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 inform
ation 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 pot
ential 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 NRC's 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:
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