Information Notice 2014-08, Need for Continuous Monitoring of Active Systems (Including Vacuum Drying Process)
| ML14121A089 | |
| Person / Time | |
|---|---|
| Issue date: | 05/16/2014 |
| From: | Mark Lombard NRC/NMSS/SFST |
| To: | |
| Solis J | |
| References | |
| IN-14-008 | |
| Download: ML14121A089 (4) | |
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, DC 20555-0001 May 16, 2014 NRC INFORMATION NOTICE 2014-08: NEED FOR CONTINUOUS MONITORING OF
ACTIVE SYSTEMS IN LOADED SPENT FUEL
STORAGE CANISTERS (INCLUDING VACUUM
DRYING PROCESS)
ADDRESSEES
All holders of and applicants for an independent spent fuel storage installation license under
Title 10 of the Code of Federal Regulations (10 CFR) Part 72, Licensing Requirements for the
Independent Storage of Spent Nuclear Fuel, High-Level Radioactive Waste, and Reactor- Related Greater than Class C Waste, 10 CFR Part 72 Certificate of Compliance holders, and
all 10 CFR Part 72 general licensees.
PURPOSE
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to
supplement IN 2011-10 Thermal Issues Identified during Loading of Spent Fuel Storage Casks
to inform addressees of additional information and lessons learned pertaining to the incident
that occurred during the loading of spent fuel storage canisters at the Byron Generating Station.
NRC expects that recipients will review the information for applicability to their facilities and take
actions, as appropriate, to avoid similar problems. Suggestions contained in this IN are not NRC
requirements; therefore, no specific action or written response is required.
DESCRIPTION OF CIRCUMSTANCES
On August 28-29, 2010, a Holtec HI-STORM 100 spent fuel storage system multipurpose
canister containing fuel assemblies and located within a transfer cask was left unattended for
the evening. A cooling system, which circulated water in the annulus between the canister and
transfer cask to keep cladding temperatures below allowable limits, was found to be inoperable
the next morning. The NRC conducted a reactive team inspection at the Byron Generating
Station in September 2010, and issued Inspection Report Nos. 05000454/2010007,
05000455/2010007, and 07200068/2010002 (Agencywide Documents Access and
Management System (ADAMS) Accession No. ML103140226). Issues that arose as a result of
the reactive team inspection were also addressed during a scheduled design and quality
assurance inspection at Holtec International, who holds the HI-STORM 100 Certificate of
Compliance, from October 25 -29, 2010 (Inspection Report No. 72-1014/10-201, ADAMS
Accession No. ML110450157).
ML14121A089 On May 2, 2011, the NRC issued Information Notice 2011-10 (ADAMS Accession No.
ML111090200) to inform addressees of the incident that occurred during the loading of spent
fuel storage canisters at the Byron Generating Station. In this information notice the NRC
expected that recipients would review the information for applicability to their facilities and take
actions, as appropriate, to avoid similar problems.
However, after issuing IN 2011-10, the NRC continued to have technical discussions regarding
the vulnerability of unattended vacuum drying process. On February 6, 2014, the NRC held a
public meeting at NRC headquarters to discuss potential safety issues associated with the
vacuum drying process during spent nuclear fuel cask loading operations (ADAMS Accession
No. ML14065A014). During the public meeting the NRC provided an overview of potential
issues associated with the Byron Generating Station event and a representative from the utility
provided an overview of the event and actions taken at the Byron Generating Station. A
representative from the Nuclear Energy Institute provided an overview related to the safety
significance of the event and actions taken by industry in response to IN 2011-10. In general
these actions meet NRCs expectations that the vacuum drying process should be continuously
monitored during all phases. As a result of the public meeting, the NRC learned what actions
have been taken by industry in response to IN 2011-10 and what type of additional information
need to be provided in this supplement, as described below.
DISCUSSION
The inspection reports referenced above provide detailed summaries of the incident as well as
findings and observations, underlying implications, and other information. As a result of the
inspections, subsequent reviews and technical analyses, IN 2011-10, and discussions during
the public meeting held on February 6, 2014, the NRC identified unresolved potential safety
issues related to the incident:
(1) A loaded spent fuel storage cask was left unattended with an inoperable cooling system.
Even though vacuum drying was secured when the cooling system failure occurred, the
entire process was put at risk because the cooling system failure went undetected for an
entire night, which resulted in an uncontrolled temperature increase inside the canister.
(2) Subsequent failure of the cooling system resulted in the licensee not being in compliance
with the cask technical specifications of ensuring that the peak cladding temperature is
maintained below recommended limits and that the spent fuel is maintained under flooded
or inert conditions if a failure of the vacuum drying system occurred.
In summary, cask vendors and licensees should review their operating procedures to ensure
they are adequate to maintain peak cladding temperature below recommended limits during
vacuum drying. To achieve these objectives, the cask operating procedures should also be
reviewed to determine if they adequately address the need for continuous monitoring of the
vacuum drying process. Cask vendors and licensees should consider the need for continuous
monitoring of the vacuum drying process such that operators are available to take any
necessary actions to put the system into compliance with technical specifications, if a system
failure occurred. The monitoring can be done by means other than direct observation.
CONTACT
This IN requires no specific action or written response. Please direct any questions about this
matter to the technical contact listed below.
/RA/ A. Hsia for
Mark Lombard, Director
Division of Spent Fuel Storage and Transportation
Office of Nuclear Material Safety
and Safeguards
Technical Contact:
Jorge Solis, NMSS/SFST/TCB
301-287-9094 E-mail: Jorge.Solis@nrc.gov
Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under Electronic Reading Room/Document Collections.
CONTACT
This IN requires no specific action or written response. Please direct any questions about this
matter to the technical contact listed below.
/RA/ A. Hsia for
Mark Lombard, Director
Division of Spent Fuel Storage and Transportation
Office of Nuclear Material Safety
and Safeguards
Technical Contact:
Jorge Solis, SFST
301-287-9094 E-mail: Jorge.Solis@nrc.gov
Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under Electronic Reading Room/Document Collections.
G:\SFST\Solis\IN-2014-008-ML14121A089.doc
ADAMS P8 Accession No.: ML14121A089 OFC: NMSS E NMSS E NMSS E NMSS E NMSS E NMSS E
NAME: JSolis CAraguas MSampson REinziger THsia MLombard
DATE: 04/29/14 04/29/14 04/30/14 05/01/14 05/01/14 05/16/14 OFFICIAL RECORD COPY