oregon Department of Energy
625 Marion Street NE
Salem, OR 97301-3742
Energy Northwest
- 4 -
Special Hazards Program Manager
Washington Emergency Management Division
127 W. Clark Street
Pasco, WA 99301
Mike Hammond
Department of Homeland Security
FEMA/REP
130 228th Street S.W.
Bothell, WA 98201-9796
Energy Northwest
- 5 -
DISTRIBUTION:
Regional Administrator (Elmo.Collins@nrc.gov)
DRA (Chuck.Casto@nrc.gov)
RC/ACES TL (Karla.Fuller@nrc.gov)
SES (Michael.Vasquez@nrc.gov)
DNMS Director (Art.Howell@nrc.gov)
DRP Director (Dwight.Chamberlain@nrc.gov)
DRS Director (Roy.Caniano@nrg.gov)
Senior Resident Inspector (Zachary.Dunham@nrc.gov)
Resident Inspector (Ronald.Cohen@nrc.gov)
Branch Chief, DRP/A (Claude.Johnson@nrc.gov)
RSFS Inspector (Ray.Kellar@nrc.gov)
RITS Coordinator (Marisa.Herrera@nrc.gov)
SFST Senior Inspector (Robert.Temps@nrc.gov)
SFST Senior Project Manager (Randy.Hall@nrc.gov)
Columbia Site Secretary (Crystal.Myers@nrc.gov)
Alexander.Sapountzis@nrc.gov
Nick.Hilton@nrc.gov
ROPreports
SUNSI Review Completed: RLK ADAMS: Yes
No Initials: RLK
Publicly Available Non-Publicly Available Sensitive Non-Sensitive
S:\\DNMS\\!FCDB\\!RLK\\CGS72-0801RLK.doc
RIV:DNMS/RSFS
DRP/
NMSS/SFST SFST
ACES
D:DNMS
C:RSFS
RLKellar
RBCohen
JRHall
RTemps
GMVasquez ATHowell
DBSpitzberg
/RA/
E-VJEverett
E-RLKellar
E-RLKellar
E-RLKellar /RA/
/RA/
6/16/08
6/10/08
6/16/08
6/16/08
6/16/08
6/17/08
6/16/08
OFFICIAL RECORD COPY T=Telephone E=E-mail F=Fax
Enclosure 1
Energy Northwest
Docket Nos. 050-00397; 072-00035
Columbia Generating Station
License No. NPF-21
During an NRC inspection conducted from April 14 through May 19, 2008, a violation of NRC
requirements was identified. In accordance with the NRC Enforcement Policy, the violation is
listed below:
10 CFR 72.210 provides, in part, a general license for the storage of spent fuel in an
independent spent fuel storage installation (ISFSI) at power reactor sites, to persons
authorized to operate nuclear power reactors under 10 CFR Part 50. This general
license is limited to storage of spent fuel in casks approved under the provisions of
Certificate of Compliance (CoC) 1014, for the HI-STORM Cask System was issued in
accordance with 10 CFR 72.238. The certificate states, in part, that it is conditional upon
fulfilling the requirements of 10 CFR Part 72, as applicable, and the attached Appendix A
(Technical Specification) and Appendix B (Approved Contents and Design Features).
Section 3.8 of CoC 1014, Appendix B, requires, in part, that during the Multi-Purpose
Canister (MPC) lid-to-shell welding operations, combustible gas monitoring of the space
under the MPC lid be performed to ensure that no combustible gas mixture is present in
the welding area.
Contrary to the above, on April 8, 2008, and again on April 16, 2008 the licensee did not
effectively monitor combustible gas concentrations under the MPC lid during the MPC
lid-to-shell welding operations to ensure that no combustible gas mixture was present in
the welding area. Specifically, on April 8, 2008, after the root pass of the lid-to-shell weld
had been completed and work was being done on the next weld layer, the licensee
elected to suspend combustible gas concentration monitoring; and on April 16, 2008, the
position of the licensees explosive gas monitor relative to the MPC vent port did not
effectively detect combustible gas concentrations. Both of these situations resulted in
hydrogen burn events.
This is a Severity Level IV violation (Supplement VI).
Pursuant to the provisions of 10 CFR 2.201, Energy Northwest is hereby required to submit a
written statement or explanation to the U.S. Nuclear Regulatory Commission, ATTN: Document
Control Desk, Washington, DC 20555-0001 with a copy to the Regional Administrator,
Region IV, and a copy to the NRC Resident Inspector at the facility that is the subject of this
Notice, within 30 days of the date of the letter transmitting this Notice of Violation (Notice). This
reply should be clearly marked as a "Reply to a Notice of Violation; EA-08-183," and should
include for each violation: (1) the reason for the violation, or, if contested, the basis for disputing
the violation or severity level, (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.
Enclosure 1
- 2 -
If an adequate reply is not received within the time specified in this Notice, an order or a Demand
for Information may be issued as to why the license should not be modified, suspended, or
revoked, or why such other action as may be proper should not be taken. Where good cause is
shown, consideration will be given to extending the response time.
If you contest this enforcement action, you should also provide a copy of your response, with the
basis for your denial, to the Director, Office of Enforcement, United States Nuclear Regulatory
Commission, Washington, DC 20555-0001.
Because your response 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 www.nrc.gov/reading-rm/pdr.html or www.nrc.gov/reading-rm/adams.html, to the
extent possible, it should not include any personal privacy, proprietary, or safeguards information
so that it can be made available to the public without redaction. If personal privacy or proprietary
information is necessary to provide an acceptable response, then please provide a bracketed
copy of your response that identifies the information that should be protected and a redacted
copy of your response that deletes such information. If you request withholding of such material,
you must specifically identify the portions of your response that you seek to have withheld and
provide in detail the bases for your claim of withholding (e.g., explain why the disclosure of
information will create an unwarranted invasion of personal privacy or provide the information
required by 10 CFR 2.390(b) to support a request for withholding confidential commercial or
financial information). If safeguards information is necessary to provide an acceptable response,
please provide the level of protection described in 10 CFR 73.21.
