ML13140A430
| ML13140A430 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 05/20/2013 |
| From: | Spitzberg D NRC/RGN-IV/DNMS/RSFSB |
| To: | Halpin E Pacific Gas & Electric Co |
| Lee Brookhart | |
| References | |
| EA-13-090 IR-13-001, IR-13-008 | |
| Download: ML13140A430 (32) | |
See also: IR 05000275/2013008
Text
N U C LE AR R E GU LA TOR Y C OM MI S SI ON
R E G IO N I V
1600 EAST LAMAR BLVD
AR L I NG TO N , TE X AS 7 60 1 1 - 4511
May 20, 2013
Mr. Edward D. Halpin
Senior Vice President and
Chief Nuclear Officer
Pacific Gas and Electric Company
Diablo Canyon Power Plant
P.O. Box 56, Mail Code 104/6
Avila Beach, CA 93424
SUBJECT: DIABLO CANYON POWER PLANT INDEPENDENT SPENT FUEL STORAGE
INSTALLATION (ISFSI) INSPECTION REPORT 05000275/2013008,
05000323/2013008, 07200026/2013001, AND NOTICE OF VIOLATION
Dear Mr. Halpin:
This letter refers to a routine inspection conducted on April 2 - 4, 2013, of your dry cask storage
activities associated with your Independent Spent Fuel Storage Installation (ISFSI). The
inspection was conducted to confirm compliance with the requirements specified in the Technical
Specifications associated with Materials License No. SNM-2511, the Diablo Canyon ISFSI Final
Safety Analysis Report (FSAR), and Title 10 of the Code of Federal Regulations (CFR) Part 20
and Part 72. Within these areas, the inspection included a review of radiation safety, cask
thermal monitoring, quality assurance, corrective action program, safety evaluations, cask
maintenance, and how you addressed industry issues that affected your ISFSI program. Also
reviewed, were changes made to your ISFSI program since the last ISFSI inspection conducted
by the U.S. Nuclear Regulatory Commission (NRC). An exit was conducted with your staff to
discuss the findings of the inspection on April 4, 2013. However, during the in-office review, a
violation of NRC regulations was identified. On April 30, 2013, a final exit was conducted by
telephone, with members of your management and staff.
Based on the results of this inspection, the NRC has determined that a Severity Level IV
violation of NRC requirements occurred. The violation involved an inadequate safety review of
a procedure, as required by 10 CFR 72.48. The procedure contained steps that isolated the
canister while loaded with spent fuel and filled with water. The canister was isolated with no
release path or access to a pressure relief valve. This placed the canister in an unanalyzed
condition with the possibility of creating an accident condition not analyzed in the FSAR. This
violation was evaluated in accordance with the NRC Enforcement Policy. The current
Enforcement Policy is included on the NRCs Web site at http://www.nrc.gov/about- nrc/
regulatory/enforcement/enforce-pol.html.
E. Halpin -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. The violation is being
cited because Diablo Canyon (1) was notified of a potential non-compliance in its procedure by
the cask vendor (Holtec); (2) failed to restore compliance within a reasonable period of time;
(3) failed to place the issue in the corrective action program prior to the 2012 loading campaign;
and (4) proceeded to use the procedure, which subsequently placed seven canisters in an
unanalyzed condition from January 2012 through March 2012.
You are required to respond to this letter and should follow the instructions specified in the
enclosed Notice when preparing your response. If you have additional information that you
believe the NRC should consider, you may provide it in your response to the Notice. The NRC
review of your response to the Notice will also 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, its
enclosure, and your response, will be made available electronically for public inspection in the
NRC Public Document Room or from the NRC's Agency-wide Document Access Management
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 or proprietary
information so that it can be made available to the public without redaction.
Should you have any questions concerning this inspection, please contact me at 817-200-1191
or Mr. Lee Brookhart at 817-200-1549.
Sincerely,
/RA by Jack E. Whitten Acting for/
D. Blair Spitzberg, Ph.D. Chief
Repository & Spent Fuel Safety Branch
Division of Nuclear Materials Safety
Dockets: 50-275, 50-323, 72-26
Licenses: DPR-80, DPR-82, SNM-2511
Enclosures:
1. Notice of Violation
2. Inspection Reports 05000275/2013008,
05000323/2013008, and 07200026/2013001
w/attachments:
1. Supplemental Information
2. Loaded Casks at Diablo Canyon Power Plant ISFSI
cc w/encls: Listserv
E. Halpin -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. The violation is being
cited because Diablo Canyon (1) was notified of a potential non-compliance in its procedure by
the cask vendor (Holtec); (2) failed to restore compliance within a reasonable period of time;
(3) failed to place the issue in the corrective action program prior to the 2012 loading campaign;
and (4) proceeded to use the procedure, which subsequently placed seven canisters in an
unanalyzed condition from January 2012 through March 2012.
You are required to respond to this letter and should follow the instructions specified in the
enclosed Notice when preparing your response. If you have additional information that you
believe the NRC should consider, you may provide it in your response to the Notice. The NRC
review of your response to the Notice will also 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, its
enclosure, and your response, will be made available electronically for public inspection in the
NRC Public Document Room or from the NRC's Agency-wide Document Access Management
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 or proprietary
information so that it can be made available to the public without redaction.
Should you have any questions concerning this inspection, please contact me at 817-200-1191
or Mr. Lee Brookhart at 817-200-1549.
Sincerely,
/RA by Jack E. Whitten Acting for/
D. Blair Spitzberg, Ph.D. Chief
Repository & Spent Fuel Safety Branch
Division of Nuclear Materials Safety
Dockets: 50-275, 50-323, 72-26
Licenses: DPR-80, DPR-82, SNM-2511
Enclosures:
1. Notice of Violation
2. Inspection Reports 05000275/2013008,
05000323/2013008, and 07200026/2013001
w/attachments:
1. Supplemental Information
2. Loaded Casks at Diablo Canyon Power Plant ISFSI
cc w/encls: ListServ
DISTRIBUTION w/encls:
See next page
FINAL: R:\_REACTORS\__DC\2013\DC2013008-ISFSI-LEB
ADAMS: No X Yes X SUNSI Review Complete Reviewer Initials: LEB
X Publicly Available X Non-Sensitive
Non-publicly Available Sensitive
KEYWORD:
RIV:DNMS/RSFS RIV:DNMS/RSFS RIV:OE R-IV/C:RSFS
LEBrookhart: jm * EJSimpson RSBrowder DBSpitzberg
/By email/ /RA D.Blair Spitzberg for/ /RA/ /RA by JEWhitten for/
05/09/2013 05/17/2013 05/16/2013 05/20/2013
OFFICIAL RECORD COPY T=Telephone E=E-mail F=Fax
Letter to Edward Halpin from D. Blair Spitzberg, dated May 20, 2013.
SUBJECT: DIABLO CANYON POWER PLANT INDEPENDENT SPENT FUEL STORAGE
INSTALLATION (ISFSI) INSPECTION REPORT 05000275/2013008,
05000323/2013008, 07200026/2013001, AND NOTICE OF VIOLATION
DISTRIBUTION w/attachments:
Regional Administrator (Art.Howell@nrc.gov)
Acting Deputy Regional Administrator (Robert.Lewis@nrc.gov)
DRP Director (Kriss.Kennedy@nrc.gov)
DRP Deputy Director, Acting (Michael.Scott@nrc.gov)
DRS Director (Tom.Blount@nrc.gov)
DRS Deputy Director, Acting (Jeff.Clark@nrc.gov)
Senior Resident Inspector (Thomas.Hipschman@nrc.gov)
Resident Inspector (Laura.Micewski@nrc.gov)
DC Administrative Assistant (Madeleine.Arel-Davis@nrc.gov)
Branch Chief, DRP/B (Neil.Okeefe@nrc.gov)
Senior Project Engineer, DRP/B (Michael.Bloodgood@nrc.gov)
Project Engineer, DRP/B (David.You@nrc.gov)
DNMS Director (Anton.Vegel@nrc.gov)
DNMS Deputy Director (Vivian.Campbell@nrc.gov)
RSFS Branch Chief (Blair.Spitzberg@nrc.gov)
RSFS Inspector (Lee.Brookhart@nrc.gov)
RSFS Inspector (Eric.Simpson@nrc.gov)
Project Manager (Joseph.Sebrosky@nrc.gov)
Project Manager, SFST (William.Allen@nrc.gov)
Public Affairs Officer (Victor.Dricks@nrc.gov)
Public Affairs Officer (Lara.Uselding@nrc.gov)
RITS Coordinator (Marisa.Herrera@nrc.gov)
TSB Technical Assistant (Loretta.Williams@nrc.gov)
RIV Office of Enforcement ACES (Rachel.Browder@nrc.gov)
RIV Office of Enforcement ACES (Christi.Maier@nrc.gov)
RIV Office of Enforcement ACES (Heather.Gepford@nrc.gov)
SFST Branch Chief (Eric.Benner@nrc.gov)
Regional Counsel (Karla.Fuller@nrc.gov)
Congressional Affairs Officer (Jenny.Weil@nrc.gov)
RIV/ETA: OEDO (Doug.Huyck@nrc.gov)
OEMail_Resources@nrc.gov
ROPreports
NOTICE OF VIOLATION
Pacific Gas and Electric Company Docket Nos. 50-275, 50-323, 72-26
Diablo Canyon Power Plant License Nos. DPR-80, DPR-82, SNM-2511
During a routine Independent Spent Fuel Storage Installation (ISFSI) inspection conducted on
April 2 - 4, 2013, a violation of the U.S. Nuclear Regulatory Commission (NRC) requirements
was identified. In accordance with the NRC Enforcement Policy, the violation is listed below:
10 CFR 72.48(c)(1)(i)(C), requires, in part that a licensee or certificate holder may make
changes in the facility or spent fuel storage cask design as described in the Final Safety
Analysis Report (FSAR)(as updated), make changes in the procedures as described in
the FSAR (as update) without obtaining a license amendment pursuant to 10 CFR 72.56,
if the change does not meet any of the criteria in paragraph (c)(2) of this section.
