ML13246A358
| ML13246A358 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 11/07/2013 |
| From: | Anthony Mendiola NRC/NRR/DPR/PSPB |
| To: | Technical Specifications Task Force |
| Honcharik M, 301-415-1774 | |
| References | |
| Download: ML13246A358 (5) | |
Text
November 7, 2013 Technical Specifications Task Force (TSTF) 11921 Rockville Pike, Suite 100 Rockville, MD 20852
SUBJECT:
POTENTIAL ISSUES WITH PLANT-SPECIFIC ADOPTION OF TRAVELERS TSTF-51, REVISION 2, REVISE CONTAINMENT REQUIREMENTS DURING HANDLING IRRADIATED FUEL AND CORE ALTERATIONS, TSTF-286, REVISION 2, "OPERATIONS INVOLVING POSITIVE REACTIVITY ADDITIONS," AND TSTF-471, REVISION 1, ELIMINATE USE OF TERM CORE ALTERATIONS IN ACTIONS AND NOTES
Dear Members of the TSTF:
The purpose of this letter is to inform the TSTF of concerns that the U.S. Nuclear Regulatory Commission (NRC) staff has recently identified during a review of plant-specific license amendments requesting adoption of the subject Travelers.
Traveler TSTF-51, Revision 2, Revise Containment Requirements during Handling Irradiated Fuel and Core Alterations, was approved on November 1, 1999 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML993190284). Traveler TSTF-51 removed the defined term Core Alterations from the Standard Technical Specifications (STS).
In Standard Technical Specifications, Revision 1.1, Definitions, the term Core Alteration was defined as the movement of any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel. Suspension of Core Alterations shall not preclude completion of movement of a component to a safe position.
TSTF-286, Revision 2, Operations Involving Positive Reactivity Additions, was approved on July 6, 2000 (ADAMS Accession No. ML003730788). Traveler TSTF-286 revised the limiting condition for operation (LCO) Actions and Notes that require suspension of operations involving positive reactivity additions or preclude reduction in boron concentration by placing a limit on positive reactivity addition to within the TS-required shutdown limit. Thus, TSTF-286 provides the flexibility necessary for continued safe reactor operations, while also limiting any potential for excessive positive reactivity addition to the core.
TSTF-471, Revision 1, Eliminate Use of Term Core Alterations in Actions and Notes, was approved on December 7, 2006 (ADAMS Accession No. ML062860320). Traveler TSTF-471 corrected an oversight related to implementation of TSTF-51 above. TSTF-51 was intended to delete any reference to the term Core Alterations in the TS. Following TSTF-51 implementation, the industry noted other places in the TS where the term continued to exist.
Traveler TSTF-471, (a) eliminated the term Core Alteration, from these remaining references, and (b) removed the requirement to Suspend Core Alterations from several specific STS sections on electrical and refueling operations related to the plant Refueling, mode of operations.
TSTF During the NRCs review of license applications to adopt the subject Travelers, the NRC staff has identified potential operating issues. The NRC staffs concerns relate to core monitoring instrumentation and dose consequences, as stated below:
- a. NUREG-0800, The Standard Review Plan for the Review of Safety Analysis Reports [SAR]
for Nuclear Power Plants: LWR [Light Water Reactor] Edition - Transient and Accident Analysis (SRP Chapter 15) Section 15.4.6, Inadvertent Decrease In Boron Concentration in the Reactor Coolant System (PWR), (ADAMS Accession No. ML070380222) Item 4 on page 15.4.6-8, states:
When necessary, the reviewer evaluates the effects of single active failures of systems and components that may affect the course of the transient. This phase of the review uses SRP system review procedures for SAR Chapters 5, 6, 7, 8, and 9. In particular, redundant alarms that alert the operator to the unplanned dilution are confirmed.
It is the NRC staffs understanding that the operator relies upon a neutron flux alarm to identify and terminate a design basis boron dilution event or to detect a misloaded assembly. Additionally, licensees use the neutron flux alarm to alert personnel working in the vicinity of the reactor of the high neutron flux condition (via local alarm and/or announcement) and to prevent possible offsite releases of radioactive material.
- b. During core alterations (i.e., movement of fuel), there is the potential for operable neutron detectors to become effectively decoupled from the fuel assemblies being monitored. For example, some plants have only two source range monitors (one for each half of the core).
If one source range monitor becomes inoperable, and certain, strategically located fuel assemblies are removed; then the other, operable neutron source monitor may no longer be capable of monitoring some fuel assemblies that are located in the far half of the core.
Therefore, the NRC staff is concerned that the removal of the words CORE ALTERATIONS from the TS LCO for source range monitors may create a situation where a boron dilution accident, misloaded fuel assembly, or an increase in neutron flux might go undetected. The NRC staffs preliminary review of this issue indicates that the removal of the words CORE ALERATIONS may create a situation not consistent with the SRP guidance related to redundant alarms, described in SRP Section 15.4.6.
- c. The NRC staff is concerned that a dropped source, fuel assembly, or component (or any other item allowed to be moved by CORE ALTERATIONS) could damage a fuel assembly or break creating a radioactive source term. Additionally, a dropped source, component, or fuel assembly could add reactivity if it is dropped over or in the vicinity of other fuel. If so, the NRC staff may require an analysis to show that the dose consequences of these scenarios are less limiting than the current fuel handling accident.
- d. The NRC staff is also concerned that if there is no definition of core alterations in the TS there may be some confusion as to the circumstances or operations under which the requirement of Title 10 of the Code of Federal Regulations Section (10 CFR) 50.54 applies. The regulation at 10 CFR 50.54 specifies the
TSTF assignment of a senior operator dedicated to fuel handling tasks during core alterations.
The issues identified above are preliminary. The NRC staff needs additional time to complete a thorough review. Therefore, it is suggested that licensees should not submit amendments to adopt these three Travelers until a final resolution is achieved. The NRC staff would consider working with the industry in getting the concerns resolved. Any further changes in acceptance or review of license amendments adopting these three Travelers will be communicated promptly.
If you have any questions please contact Michelle Honcharik of my staff at 301-415-1774 or Michelle.Honcharik@nrc.gov.
Sincerely,
/RA/
Anthony J. Mendiola, Chief Licensing Processes Branch Division of Policy and Rulemaking Office of Nuclear Reactor Regulation Project No. 753 cc: See next page
- concurred via e-mail NRR-106 OFFICE PLPB/PM PLPB/LA SRXB/BC*
AADB/ABC STSB/BC*
PLPB/BC NAME MHoncharik DBaxley CJackson JDozier RElliott AMendiola DATE 11/7/13 9/5/13 11/6/13 9/12/13 9/12/13 11/7/13
Technical Specifications Task Force Project No. 753 cc:
Technical Specifications Task Force 11921 Rockville Pike Suite 100 Rockville, MD 20852 Attention: Brian Mann E-mail: brian.mann@excelservices.com Robert A. Slough Comanche Peak Nuclear Power Plant P. O. Box 1002, Mail Code A08 Glen Rose, Texas 76043 E-mail: robert.slough@luminant.com Richard A. Loeffler Monticello Nuclear Generating Plant 2807 West County Road 75 Monticello, MN 55362-9637 E-mail: richard.loeffler@xenuclear.com Wendy E. Croft Exelon Nuclear 200 Exelon Way, Suite 340 Kennett Square, PA 19348 E-mail: wendi.croft@exeloncorp.com Otto W. Gustafson Entergy Nuclear Operations, Inc.
Palisades Nuclear Power Plant 27780 Blue Star Memorial Highway Covert, MI 49043 E-mail: ogustaf@entergy.com