In accordance with 10 CFR 19.11, you may be required to post this Notice within two working
days.
Dated this 17th day of June 2008
Enclosure 2
- 1 -
ENCLOSURE
U. S. NUCLEAR REGULATORY COMMISSION
REGION IV
Docket Nos:
050-00397; 072-00035
License No.:
Report Nos.:
050-0397/08-007; 072-0035/08-001
Licensee:
Energy Northwest
Facility:
Columbia Generating Station
Location:
Richland, Washington
Dates:
April 14 through May 19, 2008
Inspectors:
Ray Kellar, P.E., ISFSI Inspector, Repository and Spent Fuel Safety Branch
Ron Cohen, Resident Inspector, Projects Branch A
Approved By:
D. Blair Spitzberg, Ph.D, Chief
Repository and Spent Fuel Safety Branch
Attachments:
Supplemental Information
Loaded HI-STORM 100S Casks at the Columbia Generating Station ISFSI
Enclosure 2
- 2 -
EXECUTIVE SUMMARY
Columbia Generating Station
NRC Inspection Report Nos. 050-0397/08-007; 072-0035/08-001
An inspection of the Columbia Generating Station (CGS) Independent Spent Fuel Storage
Installation (ISFSI) facility in Richland, Washington was conducted from April 14, 2008 through
May 19, 2008. A routine operational inspection of ISFISI activities was conducted to verify that
the ISFSI was being maintained in compliance with the applicable requirements of the Certificate
of Compliance (CoC), Final Safety Analysis Report (FSAR), and 10 CFR Part 72. Additionally, a
follow up inspection of the hydrogen burn event that had occurred during the welding operations
on April 8, 2008, was arranged. A second hydrogen burn event occurred on April 16, 2008,
during the routine operational inspection. The licensee determined that the best course of action
was to secure the canister in a safe configuration and bring in outside industry resources to
determine the cause(s) of the hydrogen burn events and implement actions to prevent
recurrence. A debrief was conducted with the licensee on April 17, 2008. The inspection
remained open as the licensee conducted a Technical Issues Resolution Process to determine
the cause of the hydrogen burn events and actions to prevent recurrence. Following changes to
the welding process, the Resident Inspector observed the welding operations on canister serial
numbers 169 and 170, which occurred without further incident on April 26 and May 1, 2008,
respectively.
Operation of an ISFSI (60855.1)
Two hydrogen burn events occurred during welding of the MPC lid-to-shell welds on
canister serial numbers 168 and 169. During the welding operations for canister serial
number 168 the licensee elected to suspend combustible gas monitoring after the
completion of the root pass weld. A hydrogen ignition event occurred on this canister
after the suspension of the combustible gas monitoring. Following this event the licensee
implemented procedure changes to require combustible gas monitoring during the entire
MPC lid-to-shell weld process. Despite this and other corrective actions, the combustible
gas monitoring configuration was ineffective in determining the presence of combustible
gases and a second hydrogen burn event occurred during welding operations on the next
canister loaded, MPC canister serial number 169. Following the second hydrogen burn
event, the licensee placed the MPC in a safe configuration and brought in individuals with
outside industry experience to determine the causes of the hydrogen burn events and
determine corrective actions to prevent recurrence. The licensee implemented changes
to introduce an inert gas (argon) beneath the MPC lid during the lid-to-shell welding
process and to relocate the explosive gas monitor sampling point to the vicinity of the
MPC vent port. The completion of the MPC lid-to-shell weld on canister serial
numbers 169 and 170 occurred without further incident. A Notice of Violation is being
issued, consistent with Section VI.A.1 of the NRC Enforcement Policy for failure to
monitor combustible gas concentrations during the MPC lid-to-shell weld. (Section 1.2.a)
The licensee procedures contained sufficient information to select and load spent fuel
assemblies into storage in compliance with CoC, Appendix B requirements. Selected fuel
assemblies were verified by the inspector to meet the CoC, Appendix B requirements.
(Section 1.2.b)
Enclosure 1
- 3 -
The licensee was performing radiological surveys of canister contamination and cask
dose rates in accordance with the Technical Specification requirements. Result of
surveys performed for selected canisters and casks were well below the Technical
Specification limits. (Section 1.2.c)
The licensee was meeting the Technical Specification requirements for daily monitoring of
temperature readings of the cask outlet vents and ambient air. All of the selected daily
temperature readings reviewed were found to be below the Technical Specification and
licensee specified maximum temperature limits. (Section 1.2.d)
The ISFSI related condition reports sampled from the licensees corrective action system
adequately addressed the identified deficiencies and provided appropriate corrective
actions. (Section 1.2.e)
The licensee was meeting the requirements of 10 CFR 72.176 for conducting periodic
audits of the ISFSI program. Deficiencies discovered during the audits were entered into
the licensee corrective action program for evaluation, as appropriate. (Section 1.2.f)
72.48 Evaluations (60857)
The licensee 10 CFR 72.48 screenings and the single 10 CFR 72.48 evaluation had been
performed in accordance with the requirements of 10 CFR 72.48(c). However, the
licensee did not perform a 10 CFR 72.48(c) review of the changes to the written
evaluations contained in Section 1.1.2 of the Energy Northwest Independent Spent Fuel
Storage Installation 10 CFR 72.212 Evaluation, as required by 10 CFR 72.212(b)(2)(ii).