10 CFR 72.48(c)(2)(v) requires, in part, that a specific licensee shall obtain a license
amendment pursuant to 10 CFR 72.56, prior to implementing a proposed change, if the
change would create a possibility for an accident of a different type than any previously
evaluated in the FSAR (as updated).
Contrary to the above, from late January 2012 through March 2012, the licensee failed to
obtain a license amendment pursuant to 10 CFR 72.56, prior to implementing a proposed
change that would create a possibility for an accident of a different type than previously
evaluated in the FSAR (as updated). Specifically, the licensee made changes to
Procedure HPP-1073-300, Procedure for Drying, Backfill, and Sealing the MPC at
DCPP, Revision 9, which allowed the licensee to take steps that were not consistent with
Chapter 5 of the FSAR and resulted in the isolation of the canister, while filled with water,
which created the possibility of an accident not evaluated in the FSAR. Diablo Canyon
used this procedure and implemented the steps which resulted in an unanalyzed
condition, during the loading of seven casks from January 2012 through March 2012.
This is a Severity Level IV violation (Section 6.1.d.2).
Pursuant to the provisions of 10 CFR 2.201, Pacific Gas and Electric Company 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, (c/o Blair Spitzberg, Ph.D., Chief, Repository Spent Fuel
Safety Branch, DNMS) and a copy to the NRC Resident Inspector at Diablo Canyon Power
Plant, 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-13-090" 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; 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 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.
Enclosure 1
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 Agency-wide Document Access Management
System (ADAMS), accessible from the NRC Web site at http://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.
Dated this 20th day of May 2013.
-2-
U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Dockets: 05000275, 05000323, 07200026
Licenses: DPR-80, DPR-82, SNM-2511
Report Nos.: 05000275/2013008, 05000323/2013008, and 07200026/2013001
Licensee: Pacific Gas and Electric Company (PG&E)
Facility: Diablo Canyon Power Plant Units 1, 2, and
Independent Spent Fuel Storage Installation (ISFSI)
Location: 7.5 miles NW of Avila Beach
Avila Beach, CA
Dates: April 2 - 4, 2013
Inspector: Lee Brookhart, Inspector, RIV RSFS
Accompanying
Personnel: Eric Simpson, Inspector-in-Training, RIV RSFS
Approved By: D. Blair Spitzberg, Ph.D., Chief
Repository & Spent Fuel Safety Branch
Division of Nuclear Materials Safety
Enclosure 2
EXECUTIVE SUMMARY
Diablo Canyon Power Plant
NRC Inspection Report 05000275/2013008, 05000323/2013008, and 07200026/2013001
The U.S. Nuclear Regulatory Commission (NRC) conducted a routine inspection of the
licensees programs and activities for safe handling and storage of spent fuel at the Diablo
Canyon Independent Spent Fuel Storage Installation (ISFSI) on April 2 through April 4, 2013.
The inspection reviewed a number of topics to evaluate compliance with the applicable NRC
regulations and the provisions of its site specific license SMN-2511 which utilizes the Holtec
HI-STORM 100 design. At the time of the inspection, 23 HI-STORM 100 Short Anchored (SA)
casks were loaded and stored on the Diablo Canyon ISFSI pad. The casks were being
maintained in good physical condition. Radiological dose rates around the ISFSI were low. A
review of the environmental monitoring program demonstrated that radiological exposures to
offsite locations were not occurring from the storage of the spent fuel at the ISFSI. Personnel
exposures during cask loading were improving as Diablo Canyon continued its loading
campaigns. The third and latest loading campaign doses were low and were comparable to
doses typically seen during loading campaigns at the other Region IV sites. The quality
assurance program and corrective action program were being effectively implemented to
capture and correct issues related to the dry cask storage program.
The inspection reviewed documentation relevant to ISFSI activities and operations that have
occurred at Diablo Canyon since the last ISFSI inspection that was performed in June of 2009,
which observed the loading of Diablo Canyons first cask. The documentation review included
quality assurance, radiological conditions, corrective actions, compliance to technical
specifications, compliance to Updated Final Safety Analysis Report (FSAR) requirements, and
industry ISFSI issues that affected the site.
Operation of an ISFSI at Operating Plants (60855.1)
The licensee was conducting quality assurance audits of the ISFSI program. A review of
four audit reports determined that the audits were covering a broad range of topics. A
number of issues were identified in the audits and entered into the corrective action
program for resolution. (Section 1.2.a)
Radiation levels around the ISFSI pad were within expected ranges for a site with
23 casks in storage. For the environmental monitoring periods of 2009, 2010, and 2011,
the dose from the ISFSI had no effect on dosimetry located between the ISFSI and the
site boundary. (Section 1.2.b)
Documents and records related to the 2009, 2010, and 2012 ISFSI cask loading
campaigns were reviewed. Information included personnel dosimetry records, total
personnel dose received per cask loading, and neutron doses received by workers
during cask loading activities. Worker doses to load a cask have continued to decrease
from previous loadings, with the last campaign averaging 0.121 person-rem/cask.
(Section 1.2.c)
Diablo Canyon was recording measurable neutron dose that ISFSI workers received
during the loading campaigns through the use of the Panasonic UD-813 dosimeter. The
Panasonic UD-813 dosimeters used for measuring personnel dose of legal record were
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noted to have recorded doses which were statistically close to the data from the
electronic alarming dosimeters worn by the workers for both gamma and neutron dose.
(Section 1.2.d)
Required records were maintained that described the specific fuel parameters for the
spent fuel stored in each of the licensees loaded casks. (Section 1.2.e)
Since the last NRC ISFSI inspection Diablo Canyon has requested and NRC approved
two license amendment changes and had revised the ISFSI FSAR twice in Revision 3
and Revision 4. No issues were identified in review of these changes. (Section 1.2.f)
The FSAR does not include an accident analysis for a situation where the canister is filled
with water after the lid is welded in place, with the vent and drain port caps closed, which
resulted in an isolated condition. The licensee failed to perform an adequate safety review
per 10 CFR 72.48 to ensure the Procedure HPP-1073-300 followed the process as
outlined in Chapter 5 of the FSAR. Federal regulations in 10 CFR 72.48(c)(1) states, in
part, that a licensee may make changes to procedures as described in the FSAR, if the
change does not create a possibility for an accident of a different type than any previously
evaluated in the FSAR. Contrary to this, the licensee failed to follow procedures as
described in the FSAR and created a possibility for an accident not previously evaluated in
the FSAR. This was determined by the NRC to be a Severity Level IV violation. The
violation was cited in the Notice of Violation because Diablo Canyon was notified of a
potential non-compliance in its procedure by the cask vendor (Holtec) and failed to restore
compliance within a reasonable period of time, failed to place the issue in the corrective
action program prior to the 2012 campaign, and proceeded to use the procedure that
placed seven canisters in an unanalyzed condition from January 2012 through March
2012. (Section 1.2.g)
Technical Specification 3.1.2 vent inspection requirements for the HI-STORMs were
performed daily as required. (Section 1.2.h)
Selected condition reports were reviewed for the period June 2009 through April 2013. A
wide range of issues had been identified and resolved. Resolutions of the issues were
appropriate for the safety significance of the issue. No adverse trends were identified
during the review. (Section 1.2.i)
Annual cask inspections had been completed in accordance with FSAR requirements.
