ML023500293
| ML023500293 | |
| Person / Time | |
|---|---|
| Site: | Boiling Water Reactor Owners Group |
| Issue date: | 12/16/2002 |
| From: | Holland D NRC/NRR/DLPM/LPD4 |
| To: | Ruland W NRC/NRR/DLPM |
| Holland D, NRR/DLPM, 415-1436 | |
| References | |
| Download: ML023500293 (6) | |
Text
December 16, 2002 MEMORANDUM TO: William H. Ruland, Director Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation FROM:
Drew Holland, Project Manager, Section 2
/RA/
Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF MEETING WITH THE BOILING WATER REACTOR OWNERS GROUP (BWROG) CONCERNING THE DEVELOPMENT OF A NEW REACTOR CORE STABILITY LIMIT On November 5, 2002, an open meeting was held between the BWROG and the NRC staff to discuss the BWROG efforts to develop a new reactor core stability limit. If developed, the new stability limit will provide the best basis for the final resolution of this issue with the class of boiling water reactors referred to as the "detect and suppress" (D&S) plants. In June 2001, GE Nuclear Energy reported that generic delta I versus oscillation magnitude (DIVOM) curves could be non-conservative. This resulted in a 10 CFR Part 21 notification. Individual plants implemented corrective actions as a result and the BWROG D&S Committee was reformed to develop a new generic DIVOM correlation.
The committee considered several alternatives and selected an approach that uses the TRACG computer program to calculate a best estimate critical power ratio response to oscillations and initiating events. In addition, the alternative would establish a generic setpoint that would provide safety limit minimum critical power ratio protection. The new stability limit will no longer be based on the maximum critical power ratio.
The BWROG stated that requirements for the new limit include:
satisfying regulatory requirements,
satisfying fuel design limits for stability,
allowing a return to operation immediately after a stability event and not requiring additional evaluations,
applicability to all BWR fuel vendors,
compatibility with existing stability based hardware/software,
maintenance of stability scram setpoints near current values, and
a limitation on oscillation magnitude and duration such that there is no predicted fuel rod failure and negligible change in fuel rod properties from those assumed in design and licensing analyses.
W. Ruland The presenters explained that the regulatory criteria being applied to this effort includes General Design Criterion 12, "Suppression of Reactor Power Oscillations" and Standard Review Plan (SRP) Section 4.2, "Fuel System Design." The new stability limit approach allows oscillations of limited magnitude and duration. In this way, fuel rods can go into and out of boiling transition. Also, sustained boiling transition will be avoided and clad temperature increase will be limited. The project will confirm that applicable fuel design limits are satisfied with the new stability limit. Based on feasibility study results, the design limits selected include:
cladding and channel stress and strain pertaining to creep deformations, annealing of irradiation hardening and pellet/cladding mechanical interaction,
cladding fatigue,
cladding oxidation,
dimensional changes including fuel rod growth and cladding collapse,
increased fission gas release and fuel rod internal pressure, and
fuel centerline melting.
These design limits establish all detailed fuel evaluations for stability.
In concluding, the BWROG stated that SRP Section 4.2 is the basis for stability design limits to protect the fuel. These design limits have been used in a feasibility study where annealing of fuel irradiation hardening has been identified as the most limiting requirement. This requirement can be met by limiting the peak cladding temperature and the duration of the instability event. The peak cladding temperature in turn is limited by the oscillation magnitude.
Proper selection of the stability scram setpoint will control the oscillation magnitude. The feasibility study utilized the TRACG computer code. Based on preliminary results, the fuel rods are not predicted to fail and there are negligible changes to fuel rod properties.
The staff thanked the BWROG for the presentation and encouraged an update on developments in the next several months. The staff expressed that this would be an ambitious undertaking. This meeting was informational. No regulatory decisions were made. The meeting handouts can be found in ADAMS under Accession No. ML023450532.
Project No. 691
Attachment:
Meeting Attendees cc w/att: See next page
ML023500293 NRC-001 OFFICE PDIV-2/PM SRXB*
PDIV-2/LA PDIV-2/SC NAME DHolland RCaruso EPeyton SDembek DATE 12/12/2002 12/10/2002 12/12/2002 12/13/2002 DOCUMENT NAME: C:\\ORPCheckout\\FileNET\\ML023500293.wpd
MEETING WITH THE BOILING WATER REACTORS OWNERS GROUP DEVELOPMENT OF A NEW REACTOR CORE STABILITY LIMIT NOVEMBER 5, 2002 GE NUCLEAR ENERGY R. Engel J. Andersen R. Hill D. Newkirk I. Nir WESTINGHOUSE ELECTRIC COMPANY U. Benjaminson W. Harris FRAMATOME D. Pruitt OTHER J. March-Leuba, Oak Ridge National Laboratory J. A. Gray, Entergy M. LeFrancoi, Energy Northeast T. Dresser, CP&L/Progress Energy J. D. Fisher, Energy Northwest W. Mertz, Southern Company M. May, Exelon R. Ramavarapu, Nuclear Management Company S. Pang, PSE&G S. Bier, PSE&G NRC J. Wermiel R. Caruso D. Holland S. Lu G. Thomas Z. Abdullahi A. Attard E. Kendrick T. Huang
BWR Owners Group Project No. 691 cc:
Mr. Kenneth Putnam, Vice Chairman BWR Owners Group Nuclear Management Company Duane Arnold Energy Center 3277 DAEC Rd.
Palo, IA 52324 Mr. James M. Kenny Reactor Response Group Chairman BWR Owners Group PPL Susquehanna, LLC Two North Ninth Street M/C GENA6-1 Allentown, PA 18101-1179 Mr. H. Lewis Sumner Southern Nuclear Company 40 Inverness Center Parkway P.O. Box 1295 Birmingham, AL 35242 Mr. Carl D. Terry Vice President, Nuclear Engineering Niagara Mohawk Power Corporation Nine Mile Point - Station OPS Bldg/2nd Floor P.O. Box 63 Lycoming, NY 13093 Mr. Thomas G. Hurst GE Nuclear Energy M/C 782 175 Curtner Avenue San Jose, CA 95125 Mr. Thomas A. Green GE Nuclear Energy M/C 782 175 Curtner Avenue San Jose, CA 95125 Mr. William H. Bolke Exelon 1400 Opus Place, Suite 400 Downers Grove, IL 60515 Mr. William A. Eaton ENTERGY Grand Gulf Nuclear Station P.O. Box 756 Port Gibson, MS 39150 Mr. Mark Bezilla PSEG NUCLEAR Hope Creek Generating Station P.O. Box 236 M/C H07 Hancocks Bridge, NJ 08038 Mr. James F. Klapproth GE Nuclear Energy M/C 706 175 Curtner Avenue San Jose, CA 95125