This violation is being treated as a Non-Cited Violation, consistent with Section VI.A.1 of
the NRC Enforcement Policy. (Section 2.2)
Follow-up (IP 92701)
Inspection Follow-up Item (IFI) 72-35/0401-01 associated with the review of
10 CFR 72.212(b) changes necessary to support the inclusion of the hydrogen water
chemistry project has been closed in this inspection report. The licensees analysis
indicated that the existing explosion hazards analysis, which considered the probability of
a projectile impacting the HI-STORM cask during transportation or storage, was not
altered by the inclusion of the hydrogen water chemistry project. (Section 3)
Enclosure 1
- 4 -
REPORT DETAILS
Summary of Facility Status
Columbia Generating Station is a General Electric boiling water reactor owned by Energy
Northwest. The facility is located approximately 12 miles northwest of Richland, Washington, on
the Department of Energys Hanford Reservation. Energy Northwest selected the Holtec HI-
STORM 100S cask system for storage of their spent fuel. The licensee was loading spent fuel
under the general license requirements of Certificate of Compliance (CoC) 1014, Amendment 2.
The initial Independent Spent Fuel Installation (ISFSI) loading campaign was completed in
December 2002 and consisted of five casks. The second loading campaign was completed in
April of 2004 and consisted of ten casks. The third spent fuel loading campaign was in progress
at the time of the inspection and consisted of 12 additional casks. The inspectors witnessed
portions of the loading operations associated with Multi-Purpose Canister (MPC) serial
numbers 168 and 169 during the third loading campaign.
1
Operation of an ISFSI (60855.1)
1.1
Inspection Scope
An inspection of the Columbia Generating Station ISFSI was conducted to verify the
licensee was operating the ISFSI in conformance with the requirements of the CoC, the
Final Safety Analysis Report (FSAR) and 10 CFR Part 72. Portions of licensee activities
associated with fuel selection, radiological surveillances, heat removal surveillances,
corrective actions and Quality Assurance audits were reviewed during the inspection. The
inspection of the hydrogen burn events and corrective actions taken by the licensee were
also reviewed.
1.2
Observations and Findings
a.
Hydrogen Burn Events
The potential for a hydrogen burn to occur during canister closure welding operations was
first communicated by the NRC to licensees in 1996, using NRC Bulletin 96-04 and
Information Notice 96-34. Hydrogen can be produced during loading operations by
radiolysis of the water surrounding the loaded fuel assemblies and the passivation of the
aluminum neutron absorbers exposed to water in the canister. Once the canister cavity is
drained, dried, and backfilled with helium, the source of the hydrogen gas is eliminated.
A hydrogen burn event occurred at approximately 2:45 pm on April 8, 2008, during loading
operations for MPC serial number 168. The hydrogen burn event occurred during the
welding operations on the seventh canister that had been loaded with spent fuel during
the current CGS canister loading campaign. The root pass of the lid-to-shell weld had
been completed. The welders were working on the next weld layer using a hot wire pass
and had completed approximately one-half of the lid circumferential weld using two weld
heads when the first hydrogen burn event occurred. The hydrogen burn caused the vent
and drain port covers to be blown off the MPC lid and relocated several inches away.
Approximately a quart of water from the MPC drain port was ejected and deposited on the
MPC lid.
Enclosure 1
- 5 -
The licensee stopped the welding operations and placed the canister in a safe condition.
The licensee was using Procedure 6.6.7, MPC Processing, Revision 17 to control the
installation activities. The revision of Procedure 6.6.7 in use allowed the cask loading
supervisor to stop the venting and combustible gas monitoring after the root pass of the
lid-to-shell weld had been completed. Consistent with this procedure, the licensee had
stopped venting and monitoring of the combustible gas concentration after the root pass
weld had been completed. The licensee determined that a hydrogen burn event had
occurred during the lid-to-shell welding operations. After reestablishing the combustible
gas monitoring for explosive gas concentrations in the MPC, the licensee completed the
lid-to-shell weld for canister serial number 168 without further incident.
Section 3.8 of CoC 1014, Appendix B, Approved Contents and Design Features,
required in part that during the MPC lid-to-shell welding operations, combustible gas
monitoring of the space under the MPC lid be performed to ensure that no combustible
gas mixture is present in the welding area. Contrary to this requirement, on April 8, 2008,
the licensee process did not monitor combustible gas concentrations under the MPC lid
during the full duration of the MPC lid-to-shell welding operations of MPC serial number
168. This was identified as a violation of Section 3.8 of CoC 1014, Appendix B.
Following the hydrogen event on April 8, 2008, the licensee determined that the area
beneath the MPC lid needed to be continuously vented and monitored for explosive gases
during the welding of the lid-to-shell weld. The licensee implemented corrective actions in
Revision 19 to Procedure 6.6.7 to require continuous venting and combustible gas
monitoring during the lid-to-shell weld. A clear tygon hose was firmly attached to the
canister vent port and routed to a receiving tank. Another hose was routed from the
receiving tank to the inlet of the explosive gas monitor during the welding operations.
Following implementation of corrective actions from the first hydrogen burn event, a
second hydrogen burn event occurred on April 16, 2008, at approximately 11:58 pm,
during welding operations of the hot wire layer on MPC serial number 169. Similar to the
first hydrogen burn event, the root pass weld had been completed and the hot wire weld
layer pass was in process at the time of the event. The second hydrogen burn event
caused the tygon hose on the vent port and the drain port cover plate to be blown off and
water from the MPC drain line was deposited on the MPC lid.
The NRC inspector was informed of the second hydrogen burn event and arrived onsite at
approximately 2:00 am on April 17, 2008. The inspector observed that the explosive gas
monitor was in place and that the monitor indicated that no explosive gas was present.