Only minor deficiencies were identified and placed in the corrective action program for
resolution. (Section 1.2.j)
Westinghouse identified an issue with CaskWorks, a program utilized by Diablo Canyon
for analysis of its fuel assemblies characteristics. The issue was placed in the
corrective action program and appropriately resolved. (Section 1.2.k)
Diablo Canyons response to NRC Information Notice 2012-20 has been adequately
captured and documented in the corrective action program. (Section 1.2.l)
Diablo Canyon submitted its ISFSI Decommissioning Funding Plan in compliance with
10 CFR 72.30(b) on the submittal deadline of December 17, 2012. (Section 1.2.m)
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Review of 10 CFR 72.48 Evaluations (60857)
All required safety screenings and safety evaluations had been performed in accordance
with procedures and 10 CFR 72.48 requirements except for the issue discussed in
Section 1.2.g of this report. All other screenings and safety evaluations reviewed were
determined to be adequately evaluated. (Section 2)
Followup (92701)
Licensee Event Report Notification 47580, dated January 9, 2012 related to loose anchor
stud nuts that were found on three loaded HI-STORMs. The licensee adequately addressed
the condition and implemented appropriate corrective actions to prevent reoccurrence.
(Section 3)
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Report Details
Summary of Facility Status
Twenty three HI-STORM 100 Short Anchored (SA) storage casks each containing a 32 assembly
Multi-Purpose Canister (MPC), were currently in storage at the Diablo Canyon ISFSI. Each
MPC-32 canister holds 32 pressurized water reactor (PWR) spent fuel assemblies. The casks were
being monitored in compliance with the thermal monitoring requirements of Technical Specification 3.1.2 and for radiation levels in compliance with 10 CFR Part 20 and 10 CFR Part 72 requirements.
The casks were located inside a separate protected area outside the plants 10 CFR Part 50
protected area. Diablo Canyon had loaded twenty two casks since the last NRC routine ISFSI
inspection was performed in June 2009. A tour of the ISFSI area found the casks to be in good
physical condition. Dosimeters located around the casks were providing radiological dose data
within the expected levels for an ISFSI with 23 casks in storage. The ISFSI currently consists of
two large concrete storage pads that can hold 20 anchored casks each. The ISFSI protected area
was designed to hold a total of seven pads, each holding 20 anchored casks. Diablo Canyon plans
to construct the remaining five pads in 2014. This would allow for a total capacity of 138 anchored
casks with two slots left empty for shuffling purposes. The ISFSI casks were loaded using various
SNM-2511 license amendments and FSAR revisions (see Attachment 2) but were all currently
maintained under SNM-2511 License Amendment 2 and the FSAR, Revision 4.
The two reactors at Diablo Canyon are Westinghouse pressurized water reactors. A full core for
each Westinghouse reactor consisted of 193 fuel assemblies. Refueling outages were
performed approximately every 20 months for each reactor. Each refueling outage replaces
approximately 88 assemblies in the core with new assemblies. A separate spent fuel pool was
available for each reactor with sufficient room currently available for full core offload. The
following table provides the current summary of the number of assemblies in the spent fuel
pools and the available space.
Unit 1 Unit 2
Spent Fuel Pool assembly capacity 1312 1309
Empty usable locations in the spent fuel pool 252 253
Diablo Canyon plans to load approximately six casks every two years starting in August 2013.
The removing of 96 assemblies (3 casks) from each pool will more than offset the 88 new
assemblies being added to the pools every 20 months due to a refueling outage. The cask with
the highest heat load to-date held 20.29 kW.
1 Operations of an Independent Spent Fuel Storage Installation (ISFSI) at Operating
Plants (60855.1)
1.1 Inspection Scope
An inspection of the status of the loaded casks at Diablo Canyon was completed to
verify compliance with requirements of its SNM-2511 License, ISFSI FSAR, and federal
regulations. The inspection reviewed a broad range of topics including audits and
surveillances conducted by the licensee, condition reports related to the ISFSI and the
fuel handling building crane, environmental radiological data collected around the ISFSI
for the past several years, compliance with Technical Specification 3.1.2 for ventilation
monitoring of the casks, review of the annual cask maintenance records, and review of
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industry issues that affected the sites ISFSI program. A tour of the ISFSI area was
performed and the inspectors observed radiation protection personnel take radiological
dose rates measurements around the perimeter of the ISFSI pad and near the casks.
1.2 Observations and Findings
a. Quality Assurance Audits and Surveillances
The Diablo Canyon Quality Verification Department had issued a number of audit reports
between 2009 and 2013. Many of the audit reports involved ISFSI program related
documentation, functions, and activities. Five audit reports were reviewed as part of the
inspection: Quality Verification Short Form Assessment #092320031 - Special Nuclear
Material Control, dated August 20, 2009; 2009 Technical Specification (TS) and Testing
Audit, dated October 23, 2009; 2010 Quality Assurance Program Audit, dated July 10,
2010; 2011 Technical Specification Audit, dated October 5, 2011; and 2011 Fuel
Management Program Audit, dated October 20, 2011.
The Short Form Assessment #092320031 identified fuel movement documentation
issues that had the potential to impact the ISFSIs record keeping program. The
problems identified were related to discrepancies in fuel bundle locations and fuel
movement documentation. The 2009 Technical Specification and Testing Audit found
minor errors and inaccuracies in Diablo Canyon ISFSI Technical Specification
procedures and documents. The 2010 Quality Assurance (QA) Program Audit found
some issues related to the Diablo Canyon ISFSI training program implementation. All
issues that were identified through the audits were placed in the corrective action
program and properly resolved.
In the 2011 Technical Specification Audit, the audit team assessed the applicability of an
industry-wide FSAR issue related to the potential for pressure to build-up in a water-filled
canister while isolated (for more discussion on this see Section 1.2.g).
The 2011 Fuel Management Audit covered areas such as QA records related to fuel
stored onsite in the dry cask storage system, ISFSI program and licensing requirements,
design control, operation, maintenance, and training. The audit team looked at the
ISFSI records and verified, by random sample, that they were readily retrievable from
the Records Management System and completed in accordance with plant standards.
The QA records were determined to be satisfactory. The audit documented that
combustible material was found stored inside the ISFSI fence, despite the outer ISFSI
fence being posted as a no combustible items storage area. This issue was entered
into the Diablo Canyon corrective action program under SAPN #50423487 and the
container was removed from inside the ISFSI fence.
b. Radiological Conditions Related to Stored Casks
A tour of the ISFSI pad was performed during the inspection. The tour found the
23 loaded HI-STORM casks to be in good condition. No flammable or combustible
materials were observed inside the ISFSI protected area. A recent radiological survey of
the ISFSI pad was provided to NRC inspectors prior to their arrival on-site. Two radiation
protection (RP) technicians accompanied the NRC inspectors during the pad tour. A
radiological survey was performed by the RP technician with a neutron sensitive remball
and an ion chamber for gamma radiation. A low-range gamma sensitive detector was
-6-
provided to the NRC inspectors. General area background readings before reaching the
ISFSI were zero mrem/hr neutron and 13 R/hr gamma. Survey measurements were
taken around the ISFSI pad, at selected cask lower vent locations, and at environmental
thermo luminescent (TLD) monitoring locations inside the ISFSI protected area fence. At
the time of the inspection ISFSI pad 1 located in the most eastern part of the ISFSI fenced
area contained 20 casks. ISFSI pad 2 contained three casks and pads 3-7 had not been
built. Pads 3-7 would lie to the west of pad 2, which contained three casks (see Figure 1).
The observed general exposure rates at the edge of the ISFSI pad 1 and 2 ranged from
135 to 1000 R/hr (0.135 to 1.0 mR/hr) gamma and less than 0.2 mrem/hr neutron.
Radiation levels measured at a few casks lower vent locations were 1.25 to 2.0 mR/hr
gamma and 1.6 to 2 mrem/hr neutron. The survey measurements confirmed the
measurements recorded on the survey that was provided earlier to NRC by the licensee.
There were four TLD
monitoring locations around
the ISFSI pad that were
responsible for measuring
the direct radiological impact
from the loaded casks (see
graphic inset on left). Those
monitoring locations were
identified by the Radiological
Environmental Monitoring
Program (REMP) as: IS-11,
a monitoring location to the
north of the pad, along the
centerline of pad 1 and pad
2, and at a distance of 51
feet north of the pad; IS-12, a
monitoring location centrally
located directly west of pad
2, at distance of 20 feet;
IS-13, a monitoring location
to the south of the pad, along
the centerline of pad 1 and
pad 2, and at a distance of
40 feet from the pad; and IS-
14, a monitoring location
centrally located directly east
of pad 1 and at a distance of
41 feet.
Figure 1 Diablo Canyon ISFSI Pad Orientation
The TLDs used at the four monitoring locations within the ISFSI fence were Panasonic
UD-813 dosimeters that monitor both gamma and neutron dose rates. Each of the four
monitoring locations included a TLD that was mounted on the outside of a monitoring
phantom. The phantom, a human tissue equivalent box, assisted the TLD in recording
both direct incident and back-scattered neutron dose. The phantom mimics the actual
dose response that a human would receive.