The inspector questioned the CGS supervisor as to whether the existing configuration of
the explosive gas monitor would detect explosive gases and the supervisor took a spare
calibrated monitor to the MPC vent port to check for the presence of an explosive
atmosphere. The monitor read off scale high on explosive gases when exposed to the
MPC vent port. The supervisor then removed the explosive gas monitor that was
configured to detect the presence of explosive gases from the MPC vent port, which also
registered off scale high on explosive gases when exposed directly to the MPC vent port.
The licensee secured the MPC in a safe condition and proceeded to determine the next
course of action to be taken.
Enclosure 1
- 6 -
As previously stated, Section 3.8 of CoC 1014, Appendix B, required that during the MPC
lid-to-shell welding operations, combustible gas monitoring of the space under the MPC
lid was required to ensure that there was no combustible gas mixture present in the
welding area. Contrary, to the above requirement, on April 16, 2008, the licensee system
configuration did not effectively monitor combustible gas concentrations under the MPC
lid which contributed to a second hydrogen burn event. This is a violation of Section 3.8
of CoC 1014, Appendix B. This violation is being treated as a cited violation, consistent
with Section VI.A.1 of the NRC Enforcement Policy.
Following the second occurrence of a hydrogen burn, the licensee suspended loading
operations and commenced recirculation of water from the spent fuel pool through the
MPC. Individuals with outside industry experience arrived on site to assist in the
determination of the cause of the hydrogen burn events and determine the best method to
prevent recurrence. The team performed a root cause analysis utilizing change analysis
and barrier analysis methods. The Summary Report Hydrogen Burn Event was still in
draft form at the time this inspection report was prepared, however the licensee had
decided to introduce an inert gas (argon) beneath the MPC lid during the lid-to-shell
welding process to prevent recurrence. The licensee also relocated the explosive gas
monitor sampling point to the vicinity of the MPC vent port. As part of the licensees
corrective actions, Procedure 6.6.7 was revised to include directions on how to introduce
the inert gas into the MPC void area and how to monitor for explosive gases in
Attachment 9.14, Combustible Gas Monitoring and Purging, Revision 20.
An evaluation of the potential impact of the bounding hydrogen burn event on the spent
fuel assemblies and the spent fuel canister was performed by the dry fuel cask vendor.
The calculated pressure increase that occurred during the hydrogen burn event was
determined to be less than 1.0 psi, which is a small fraction of the normal design pressure
of the MPC (100 psi) or the spent fuel rods (in excess of 1,000 psi). Therefore, the
integrity of the MPC and the spent fuel assemblies was unaffected by the hydrogen burn
events.
On April 26, 2008 the inspectors witnessed the resumption of welding operations by
Energy Northwest personnel on MPC serial number 169. The inspectors reviewed the
revised hydrogen purge and monitoring process as part of the Procedure 6.6.7,
Revision 20. The inspectors observed the hydrogen purge gas setup and implementation
and the process used by the licensee to monitor for explosive gases during the welding
process. The inspectors concluded that the procedures had been adequately revised and
that the installation activities were completed without any recurrence of the of the previous
hydrogen burn events. Additionally, the inspectors made similar observations of the
welding operations on MPC serial number 170 on May 1, 2008 with the same
conclusions.
b.
Fuel Selection
The MPC-68 canister fuel parameters are specified in the Holtec CoC 1014, Appendix B,
Section 2.0, Approved Contents. The fuel assemblies that had been loaded into
canister serial numbers 162 (cask 16), 164 (cask 18) and 166 (cask 20) were selected for
review by the inspector and compared against the requirements located in the CoC.
Enclosure 1
- 7 -
The licensee utilized several procedures to document the fuel selection process, fuel
loading process and to provide verification that the fuel assemblies had been placed in
the correct canister cell location. Procedure 9.6.1, Spent Fuel Selection for Cask
Storage, Revision 2 had been used to select the fuel assemblies for loading during the
current cask campaign. Procedure 9.6.1 had been revised to include the fuel selection
requirements contained in CoC 1014, Amendment 2.
Procedure 9.6.1, Attachment 9.3, Cask Loading Plan, included locations for the preparer
and reviewer to document that the fuel assemblies selected for loading met the CoC
Appendix B requirements. The attachment also specified the MPC canister storage cell
where the fuel assembly was to be placed. The attachments for canister serial
numbers 162, 164 and 166 were reviewed by the inspector and were found to have been
signed by the preparer and reviewer as meeting the CoC Appendix B requirements.
Procedure 6.3.40, Determination of Fuel Assembly Condition for ISFSI, Revision 4,
provided the procedural guidance to ensure that selected fuel assemblies met the CoC
definition of intact fuel, consisting of no known or suspected cladding defects greater than
pinhole leaks or hairline cracks. The inspector reviewed the criteria contained in the
procedure as well as supplemental fuel sipping data contained in Calculation NE-02-00-
08, Revision 1, which documented which discharged spent fuel assemblies were suspect
and flagged as lacking documentation to meet the CoC definition of intact fuel. All of the
fuel assemblies from cycle 3 and 4 were suspect as well as four fuel assemblies from
cycle 5 and one fuel assembly from cycle 15. There were also 45 fuel assemblies that
were discharged from cycle 5 that were suspect. The inspector reviewed a sampling of
fuel assemblies to be loaded in canister serial numbers 162, 164 and 166 and determined
that the licensee had not selected any of the suspect fuel assemblies that lacked sufficient
documentation as meeting the definition of intact fuel for loading into the selected
canisters.