-7-
The gamma exposure rates measured during the NRC walk down at the monitoring
locations were: 110 µR/hr at IS-11; 60 µR/hr at IS-12; 173 µR/hr at IS-13; and 140 µR/hr
at IS-14. The measured dose rates at those locations were comparable to the annual
gamma TLD monitoring data provide in Table 1. The neutron percentage of the total
dose represented in the Table 1 by the % column, ranged from 9 to 17 percent
depending on the monitoring location.
Table 1, ISFSI Pad TLD Monitoring Annual Total Gamma & Neutron Dose in mrem
2010 2011 2012
Loc. Average
Neutron Total % Neutron Total % Neutron Total %
IS-11 39 446 9% 62 510 12% 99 650 15% 535
IS-12 53 588 9% 60 581 10% 131 776 17% 648
IS-13 132 1421 9% 149 1374 10% 156 1505 10% 1433
IS14 130 1231 11% 127 1111 11% 157 1195 13% 1179
Offsite and onsite monitoring data from the 2009, 2010, and 2011 Diablo Canyon Annual
Radiological Environmental Operating Reports (REOPs) were reviewed (Adams
Accession No. ML101260133, ML11129A085, ML11129A086, ML11129A087,
ML12128A479, ML1215A382, ML1215A383, ML12125A384, ML12125A386, and
ML1215A387). Those reports were generated by the Diablo Canyons Radiological
Environmental Monitoring Program (REMP) group. As part of the program, Diablo
Canyon placed eight environmental TLD monitoring locations just outside the ISFSI
fence to monitor the radiological impacts of the ISFSI. The TLDs used for those
locations were the Panasonic UD-814 model which measure only gamma doses.
Annual dose data for the eight TLDs located just outside the ISFSI fence, surrounding
the ISFSI are shown in Table 2. The TLDs outside the ISFSI fence started to record
higher annual doses after the licensee began loading casks in late 2009. The TLD
locations with higher readings were locations that were closer to ISFSI pads 1 and 2 that
held the loaded casks at the ISFSI.
Table 2, Annual Doses in mrem, outside the ISFSI Fence Monitoring Locations
TLD Identifier 2009 Total 2010 Total 2011 Total
IS-1 93.0 92.2 94.3
IS-2 94.6 96.6 99.6
IS-3 111.1 133.0 143.1
IS-4 166.3 286.5 305.1
IS-5 143.2 252.4 291.3
IS-6 126.0 186.6 214.2
IS-7 106.0 142.8 150.9
IS-8 83.1 83.1 87.1
Other TLDs of interested from the operating report included six TLDs that surrounded
the ISFSI at a distance of approximately 0.2 miles to 0.4 miles away. These TLDs lied in
between the ISFSI and Diablo Canyons property boundary. Those TLDs in Table 3,
remained statistically constant despite the cask loading campaigns that were perform
during 2009 through 2011.
-8-
Table 3, Annual Doses for Locations Between the ISFSI and the Site Boundary
TLD Identifier 2009 Total 2010 Total 2011 Total
2S1, West of the ISFSI 66.6 63.5 67.4
3S1, NW of the ISFSI 82.0 81.3 81.7
4S1, North of the ISFSI 80.5 80.5 80.5
5S3, NE of the ISFSI 76.4 74.2 75.4
6S1, East of the ISFSI 54.4 53.0 53.4
7S1, South of the ISFSI 74.4 73.7 79.4
For the monitoring periods of 2009, 2010, and 2011, the dose from the ISFSI had no
effect on dosimetry located between the ISFSI and the site boundary.
c. Radiological Information Related to Cask Loading
Documents and records related to the 2009, 2010, and 2012 cask loading campaigns
were provided by the radiation protection (RP) staff and reviewed. The dose received
during each casks loading was broken-down into functional activities of where the dose
was acquired. Those functional areas were: project management (PM), mechanical and
maintenance (M&M), radiation protection (RP), decontamination (DECON), operations
(OPS), and in-service Inspection (ISI) for the 2009 loading campaign (See Table 4,
below).
Table 4, 2009 ISFSI Loading Campaign Personnel Total Doses (neutron and
gamma) per ISFSI Program Area and Cask in mrem
MPC-30 MPC-12 MPC-10 MPC-14 MPC-17 MPC-21 MPC-65 MPC-8
PM 241 184 234 179 180 164 137 125
M&M 33 27 21 24 35 36 31 24
RP 69 44 39 25 22 22 15 9
DECON 15 13 15 11 10 11 11 9
OPS 11 6 7 6 6 6 2 2
ISI 1 0 0 0 0 0 0 0
Total 370 274 316 245 253 239 196 169
The doses during the first campaign tended to be highest for the program management,
mechanical and maintenance, and radiation protection areas. The radiological doses
tended to improved with each subsequent cask during the 2009 campaign.
During the 2010 and the 2012 loading campaigns at Diablo Canyon the RP program
added three additional groupings for dose tracking. Those activity areas included:
Holtec, an activity to track the doses of the Holtec crew that performed a majority of the
loading operations; PCI, an activity that that tracked doses to the welders and welding
non-destructive examination (NDE) specialists; and Bragg, an activity that tracked the
doses associated with a local crane rigging outfit that assisted during cask movements
while at the cask transfer facility near the ISFSI pad (see Table 5 and Table 6).
Table 5, 2010 ISFSI Loading Campaign Personnel Total Doses (neutron and
gamma) per ISFSI Program Area and Cask in mrem
MPC-127 MPC-123 MPC-126 MPC-121 MPC-124 MPC-120 MPC-125 MPC-122
Holtec 175 165 95 73 68 74 51 80
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MPC-127 MPC-123 MPC-126 MPC-121 MPC-124 MPC-120 MPC-125 MPC-122
PCI 70 44 30 24 23 26 21 21
Bragg 34 48 15 14 11 18 12 13
PM 1 0 0 0 0 1 0 0
MM 35 23 25 15 17 20 19 15
RP 52 23 24 18 13 10 14 7
DECON 32 12 7 10 7 4 5 4
OPS 0 4 3 7 0 0 0 0
ISI 0 0 0 0 0 0 0 0
Total 399 319 199 161 139 153 122 140
Comparing the 2009 to the 2010 and 2012 loading campaigns, the vast majority of dose
that was assigned to program management during the first campaign moved to the
Holtec group. The doses associated with mechanical & maintenance remained
statistically similar, while the PCI workers accumulated the second highest dose during
the 2010 cask loading campaign. Generally, the mrem per cask tended to trend
downward with each subsequent cask during the 2010 campaign. By the 2012
campaign, the mrem per cask average was 121 mrem/cask, which is comparable to
other region IV sites that use the Holtec HI-STORM 100 design.
Table 6, 2012 ISFSI Loading Campaign Personnel Total Doses (neutron and
gamma) per ISFSI Program Area and Cask in mrem
MPC-168 MPC-167 MPC-169 MPC-166 MPC-170 MPC-165 MPC-173
Holtec 75 62 47 34 68 67 54
PCI 12 16 14 6 9 14 14
Bragg 24 7 7 9 11 10 12
PM 5 3 2 2 5 3 4
MM 13 8 6 6 12 12 12
RP 18 7 12 7 9 13 14
DECON 20 8 16 8 22 15 19
OPS 0 0 0 3 0 0 0
ISI 0 0 0 0 0 0 0
Total 157 111 104 75 136 134 129
d. Neutron Monitoring
Three dosimeters were in active use at Diablo Canyon: the Panasonic UD-802, Panasonic
UD-813, and Panasonic UD-814. The Panasonic UD-802 is the primary dosimeter used to
measure personnel dose of legal record (DLR) for the majority of monitored personnel
onsite. The Panasonic UD-802 is a neutron sensitive TLD, but it was not optimized and
utilized for neutron sensitive activities at Diablo Canyon. The Panasonic UD-813
dosimeter was a custom designed dosimeter used at Diablo Canyon for ISFSI related
personnel monitoring and as an environmental TLD on the ISFSI pad. The Panasonic
UD-813 was a four-element TLD that had sundry filters on the front and back of its holder.
The front and rear filters were situated such that it measured neutrons incident from both
the front and rear of the badge when in use. The rear filters were intended to record the
albedo effect from the neutron dose. The albedo effect is related to the reflection of
incident neutrons off of the body of a monitored individual. The Panasonic UD-814 is a
dosimeter that is used by the RP staff to measure the radiological environmental dose at
both onsite and offsite locations. The Panasonic UD-814 dosimeter was configured to
measure gamma dose only.
In addition to the Panasonic UD-813 dosimeter used during loading activities, an
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electronic gamma/neutron dosimeter with a digital output was used by workers for dose
estimation and tracking purposes. The gamma and neutron doses reported by the
- 11 -
electronic dosimeters during the loading campaigns tracked statistically close with the
gamma and neutron doses reported by the Panasonic UD-813 dosimeter.
Diablo Canyon processed the sites personnel and environmental dosimetry. By
processing the dosimetry, Diablo Canyon had more control over the quality of its TLD
measurements. Based on interviews with dosimetry staff, Diablo Canyon managed to
control neutron doses to a lower threshold keeping the lower limits of detection for
neutron dose to within the range of 5-8 mrem.
The dosimetry records for the personnel associated with the 2010 cask loading activities
was reviewed to see how neutron doses compared to gamma and total doses. During
the 2010 ISFSI loading campaign total doses received by personnel was 531 mrem
gamma and 423 mrem neutron. For the 2010 loading campaign neutron dose
accounted for 44 percent of the total dose reported.
A review of PCI (welders and NDE staff) dose data for the 2010 loading campaign
showed that the dose tracked using the electronic dosimeters for gamma and neutron
correlated well with the dose reported by the Panasonic UD-813 dosimeter used for the
dose of legal record. The electronic dosimeters in use slightly overestimated the gamma
dose received by 8 percent and neutron dose received by 16 percent. The electronic
dosimetry reported a total dose of 106 mrem gamma and 153.6 mrem neutron to the PCI
personnel during the 2010 campaign. The actual dose recorded on the dose of legal
record for the PCI crew, tracked by the Panasonic UD-813 dosimeter, recorded 98 mrem
gamma and 132 mrem neutron.
e. Cask Records of Fuel Contents
A review of the Diablo Canyon ISFSI records was performed to determine if an adequate
description of the spent fuel loaded in the Holtec HI-STORM 100SA casks was
documented in the licensees records. The contents of each multi-purpose canister
(MPC) loaded into a HI-STORM 100SA cask at Diablo Canyon was documented in
DCPP Form 69-20428 Design Calculation Numbers: 9000040833, 9000041030,
9000041317, and number unassigned. These calculations had not yet received final
signoff, and were due to errors found in the CaskWorks program which is discussed in
Section 1.2.k of this report. The calculations contained fuel bundle specifications
including fuel type, decay heat, cooling time, initial U-235 enrichment, and burnup values
for each spent fuel bundle loaded into a canister at Diablo Canyon. Forms were
reviewed for all 23 loaded casks at the time of the inspection. The quality verification
program had also reviewed a random sample of these records in its 2011 Fuel
Management Audit, issued October 20, 2011 (see Section 1.2.a) and found that the
records were readily retrievable and complete.
f. Changes to the SNM-2511 License and FSAR
At the time of the last inspection in June of 2009, Diablo Canyon was utilizing SNM-2511
License Amendment 0 and FSAR Revision 2. Since then, Diablo Canyon has requested
and NRC approved two license amendment changes. The licensee has also revised the
FSAR twice in Revision 3 and Revision 4.
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Amendment 1 to Diablo Canyons SNM-2511 License was approved by the NRC on
February 10, 2010 (ADAMs Accession Number ML100360010). The major changes
associated with the amendment included: (1) Technical specification (TS) 3.1.4 was
removed from the license. TS 3.1.4 originally contained a time limit that prevented a
HI-STORM cask from being left in the cask transfer facility (CTF). The NRC reviewed
the supporting thermal analysis that was performed to remove TS 3.1.4 and concluded
the removal was acceptable since the fuel cladding temperature limits would not be
exceeded if left in the CTF; (2) TS 3.2.1 was changed to allow the use of linear
interpolation for determining the soluble boron concentration during loading operations.
Previously only two defined levels were defined in the TS; and (3) TS 3.1.1 helium leak
test was changed to be performed only on the vent/drain port cover plate welds vice the
lid weld and the vent/drain port cover welds. This was to provide consistency with the
leak rate testing requirements of Holtecs generic Certification of Compliance 1014,
Amendment 3.
Amendment 2 to Diablo Canyons SNM-2511 License was approved by the NRC on
January 19, 2012 (ADAMs Accession Number ML120260361). The major changes
associated with the amendment included: (1) the vacuum drying method was removed
from TS 3.1.1. Diablo Canyon only utilized the forced helium dehydration method for
drying canisters; (2) TS 3.1.4 Supplemental Cooling System was added to allow
loading of high burn-up fuel (fuel assemblies > 45,000 MWd/MTU); (3) TS 2.0 Approved
Contents was revised to reflect the addition of high burn-up fuel and a maximum decay
heat load for a MPC-32 canister to 750 Watts per assembly for a canister containing
high burn-up fuel; and (4) TS 2.0 Approved Contents was changed to allow the storage
of fuel assemblies with instrument tube tie rods and neutron source assemblies.
The two FSAR changes, Revision 3 and Revision 4, were performed to account for the
new license amendments that were reviewed and approved by the NRC in Amendments
1 and 2, respectively.
g. Isolation of Loaded Canisters, Holtec Information Bulletin (HIB) - 53
Holtec Information Bulletin HIB-53 was issued to the Holtec users on December 6, 2011.
The bulletin described an issue that was observed by NRC inspectors at the Waterford
nuclear plant (ADAMS Accession ML12124A387). While Waterford was loading its first
canister in late November 2011, operators isolated the canister by closing both the vent
and drain port caps during installation of the removable valve operating assemblies
(RVOAs). Having both port caps closed at the same time isolated the canister without
having any release path or relief valve available while the canister was filled with water
and fuel. This could have pressurized the canister due to the thermal heat of the spent
fuel. The Holtec bulletin reminded users that the vent and drain port caps should not be
closed simultaneously and that the remote valve operating assemblies must be installed
one at a time in the open position when the canister is filled with water. Holtec
Information Bulletin 53, under Urgency Level, the bulletin stated Users who are
currently in the process of loading should ensure the guidance in this document is
followed when processing the MPC. For those users who are not currently in the
process of loading, updates should be made to their procedures, if required based on
this guidance before the next loading.
- 13 -
In addition to HIB-53, issued in December 2011, prior to the 2012 loading campaign, the
licensees Quality Assurance (QA) organization had also identified this issue in a Quality
Verification Department audit of the Diablo Canyon Power Plant Technical Specification
Program conducted from July 6 through September 6, 2011. This audit was documented
in Memorandum File Net # 111800033 titled 2011 Technical Specification Audit, dated
October 5, 2011. However, no action was taken at that time to determine whether the
loading procedures could result in isolation of a loaded cask while containing water.
Diablo Canyons quality assurance audit documented that the Holtec canister design does
not have an isolation valve that could defeat pressure relief and create the potential for
over-pressure. This assessment did not address the use of the port caps to cause an
isolation event.
On March 19, 2013, the licensee became aware a third time of the Holtec bulletin to
ensure isolation of the canister would not occur during loading operations when the NRC
inspector emailed Diablo Canyon a list of topical areas that would be included in the
April 2013 ISFSI inspection. This list specifically referred to HIB-53. Upon receiving the
list of inspection items, the licensee reviewed HIB-53 and realized that no action had
been taken after receiving the bulletin in December 2011, over a year earlier and prior to
loading seven canisters during the 2012 loading campaign. The licensee placed the
missed opportunity to correct its loading procedures into the corrective action program
as SAPN 50466943 Task #7 on March 21, 2013.
The Diablo Canyon Procedure HPP-1073-300 Procedure for Drying, Backfill, and
Sealing the MPC at DCPP, Revision 9 dated October 28, 2011 was not updated to
comply with the HIB-53 prior to Diablo Canyons third loading campaign which loaded
seven casks from January 24, 2012 through March 17, 2012. Procedure HPP-1073-300
Step 6.3.2 directed personnel to install the MPC lid drain/vent port caps by verifying
each of the caps were fully seated. This step resulted in the canister being in an isolated
condition. At that time, the canister lid had been installed and welded and the canister
was filled with water except for the approximately 50 gallons that was removed prior to
welding of the lid. As long as the vent and drain port caps were fully seated there was
no pressure relief valve in line to provide for over-pressurization relief. The procedure
relieved this situation in Step 6.3.19 after the drain port removable valve operator
assembly (RVOA) was installed over the drain port cap and the operating rod was used
to open the drain port and provide a vent to the canister. The estimated time period a
canister was in an isolated condition has been approximated to about forty to sixty
minutes. Since the isolation period was of short duration the resulting pressure increase
inside the canister would have been low.
A review of Diablo Canyons FSAR found no discussion of isolating the canister during
operations or any accident analysis that evaluated buildup of pressure in the canister
during isolation due to the heating effect of the spent fuel on the water inside the
canister. FSAR Section 8.2.14.2 Accident Analysis discussed a hypothetical event of
the failure of all the fuel rods during storage/transportation. In this condition no water
was in the canister and the pressure build-up was due to the pressure that had escaped
from inside the fuel rods. This resulted in a maximum pressure of 166.1 psig for a
MPC-32 canister containing PWR fuel with a 24 kW total heat load. This was identified
as being less than the MPC accident design pressure of 200 psig.