Procedure 6.6.15, Fuel Handling and Refuel Activities Procedures, Revision 5 was used
to verify that the fuel assembly that had been selected for placement by Procedure 9.6.1
had been placed in the correct MPC canister cell. Page 11 of Procedure 6.6.15 required
the signature of the preparer and reviewer that performed the verification of each fuel
assembly serial number by MPC cell location. The inspector reviewed the documentation
for canister serial numbers 162, 164 and 166 and determined that all assemblies had
been documented as being installed in the correct canister cell.
c.
Radiological Surveillances
The Holtec Technical Specifications included bounding requirements for levels of
contamination and radiological dose levels on the canisters and casks. The inspector
reviewed the licensee documentation of the dose rate surveys performed on selected
HI-STORM and of selected contamination level surveys performed on the HI-TRAC
transfer cask and the canisters.
Technical Specification 3.2.2 required the removable contamination on the exterior
surfaces of the transfer cask and the accessible portions of the canister not to exceed
1,000 disintegrations per minute (dpm) per 100 square centimeters from beta and gamma
sources and 20 dpm/100 square centimeters from alpha sources.
Enclosure 1
- 8 -
Procedure HSP-SFS-C102, Transfer Cask Surface Contamination, Revision 2 provided
directions for obtaining contamination surveys of the HI-TRAC transfer cask and the
accessible portions of the MPC. The contamination smears were counted for alpha and
beta-gamma contamination. The results for each MPC were recorded in Attachment 9.1.
The inspector reviewed the results of the contamination smears for canister serial
numbers 162, 164 and 166. All the documentation indicated that the smears were below
the required Technical Specification limits of 1,000 dpm/100 square centimeters from beta
and gamma sources and 20 dpm/100 square centimeters from alpha sources.
Technical Specification 5.7.8 required dose rates to be measured at the HI-STORM cask
inlet and outlet vent screens, on the cask top and on the sides of the cask. The measured
surface dose rates (gamma + neutron) were required to be below the licensees site-
specific surface dose rate limit. In the case of the cask top and sides, additional upper
limits were imposed of 20 mrem/hour for the cask top and 110 mrem/hour for the cask
sides.
The inspector reviewed the licensee documentation for the HI-STORM dose rate
measurements taken on the concrete casks containing canister serial numbers 162, 164,
and166. The HI-STORM surface dose rate measurements were documented in
Procedure HSP-SFS-C103, Overpack Average Surface Dose Rate, Revision 3. The
calculated site-specific HI-STORM dose rates for the sides, top and vent ducts were
included in Attachment 9.2, HI-STORM Surface Dose Rates Data Sheet. The measured
HI-STORM dose rates for canister serial numbers 162, 164 and 166 were all well below
the site-specific surface dose rate limits. Additionally, the site-specific dose rate limits for
the HI-STORM top and sides were well below the upper limits imposed by the Technical
Specifications of 20 mrem/hour and 110 mrem/hour, respectively.
d.
Heat Removal Surveillances
Holtec Technical Specification 3.1.2.1 required the licensee to either verify that all the
storage cask inlet and outlet air ducts were free from blockage every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or for
storage casks with installed temperature monitoring equipment, verify that the difference
between the average storage cask air outlet temperature and the ISFSI ambient
temperature was less than or equal to 126 degrees Fahrenheit every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The
licensee had elected to monitor the cask temperatures in lieu of inspecting the inlet and
outlet ducts.
The inspector selected the licensee cask temperature records for the months of July 2006
and December 2007 for review. Procedure OSP-SFS-D101, Spent Fuel Storage Cask
Heat Removal System Daily Checks, Revisions 6 through 9 had been used to document
the daily temperatures. The licensee had specified a more conservative cask outlet
temperature difference of 114 degrees Fahrenheit in Procedure OSP-SFS-D101. All of
the daily temperature readings from the selected months were reviewed and found to be
less than the licensee specified 114 degree Fahrenheit temperature difference between
the cask outlet vent temperatures and the ambient air temperatures.
Enclosure 1
- 9 -
e.
Corrective Actions
The licensee prepared a list of the ISFSI related condition reports that had been
generated since the last NRC inspection in April 2004. The inspector selected nine of the
condition reports for review. The condition reports reviewed by the inspector were:
Condition Report No.
Condition Report Description
21608
Smears should be taken before decontamination of casks
21673
MPC Lid would not fully seat into MPC
22279
Casks 8-15 do not have temperature monitoring
22377
In-process documents storage not meeting QA program
35087
OE-Hatch crawler found to have damaged lift towers
40558
Daily screen checks are performed outside of ISFSI fence
41190
Maintenance procedures require 10 CFR 72.48 screens
176686
Lack of procedural guidance for snow blocking ISFSI vents
179373
Lead snakes identified on MPC to be downloaded
The inspector determined that the corrective actions associated with the listed condition
reports and associated deficiencies appeared to have been appropriately addressed by
the licensee. No additional findings were identified.
f.
Quality Assurance Audits
Two Quality Assurance Audits of the ISFSI program had been performed by the licensee
since the last NRC inspection completed on March 31, 2004. Audit Report AU-DC-04,
documented the audit that had been conducted during the second cask loading campaign
from April 19 to May 13, 2004. Audit Report AU-DC-06 included observations that had
been conducted from April 6 to May 11, 2006. The audit teams had identified several
ISFSI program weaknesses and had initiated Condition Reports (CRs) and Problem
Evaluation Requests (PERs).
The inspector reviewed Procedure SWP-ASU-01, Evaluations of Programs, Processes,
and Suppliers, Revision 17 which provided instructions for conducting internal and
external audits to determine the effectiveness of the Columbia Generating Station Quality
Assurance Program. Attachment 7.1 listed the audit frequency of the ISFSI program as
discretionary. The inspector noted that 10 CFR 72.176 required in part that the licensee
shall carry out a comprehensive system of planned and periodic audits to verify
compliance with all aspects of the quality assurance program. The licensee had been
conducting audits on a biennial frequency which met the requirement of 10 CFR 72.176,
however Procedure SWP-ASU-01 did not specify the appropriate regulatory requirement
for conducting a periodic audit of the ISFSI programs. The licensee initiated
CR 00180254 to evaluate the discrepancy.
1.3
Conclusions
Two hydrogen burn events occurred during welding of the MPC lid-to-shell welds on
canister serial numbers 168 and 169. During the welding operations for canister serial
number 168 the licensee had elected to suspend combustible gas monitoring after the
completion of the root pass weld. Although the licensee subsequently implemented
Enclosure 1
- 10 -
procedure changes to require combustible gas monitoring during the entire MPC lid-to-
shell weld process, the combustible gas monitoring configuration was ineffective in
determining the presence of combustible gases and a second hydrogen burn event
occurred during welding operations on MPC canister serial number 169. Following the
second hydrogen burn event, the licensee placed the MPC in a safe configuration and
brought in individuals with outside industry experience to determine the causes of the
hydrogen burn events and determine corrective actions to prevent recurrence. The
licensee implemented changes to introduce an inert gas (argon) beneath the MPC lid
during the lid-to-shell welding process and to relocate the explosive gas monitor sampling
point to the vicinity of the MPC vent port. The completion of the MPC lid-to-shell weld on
canister serial number 169 and the welding of the MPC lid-to-shell weld on canister serial
number 170 occurred without further incident. A Notice of Violation is being issued,
consistent with Section VI.A.1 of the NRC Enforcement Policy for failure to monitor
combustible gas concentrations during the MPC lid-to-shell weld.
The licensee procedures contained sufficient information to select and load spent fuel
assemblies into storage in compliance with CoC, Appendix B requirements. Selected fuel
assemblies were verified by the inspector to meet the CoC, Appendix B requirements.
The licensee was performing radiological surveys of canister contamination and cask
dose rates in accordance with the Technical Specification requirements. Results of
surveys performed for selected canisters and casks were well below the Technical
Specification limits.
The licensee was meeting the temperature monitoring requirements of Technical
Specification 3.1.2.1 by performing daily temperature readings of the cask outlet vents
and ambient air. All of the selected daily temperature readings reviewed were found to be
below the Technical Specification and licensee specified maximum temperature limits.
The ISFSI related condition reports sampled from the licensees corrective action system
adequately address the identified deficiencies and provide appropriate corrective actions.
The licensee was meeting the requirements of 10 CFR 72.176 for conducting periodic
audits of the ISFSI program. Deficiencies discovered during the audits were entered into
the licensee corrective action program for evaluation, as appropriate.
2
10 CFR 72.48 Evaluations (60857)
2.1
Inspection Scope
The licensees 10 CFR 72.48 program and selected 10 CFR 72.48
evaluations/screenings were reviewed to determine compliance with regulatory
requirements.
2.2
Observations and Findings
Procedure SWP-LIC-02, Licensing Basis Impact Determinations, Revision 7, provided
the overall guidance for the licensee process for meeting the requirements of
10 CFR 72.48. Section 4.3.2 instructed the preparer of the change document to perform
an applicability determination to decide which change processes apply to the proposed
Enclosure 1
- 11 -
activity, including a 10 CFR 72.48 screen or evaluation. Section 4.4.1 of Procedure SWP-
LIC-02 instructed the preparer to perform a 10 CFR 72.48 screen when directed by the
licensees applicability determination or the guidance contained in NEI 96-07, Appendix B.
Thus, Procedure SWP-LIC-02 instructed the preparer to use guidance from Procedure
SWP-LIC-02 and NEI 96-07, Appendix B when performing 10 CFR 72.48 reviews.
The licensee provided a list of the 10 CFR 72.48 screenings and single evaluation that
had been performed since the last NRC inspection conducted in March 2004. The
inspector selected 10 CFR 72.48 screen numbers 7248-04-0012, 7248-06-002 and 7248-
07-0001 along with 10 CFR 72.48 evaluation number 7248-07-002 for review. No issues
or concerns were identified with the selected 10 CFR 72.48 regulatory reviews.
During the 10 CFR 72.48 regulatory review, the inspector noted that there were no 10
CFR 72.48 screenings or evaluations that had been performed by the licensee specifically
associated with revision four or five to the Energy Northwest Independent Spent Fuel
Storage Installation 10 CFR 72.212 Evaluation.
Regulation 10 CFR 72.212(b)(2)(ii) required in part that the licensee shall evaluate any
changes to the written evaluations required by 10 CFR 72.212 using the requirements of
10 CFR 72.48(c). The 10 CFR 72.212(b) report incorporated several written evaluations
that provide documentation of how the general licensee is meeting the regulatory
requirements. The written evaluations required by 10 CFR 72.212(b)(2)(i)(A) include
showing that the conditions set forth in the CoC have been met. Holtec CoC Condition 2
required that written operating procedures for cask handling, loading, movement,
surveillance, and maintenance are consistent with the technical basis described in
Chapter 8 of the Final Safety Analysis Report (FSAR). In accordance with the
requirements of 10 CFR 72.212(b)(2)(i)(A), Energy Northwest provided a written
evaluation of how Columbia Generating Station operating procedures were meeting the
requirements of CoC Condition 2 in Section 1.1.2 of the Energy Northwest Independent
Spent Fuel Storage Installation 10 CFR 72.212 Evaluation.
As previously noted, Procedure SWP-LIC-02 directed the user to use NEI 96-07
Appendix B for guidance in determining when to perform a 10 CFR 72.48 screen.