- 14 -
Buildup of pressure inside the canister due to heating of the water by the spent fuel while
the canister is isolated is not analyzed in the Diablo Canyon ISFSI FSAR. Following
Procedure HPP-1073-300 Step 6.3.2 through Step 6.3.19 resulted in a period of time
that the canister was isolated. The FSAR, Chapter 5 ISFSI Operations describes the
operations for loading a cask. These steps do not place the canister in an isolated
condition with water still in the canister. The licensee failed to perform an adequate
safety review per 10 CFR 72.48 to ensure the Procedure HPP-1073-300 followed the
procedures as outlined in Chapter 5 of the FSAR.
Federal regulations in 10 CFR 72.48(c)(1) and (c)(2)(v) states that a licensee may make
changes in the facility or spent fuel storage cask design as described in the FSAR, make
changes to procedures as described in the FSAR, and conduct tests or experiments not
described in the FSAR without obtaining a license amendment if the change, test, or
experiment does not create a possibility for an accident of a different type than any
previously evaluated in the FSAR.
Contrary to the above requirement, from late January 2012 through March 2012, the
licensee failed to follow procedures as described in the FSAR and created a possibility
for an accident not previously evaluated in the FSAR, without obtaining a license
amendment change. Specifically, Diablo Canyons , Procedure HPP-1073-300 included
steps that were not consistent with Chapter 5 of the FSAR and resulted in the isolation of
the canister, while filled with water, which created the possibility of an accident not
evaluated in Chapter 8 of the FSAR. Diablo Canyon used this procedure to load seven
casks from January 2012 to March 2012. This was determined by the NRC as a
Severity Level IV violation in accordance with the guidance set forth in Section 2.2.2 of
the Enforcement Policy. The violation is being cited in the Notice because Diablo
Canyon was notified of a potential non-compliance in its procedure by the cask
vendor (Holtec), failed to restore compliance within a reasonable period of time, failed to
place the issue in the corrective action program in a timely manner before the 2012
campaign, and proceeded to use the procedure that placed seven canisters from
January 2012 through March 2012 in an unanalyzed condition.
On April 24, 2013, Diablo Canyon issued Licensee Event Report Notification 48965 that
documented that their loading procedures had placed canisters in an isolated condition
which was not analyzed in the Diablo Canyon FSAR.
h. Technical Specification 3.1.2 Temperature Monitoring
Technical Specification 3.1.2 required each casks heat removal system to be operable
during storage on the ISFSI pad. Surveillance Requirement 3.1.2.1 required the
licensee to verify daily the inlet and outlet duct screens are free of blockage. The
licensee utilized Procedure STP I-1A Routine Shift Checks Required by Licenses,
Revision 125 to comply with the Technical Specification. The Procedure STP I-1A
Attachment 12.1 MODE 1 Shift Checklist required operators to verify all inlets and
outlets for each cask loaded on the ISFSI pad was free of blockage.
Documentation was reviewed for the months of September 2010, December 2011,
February 2012, and July 2012 for compliance with Technical Specification 3.1.2. Of the
four months selected for review, the licensee provided documentation that showed the
casks were verified as operable and free from blockage.
- 15 -
i. Corrective Action Program
A list of condition reports issued since the last NRC inspection in June of 2009 was
provided by the licensee for the fuel handling building crane and the ISFSI. Issues were
processed in accordance with Procedure OM7.ID1 Problem Identification and
Resolution, Revision 42. When a problem was identified the licensee would document
the issue as a condition report in the Systems Application and Process Notification
(SAPN) database and assign a SAPN number to track the issue.
Of the list of condition reports (SAPNs) provided relating to the ISFSI and the fuel
handling building crane, approximately 50 SAPNs were selected by the NRC for further
review. The SAPNs related to a number of different topics including: failure of a
wedgelock assembly on the tower of the Vertical Cask Transporter during loading
operations, forced helium dehydrator skid failure during loading operations, the canister
downloader slings were discovered damaged and were sent to the manufacturer for
repair/recertification, fuel handling building crane troubleshooting, issues discovered by
Westinghouse related to the CaskWorks program, a hydraulic pump on the Vertical Cask
Transporter failed, paint flaking off the HI-TRAC transfer cask, small cracks found on
non-structural welds of the Vertical Cask Transporter, loading problems identified during
the 2nd loading campaign, crew ALARA dose goals were not met for Cask # 9, and
issues regarding loose HI-STORM hold-down nuts found on the ISFSI pad.
The SAPNs reviewed were well documented and properly categorized based on the
significance of the issue. The corrective actions taken were appropriate for the
situations. Based on the level and detail of the corrective action reports, the licensee
demonstrated a high attention to detail in regards to the maintenance and operation of
their ISFSI program and fuel handling building crane. The high number of SAPNs and
the SAPN issues reviewed by the inspectors reflected a low thresh-hold to place issues
in the corrective action program. No NRC concerns were identified related to the
condition reports reviewed.
j. Annual Inspections of the HI-STORM Casks
The Diablo Canyon ISFSI FSAR Section 4.2.3.1 Function states the maintenance
programs of the HI-STORM 100 System are specified in Chapter 9 of the HI-STORM
100 FSAR. The Holtec HI-STORM 100 FSAR Chapter 9 Table 9.2.1 HI-STORM
System Maintenance Program Schedule required users to perform an annual inspection
of each casks external surface on an annual basis. Diablo Canyon utilized Procedure
PEP DF-12 HI-STORM Annual Inspection Revision 1 to perform the annual inspection
of the casks loaded on the ISFSI pad. The NRC Inspectors reviewed the inspection
documentation for years 2011 and 2012. The 2011 annual inspection was documented
Work Order No. 64057344, dated September 29, 2011 and the 2012 annual inspection
was documented in Work Order No. 64079851, dated October 1, 2012. All issues that
were identified during the inspection, such as, anchor bolt corrosion, cask coating
repairs, and other miscellaneous items were placed in the licensees corrective action
program for resolution. All deficiencies identified were minor and did not affect the
function of the casks to perform their safety function.
- 16 -
k. CastWorks Provided Non-Conservative Decay Heat Values
On January 18, 2012, Diablo Canyon received an email from Westinghouse, the vendor of
CaskWorks that discussed a generic issue. Diablo Canyon utilized Westinghouses
program, CaskWorks, to evaluate fuel assembly characteristics, such as burnup and
decay heat for compliance to with their Licenses Technical Specifications. Westinghouse
revealed in the email that certain program files used for calculating a fuel assemblys
decay heat referenced Boiling Water Reactor (BWR) fuel assembly values in the program
code instead of PWR fuel assembly values. Diablo Canyon was one of the sites listed in
the email that was affected by this discrepancy. The program code issue resulted in non-
conservative decay heat values that could be off by as much as 2 percent from the correct
value. The email then described how Westinghouse would correct the program code for
all users that were affected.
Upon receiving the email, Diablo Canyon issued condition report SAPN 50453662 dated
January 23, 2012 to address the discrepancy. In the SAPN Diablo Canyon documented
that per ISFSI FSAR Section 3.1.1.2 Thermal and Radiological Characteristics, Diablo
Canyon already applied a 5 percent conservative burnup uncertainty when calculating the
decay heat for a fuel assembly loaded in a canister. Since the notification from
Westinghouse stated the difference in decay heat was expected to be less than
2 percent, Diablo Canyons conservative calculation would still be higher than the actual
decay heat, ensuring no limits were exceeded. To maintain compliance with the FSAR
Section 3.1.1.2, the licensee was in the process of recalculating the decay heat values of
all assemblies loaded into the 23 HI-STORM casks to still include the 5 percent
conservatism. This action was being tracked by SAPN 50453662. Inspectors reviewed
the latest calculations, DCPP Form 69-20428 Design Calculation Numbers: 9000040833,
9000041030, 9000041317, and number unassigned, which determined the new decay
heat values for each assembly and cask. These calculations had not yet received final
approval. No individual fuel assembly or total cask heat load values exceeded the
technical specifications with the 2 percent increase.
l. Decommission Funding Plan
Federal Register Notice 76FR35512, dated June 17, 2011, included a new rulemaking
requirement that affected Part 72 licensees. The Federal Register documented a change to
72.30(b) which required Part 72 licensees to submit to the NRC for review and approval an
ISFSI decommissioning funding plan. The final rule made changes to the financial
assurance requirements for Part 72 licensees to provide greater consistency with similar
decommissioning requirements in the 10 CFR Part 50 regulations. Financial assurances
are financial arrangements provided by the licensee to ensure funds for decommissioning
will be available when needed. The effective date of the new rule was December 17, 2012.