Section B4.1.7 of NEI 96-07, Appendix B states that when a CoC holder has
screened/evaluated a cask design change under 10 CFR 72.48 and determined that prior
NRC approval is not required, a general licensee wanting to adopt the change would not
be required to do a separate screening/evaluation for the change if the site-specific
10 CFR 72.212 evaluations are not changed. However, the general licensee should
review their site-specific 10 CFR 72.212 evaluations to determine if any information would
be changed by the cask design change and, if so, perform a 10 CFR 72.48
screening/evaluation as required by 10 CFR 72.212(b)(2)(ii). The answers and/or
justification used in the 10 CFR 72.48 screening/evaluation may be taken from the CoC
holders 10 CFR 72.48 screening/evaluation if they could also apply to the general
licensee screening/evaluation.
Revision 5 of the Energy Northwest Independent Spent Fuel Storage Installation
10 CFR 72.212 Evaluation, incorporated a Holtec Supplier Manufacturing Deficiency
Report (SMDR) that reduced the number of HI-TRAC top lid bolts that were required to be
installed. This change was added to the written evaluation contained in Section 1.1.2,
Enclosure 1
- 12 -
Operating Procedures, of the Energy Northwest Independent Spent Fuel Storage
Installation 10 CFR 72.212 Evaluation. The cask vendor provided the 10 CFR 72.48
Evaluation Number 876 to Energy Northwest, which determined that prior NRC approval
was not required to implement the change. Energy Northwest utilized the Holtec SMDR
and associated 10 CFR 72.48 Evaluation as the justification for the change to Revision 5
of the Energy Northwest Independent Spent Fuel Storage Installation 10 CFR 72.212
Evaluation. A separate 10 CFR 72.48 screen or evaluation was not performed by the
licensee when incorporating the changes to the written evaluations in the Energy
Northwest Independent Spent Fuel Storage Installation 10 CFR 72.212 Evaluation. The
cask vendor 10 CFR 72.48 Evaluation Number 876 was reviewed by the inspector and
determined to adequately address the proposed change per the requirements of 10 CFR
72.48(c).
As previously stated, Regulation 10 CFR 72.212(b)(2)(ii) required in part that the licensee
shall evaluate any changes to the written evaluations required by 10 CFR 72.212 using
the requirements of 10 CFR 72.48(c). Contrary to this requirement, Energy Northwest
revised the written evaluation contained in Section 1.1.2 of the Energy Northwest
Independent Spent Fuel Storage Installation 10 CFR 72.212 Evaluation, Revision 5
without performing a 10 CFR 72.48 screen/evaluation. This is a violation of 10 CFR
72.212(b)(2)(ii). This Severity Level IV violation is being treated as a Non-Cited Violation,
consistent with Section VI.A.1 of the NRC Enforcement Policy. This violation is in the
licensees corrective action program as CR 181046.
Revision 4 of the Energy Northwest Independent Spent Fuel Storage Installation
10 CFR 72.212 Evaluation, incorporated over 40 separate changes. The licensee
incorporated administrative and editorial changes as well as changes associated with
Amendment 2 of Holtec CoC 1014. These changes were incorporated without a licensee
10 CFR 72.48 screening or evaluation associated with the 10 CFR 72.212 revision.
There were also several changes which were incorporated into written evaluations
contained in the Energy Northwest Independent Spent Fuel Storage Installation 10 CFR
72.212 Evaluation, that used a separate 10 CFR 72.48 screen/evaluation to evaluate
each proposed change. Finally, Appendix A and B were added to the Energy Northwest
Independent Spent Fuel Storage Installation 10 CFR 72.212 Evaluation, which included a
table that referenced the MPC serial numbers and the applicable Supplier Manufacturer
Deviation Reports (SMDRs) that had been issued against the MPC from the cask vendor.
After a thorough review of all the changes that had been made to Revision 4 of the
Energy Northwest Independent Spent Fuel Storage Installation 10 CFR 72.212
Evaluation, the staff determined that there were no negative findings associated with
Revision 4.
2.3
Conclusions
The licensee 10 CFR 72.48 screenings and the single 10 CFR 72.48 evaluation had been
performed in accordance with the requirements of 10 CFR 72.48(c). However, the
licensee did not perform a 10 CFR 72.48(c) review of the changes to the written
evaluations contained in Section 1.1.2 of the Energy Northwest Independent Spent Fuel
Enclosure 1
- 13 -
Storage Installation 10 CFR 72.212 Evaluation, as required by 10 CFR 72.212(b)(2)(ii).
This violation is being treated as a Non-Cited Violation, consistent with Section VI.A.1 of
3
Follow-up (IP 92701)
(Closed) IFI 72-35/0401-01 Review of the 10 CFR 72.212(b) Changes Needed to Support
the Hydrogen Water Chemistry Project. On April 23, 2004, the NRC issued Inspection
Report 50-397/04-07; 72-035/04-01 which included Inspection Follow-up Item (IFI) 72-
35/0201-01. The licensee had performed a 10 CFR 72.48 screening (Screen 03-010) that
had determined the storage of the hydrogen onsite and the location of the underground
hydrogen pipeline was bounded by previously analyzed accidents. The inspectors issued
IFI to review the changes made to the licensees 10 CFR 72.212 report after the hydrogen
water chemistry project had been incorporated.
The inspector reviewed the Energy Northwest Licensing Document Change Notice Form
Number LDCN 72212-03-066, and the Energy Northwest Independent Spent Fuel
Storage Installation 10 CFR 72.212 Evaluation, Revision 2, which incorporated relevant
changes associated with the hydrogen water chemistry project. The licensee had
performed a site-specific fire and explosion hazards analysis in Section 1.3.3.4, Item 5,
Fires and Explosions and < 50 Gallons of Combustible Fuel in Transporter Fuel Tank.
The analysis indicated that the existing explosion hazards analysis, which considered the
probability of a projectile impacting the HI-STORM cask during transportation or storage,
was not altered by the inclusion of the hydrogen water chemistry project. The licensee
concluded that results for the conservative calculations for all scenarios, including any
explosions associated with the hydrogen water chemistry project, continue to show that all
probabilities of a projectile impacting a HI-STORM cask are less than 10-6.
The use of a risk informed approach to determine the acceptability of the site-specific fire
and explosion hazards analysis was discussed with inspectors from the Spent Fuel
Storage and Transportation (SFST) Office. SFST determined that this was an acceptable
technique for the site-specific fire and explosion hazards analysis, as there has been no
specific regulatory restrictions placed on the methods that the general licensees could use
for this analysis and that the risk associated with an event having a frequency less than
one in 10-6 has been acknowledged by the agency as being acceptably low.
4
Exit Meeting Summary
A debrief was held with members of the licensee management at the conclusion of the
initial onsite inspection on April 17, 2008. At the conclusion of the inspection a telephonic
exit was held with members of the licensee management on May 19, 2008. The licensee
did not identify as proprietary any information provided to, or reviewed by, the inspectors.
Attachment 1
A1-1
ATTACHMENT 1
SUPPLEMENTAL IFORMATION
PARTIAL LIST OF PERSON CONTACTED
Licensee Personnel
M. Davis, Radiological Support Supervisor
R. Fuller, ISFSI Project Manager
R. Garcia, Licensing Engineer
D. Gregoire, Licensing Engineer
M. Humphries, Licensing Supervisor
C. Madden, Scientist
S. Nappi, Quality Audit
S. Rejniak, Principal Engineer
J. Suing, Reactor Maintenance Manager
Contract Personnel
C. Deady, Welder Foreman
D. Larken, ISFSI Project Manager
K. Saunders, Welder
M. Wright, Welder
INSPECTION PROCEDURES USED
60855.1
Operation of an ISFSI at Operating Plants
60857
Review of 10 CFR 72.48 Evaluations
92701
Follow-Up
ITEMS OPENED, CLOSED, AND DISCUSSED
Opened
72-35/0801-01 NOV
Failure to monitor the combustible gas concentration while performing the
72-35/0801-02 NCV
Failure to perform 10 CFR 72.48(c) review when revising the 10 CFR
72.212(b) written evaluations
Closed
72-35/0401-01 IFI
Review of the 10 CFR 72.212(b) Changes Needed to Support the
Hydrogen Water Chemistry Project
72-35/0801-02 NCV
Failure to perform 10 CFR 72.48(c) review when revising the 10 CFR
72.212(b) written evaluations
Attachment 1
A1-2
Discussed
None
LIST OF ACRONYMS
CFR
Code of Federal Regulations
Columbia Generating Station
Certificate of Compliance
CR
Condition Report
Final Safety Analysis Report
IFI
Inspection Follow-up Item
Independent Spent Fuel Storage Installation
Multi-Purpose Canister
NEI
Nuclear Energy Institute
NRC
Nuclear Regulatory Commission
PER
Problem Evaluation Request
Spent Fuel Storage and Transportation
Supplier Manufacturing Deficiency Report
Attachment 2
A2-1
ATTACHMENT 2
LOADED HI-STORM 100S CASKS AT THE COLUMBIA GENERATING STATIONS ISFSI
LOADING
ORDER
MPC (canister)
SERIAL #
DATE
ON PAD
HEAT LOAD
(Kw)
BURNUP
MWd/MTU
MAXIMUM FUEL
ENRICHMENT %
PERSON-REM
DOSE
1
MPC-68-028
09/22/02
10.81
32,299
2.72
0.385
2
MPC-68-031
10/07/02
11.10
32,416
2.72
0.341
3
MPC-68-022
10/28/02
11.30
32,541
2.72
0.315
4
MPC-68-039
11/18/02
11.42
33,045
2.72
0.298
5
MPC-68-033
12/09/02
11.20
32,804
2.72
0.245
6
MPC-68-091
02/25/04
12.00
32,318
2.72
0.390
7
MPC-68-092
03/03/04
17.10
38,607
2.92
0.298
8
MPC-68-093
03/11/04
17.10
38,738
2.92
0.320
9
MPC-68-094
03/18/04
17.00
38,732
2.92
0.304
10
MPC-68-095
03/24/04
17.00
38,772
2.92
0.276
11
MPC-68-096
03/31/04
17.10
38,729
2.92
0.253
12
MPC-68-097
04/06/04
17.20
39,121
2.92
0.251
13
MPC-68-098
04/14/04
17.10
39,002
2.92
0.237
14
MPC-68-099
04/20/04
17.00
39,008
2.92
0.208
15
MPC-68-100
04/25/04
16.80
38,982
2.92
0.199
16
MPC-68-162
02/22/08
11.91
39,172
3.22
0.260
17
MPC-68-163
02/29/08
21.00
43,302
3.56
0.458
18
MPC-68-164
03/07/08
21.02
43,181
3.56
0.426
19
MPC-68-165
03/14/08
21.02
43,010
3.56
0.343
20
MPC-68-166
03/21/08
21.00
43,330
3.56
0.379
21
MPC-68-167
04/04/08
21.03
42,827
3.56
0.587
22
MPC-68-168
04/11/08
21.01
43,020
3.56
0.503
23
MPC-68-169
04/29/08
20.88
42,269
3.87
0.362
Notes:
1) Heat Load (Kw) is the sum of the heat load values for all spent fuel assemblies in the cask
2) Burnup is the value for the spent fuel assembly with the highest individual discharge burnup
3) Fuel Enrichment is the spent fuel assembly with the highest individual enrichment percent of U-235