The new rule required all Part 72 licensees to submit a decommissioning funding plan to the
NRC by the effective date of the rule. Diablo Canyon submitted its ISFSI Decommissioning
Funding Plan to the NRC for review and approval on December 17, 2012 (Adams Accession
No. ML12353A315) in compliance with the new rule.
m. NRC Information Notice 2012-20
On November 14, 2012, NRC issued Information Notice 2012-20, Potential Chloride-
Induced Stress Corrosion Cracking of Austenitic Stainless Steel and Maintenance of Dry
Cask Storage System Canisters, to all holders of and applicants for an ISFSI license or
- 17 -
Certificate of Compliance under 10 CFR Part 72. The notice required no action, but
discussed the occurrence of chloride induced stress corrosion cracking in stainless steel
welds on various piping components at four nuclear sites within a close proximity to salt
water bodies. Those sites were San Onofre Nuclear Generating Station, St. Lucie
Nuclear Power Plant, Turkey Point Nuclear Generating Station, and Koeberg Nuclear
Power Station (South Africa).
The Information Notice discussed the stress corrosion cracking failures that have been
documented thus far at nuclear facilities and the environmental and chemical conditions
that contribute to the failures. Since the storage canisters use the same types of
stainless steel and welding materials as the piping that was found to contain stress
corrosion cracking, the IN provided information specific to ISFSI sites on the conditions
that have lead to those failures. The notice documented that no instances of stress
corrosion cracking have been reported on spent fuel canisters by the industry or the
NRC.
Diablo Canyon received the Information Notice and entered it into the corrective action
program by issuing SAPN 50525427 on November 27, 2012. The SAPN 50525427
discussed how Diablo Canyon and the nuclear industry as a whole has been aware of
the stress corrosion cracking issues and how they support research into the cause of the
problem and the development of a comprehensive plan to address the issue. After
completion of the research and development, Diablo Canyon planned on developing an
appropriate aging management plan to address stress corrosion cracking on canisters at
the site.
Diablo Canyons response to NRC Information Notice 2012-20 has been adequately
captured and documented in the corrective action program.
1.3 Conclusions
The licensee was conducting quality assurance audits of the ISFSI program. A review of
four audit reports determined that the audits were covering a broad range of topics. A
number of issues were identified in the audits and entered into the corrective action
program for resolution.
Radiation levels around the ISFSI pad were within expected ranges for a site with
23 casks in storage. For the environmental monitoring periods of 2009, 2010, and 2011,
the dose from the ISFSI had no effect on dosimetry located between the ISFSI and the
site boundary.
Documents and records related to the 2009, 2010, and 2012 ISFSI cask loading
campaigns were reviewed. Information included personnel dosimetry records, total
personnel dose received per cask loading, and neutron doses received by workers
during cask loading activities. Worker doses to load a cask have continued to decrease
from previous loadings, with the last campaign averaging 0.121 person-rem/cask.
Diablo Canyon was recording measurable neutron dose that ISFSI workers received
during the loading campaigns through the use of the Panasonic UD-813 dosimeter. The
Panasonic UD-813 dosimeters used for measuring personnel dose of legal record were
noted to have recorded doses which were statistically close to the data from the
electronic alarming dosimeters worn by the workers for both gamma and neutron dose.
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Required records were maintained that described the specific fuel parameters for the
spent fuel stored in each of the licensees loaded casks.
Since the last NRC ISFSI inspection Diablo Canyon has requested and NRC approved
two license amendment changes and had revised the ISFSI FSAR twice in Revision 3
and Revision 4. No issues were identified in review of these changes.
The FSAR does not include an accident analysis for a situation where the canister is filled
with water after the lid is welded in place, with the vent and drain port caps closed, which
resulted in an isolated condition. The licensee failed to perform an adequate safety review
per 10 CFR 72.48 to ensure the Procedure HPP-1073-300 followed the process as outlined
in Chapter 5 of the FSAR. Federal regulations in 10 CFR 72.48(c)(1) states, in part, that a
licensee may make changes to procedures as described in the FSAR, if the change does
not create a possibility for an accident of a different type than any previously evaluated in
the FSAR. Contrary to this, the licensee failed to follow procedures as described in the
FSAR and created a possibility for an accident not previously evaluated in the FSAR. This
was determined by the NRC to be a Severity Level IV violation. The violation was cited in
the Notice of Violation because Diablo Canyon was notified of a potential non-compliance
in its procedure by the cask vendor (Holtec) and failed to restore compliance within a
reasonable period of time, failed to place the issue in the corrective action program prior to
the 2012 campaign, and proceeded to use the procedure that placed seven canisters in an
unanalyzed condition from January 2012 through March 2012.
Technical Specification 3.1.2 vent inspection requirements for the HI-STORMs were
performed daily as required.
Selected condition reports were reviewed for the period June 2009 through April 2013. A
wide range of issues had been identified and resolved. Resolutions of the issues were
appropriate for the safety significance of the issue. No adverse trends were identified
during the review.
Annual cask inspections had been completed in accordance with FSAR requirements.
Only minor deficiencies were identified and placed in the corrective action program for
resolution.
Westinghouse identified an issue with CaskWorks, a program utilized by Diablo Canyon
for analysis of the fuel assemblies characteristics. The issue was placed in the
corrective action program and appropriately resolved.
Diablo Canyons response to NRC Information Notice 2012-20 has been adequately
captured and documented in the corrective action program.
Diablo Canyon submitted its ISFSI Decommissioning Funding Plan in compliance with
10 CFR 72.30(b) on the submittal deadline of December 17, 2012.
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2 Review of 10 CFR 72.48 Evaluations (60857)
2.1 Inspection Scope
The licensees 10 CFR 72.48 screenings and evaluations since the 2009 NRC ISFSI
inspection were reviewed to determine compliance with regulatory requirements.
2.2 Observations and Findings
A list of modifications to the ISFSI program and changes to the fuel handling building
crane were provided by the licensee. Five 10 CFR 72.48 screenings were selected for
further review and four 72.48 full evaluations were selected for review. The licensee
utilized Procedure TS3.ID2 Licensing Basis Impact Evaluations, Revision 34A to
perform the 10 CFR 72.48/50.59 safety screenings or evaluations. The issues
discussed in the screenings selected for review included the following: revision and
addition of design output documents from Holtec; the correction of inconsistencies in the
FSAR; changes made to the FSAR that were approved by the NRC in License
Amendments 1 and 2; and the allowance for a MPC to be placed 90 degrees from the
normal orientation in a HI-STORM.
The four 72.48 Evaluations that had been performed since the last inspection were
reviewed. All four of the evaluations were reported to the NRC in PG&E letter
DIL-12-002 Materials License No. SNM-2511, Docket No. 72-26 Diablo Canyon ISFSI
10 CFR 72.48 Report of Changes, Tests, and Experiments for March 1, 2010 to
February 29, 2012, dated March 15, 2012 (Adams Accession Number ML12075A077).
Each of the following safety evaluations documented that the proposed change did not
require NRC approval.
Safety evaluation Licensing Basis Impact Evaluation (LBIE) 2010-004 dated April 26, 2010,
documented an upgrade to the vertical cask transporter. The upgrade redesigned the
wedge assemblies located in the lift towers which lock the towers in case of a power failure.
The new design was spring-engaged like the existing design but was released with
hydraulic versus electromechanical force. Also the display system was upgraded to a new
digital control system that contained enhanced features.
Safety Evaluation LBIE 2010-006 dated May 1, 2010, documented the addition of shim
plate weldments onto the bottom of the storage casks base-plate to ensure flatness of
the matting contact surface with the ISFSI pad and changes in the thread size of the
storage casks lid anchor block to accommodate the thickness of an applied coating that
reduced bolt binding.
Safety Evaluation LBIE 2010-010 dated June 24, 2010, documented non-conformances
on HI-STORM casks serial numbers 316 and 321. This was attributed to supplier
fabrication welding issues that were dispositioned as Accept-As-Is. The changes were
determined to be within the bounds of the approved structural analyses in the Diablo
Canyon FSAR.
Safety Evaluation LBIE 2011-003 dated February 16, 2011, documented the placement
of six bullet and blast resistant enclosure guard towers around the plants protected area
perimeter to enhance the plants security system.
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2.3 Conclusions
All required safety screenings and safety evaluations had been performed in accordance
with procedures and 10 CFR 72.48 requirements except for the issue discussed in
Section 1.2.g of this report. All other screenings and safety evaluations reviewed were
determined to be adequately evaluated.
3 Followup (IP 92701)
(Closed) Licensee Event Report 47580/PG&E-NRC, loose anchor stud nuts found on
casks:
On January 9, 2012, during a walk around on the ISFSI pad, a Diablo Canyon employee
noted that a nut on one of the hold down bolts of cask #12 (HI-STORM Serial Number
229-317) was loose. The deficiency was discovered while performing the monthly vent
inspection on the upper and lower vents for each HI-STORM. These hold down bolts
secure the HI-STORMs to the ISFSI pad to ensure the HI-STORM remains in place if an
earthquake were to occur. The operator checked and confirmed the rest of the bolts for
cask #12 were tight and initiated condition report SAPN 50451401, dated January 9, 2012.
Per FSAR Section 4.2.1.1.6, each cask is compressed against the embedment plate on
top of the ISFSI pad using 16 studs. Each stud is preloaded to approximately 157,000
pounds force (lbf) after a cask is placed on the ISFSI pad. The licensee noted that an
analysis was performed previously in Holtec Calculation HI-2012618 Revision 11
(PG&E Calc. 9*8541, Revision 1) determined that any cask would still maintain stability
during a seismic event even if all 16 hold down stud nuts were installed with no pre-load.
However, that analysis was not referenced or referred to in the FSAR.
Upon discovery of the loose nut the licensee reviewed its FSAR and Technical
Specifications and Diablo Canyon determined that the loose nut did not meet the
licensing basis. Therefore, at that time the cask was declared nonfunctional with the
safety function of having all studs meeting Section 4.2.1.1.6. of the FSAR. Diablo
Canyon initiated Licensee Event Report (LER) Notification 47580, dated January 9, 2012
and reported the situation to the NRC (Adams Accession No. ML12069A015).
On January 10, 2012 the licensee re-tensioned all 16 nuts on cask #12 following the
approved tensioning pattern used for placement of a cask on the pad. Based on the
discovery of the discrepant nut on cask #12, an extent of condition evaluation was
conducted by Diablo Canyon. On January 11, 2012, plant personnel notified Diablo
Canyon shift manager that two additional nuts on hold-down studs for two other HI-
STORM casks were discovered to be loose. The two additional nuts (one per cask)
were discovered when personnel used the full effort of two hands to check all 16 nuts on
all 16 cask that were on the ISFSI pad at that time. This issue was updated to the NRC
the same day of discovery through an update to the Licensee Event Report Notification
47580. After discovery of the two additional loose nuts, the licensee completed actions
to re-tension all nuts on all 16 casks. No additional loose nuts were reported.
The licensee attributed the loose nuts to inadequate cleanliness prior to final tensioning.
The licensee SAPN documented that the introduction of a medium grade grain of sand in
the bearing area may create a condition that would prevent long term maintenance of
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the stud tension forces. The licensee adequately addressed and implemented
appropriate corrective actions for the loose anchor stud nuts. To address the issue the
licensee implemented the following corrective actions: (1) revised Procedure HPP-1073-
400 Procedure for MPC Transport at Diablo Canyon to include instructions for cleaning
the underside of the HI-STORM and the embedment ring prior to final positioning of the
cask; (2) Procedure HPP-1073-400 was changed to direct personnel to re-tension all
studs in a second pass after performing the first pass after removing the Vertical Cask
Transporter away from the HI-STORM; and (3) Procedure PEP DF-12 HI-STORM
Annual Inspection was revised to check all anchor stud nuts for looseness on each cask
annually.
4 Exit Meeting
The inspectors reviewed the scope and findings of the inspection during an exit
conducted on April 30, 2013.
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SUPPLEMENTAL INSPECTION INFORMATION
PARTIAL LIST OF PERSONS CONTACTED
Licensee Personnel
T.Baldwin, Department Manager, Regulatory Services
J. Felice, RP Foreman, Radiation Protection Group
S. Flickinger, Used Fuel Project Manager, Strategic Projects
R. Hagler, Engineering Supervisor, Strategic Projects
E. Halpin, Chief Nuclear Officer
M.McCoy, NRC Interface, Regulatory Services
L. Million, RP General Foreman, Radiation Protection Group
L. Pulley, Used Fuel Storage Manager, Strategic Projects
L. Sewell, Principle Engineer, Radiation Protection
INSPECTION PROCEDURES USED
IP 60855.1 Operations of an ISFSIs at Operating Plants
IP 60857 Review of 10 CFR 72.48 Evaluations
IP 92701 Followup
LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED
Opened
72-26/1301-01 NOV Isolated the canister and placed canister in an
unanalyzed condition, violation of 72.48(c)(2)(v),
LER 48965/PG&E-NRC LER Licensee Event Report Notification 48965,
procedures had placed canisters in an unanalyzed
condition.
Discussed
None
Closed
LER 47580/PG&E-NRC LER Licensee Event Report Notification 47580, loose
anchor stud nuts found on casks.
Attachment 1
LIST OF ACRONYMS
ADAMS Agencywide Documents Access and Management System
ASME American Society of Mechanical Engineers
BWR Boiling Water Reactor
CFR Code of Federal Regulations
CTF cask transfer facility
DECON decontamination
DCPP Diablo Canyon Power Plant
DLR dose of legal record
DNMS Division of Nuclear Material Safety
EA Enforcement Action
FSAR Final Safety Analysis Report
HIB Holtec Information Bulletin
IP inspection procedure
ISFSI Independent Spent Fuel Storage Installation
ISI in service inspection
kW kilo-watt
lbf pounds force
LBIE licensing basis impact evaluation
LER Licensee Event Report
M&M mechanical and maintenance
mR milliRoentgen
micro(µ)R/hr microRoentgen per hour
micro(µ)rem/hr microRoentgen equivalent man per hour
MPC multipurpose canister
mrem milliRoentgen equivalent man
MWD/MTU megawatt days/metric ton uranium
NDE non-destructive examination
NOV Notice of Violation
NRC U.S. Nuclear Regulatory Commission
OPS operations
PG&E Pacific Gas and Electric
PM project management
PWR pressurized water reactor
QA quality assurance
REOP Radiological Environmental Operating Report
RP radiation protection
RVOA remote valve operating assembly
SA Short Anchored
SAPN system application and process notification
TLD thermo-luminescent dosimeter
TS technical specification
WO work order
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ATTACHMENT 2:
LOADED CASKS AT THE DIABLO CANYON POWER PLANT ISFSI
LOADING HI-STORM MPC DATE HEAT LOAD BURNUP MAXIMUM FUEL PERSON-REM
Unit
ORDER ID No. ID No. ON PAD (kW) MWd/MTU (max) ENRICHMENT % DOSE
1 103 20 1 6/23/09 18.85 44,888 4.61 .370
2 91 12 1 6/30/09 18.92 44,352 4.62 .274
3 80 10 1 7/8/09 20.12 44,967 4.10 .316
4 102 14 1 7/18/09 20.19 44,029 4.10 .245
5 93 17 1 7/26/09 20.21 44,718 4.10 .253
6 95 21 1 8/2/09 20.26 44,999 4.10 .239
7 78 65 1 8/10/09 20.29 44,769 4.10 .196
8 100 8 1 8/17/09 19.07 44,966 4.09 .169
9 322 127 2 5/13/10 19.60 44,864 4.42 .399
10 318 123 2 5/29/10 20.10 44,786 4.41 .319
11 320 126 2 6/6/10 20.16 44,641 4.42 .199
12 317 121 2 6/12/10 20.21 44,922 4.43 .161
13 319 124 2 6/19/10 19.58 44,841 4.12 .139
14 323 120 2 6/26/10 19.63 44,963 4.12 .153
Attachment 2
LOADING HI-STORM MPC DATE HEAT LOAD BURNUP MAXIMUM FUEL PERSON-REM
Unit
ORDER ID No. ID No. ON PAD (kW) MWd/MTU (max) ENRICHMENT % DOSE
15 321 125 2 7/3/10 19.65 44,798 4.12 .122
16 316 122 2 7/10/10 19.69 44,710 4.12 .140
17 513 168 1 1/30/12 12.54 47,683 4.10 .167
18 510 167 1 2/12/12 12.71 47,845 4.09 .111
19 506 169 1 2/19/12 13.07 47,398 4.09 .104
20 514 166 2 2/26/12 12.25 46,134 3.73 .075
21 516 170 2 3/5/12 15.38 47,195 4.10 .136
22 507 165 2 3/11/12 16.03 47,018 4.11 .134
23 508 173 2 3/17/12 16.48 46,983 4.11 .129
NOTES: Heat load (kW) is the sum of the heat load values for all spent fuel assemblies in the cask
Burn-up is the value for the spent fuel assembly with the highest individual discharge burn-up
Fuel enrichment is the spent fuel assembly with the highest average initial enrichment percent of U-235
Casks #1 through 8 were loaded to SNM-2511, License Amendment 0, and the Updated Final Safety Analysis Report, Revision 2.
Casks #9 through 16 were loaded to SNM-2511, License Amendment 1, and the Updated Final Safety Analysis Report, Revision 3.
Casks #17 through 23 were loaded to SNM-2511, License Amendment 2, and the Updated Final Safety Analysis Report, Revision 3.
All casks are maintained under SNM-2511, License Amendment 2, and the Updated Final Safety Analysis Report, Revision 4.
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