ML15238B170
| ML15238B170 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Oconee, Arkansas Nuclear, Crystal River, Rancho Seco, Crane  |
| Issue date: | 07/01/1980 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | Parker W DUKE POWER CO. |
| References | |
| NUDOCS 8007210004 | |
| Download: ML15238B170 (6) | |
Text
t JULY NS CIL OY 00,0H-CP IC NRR Rdg IE-4 NRC PDR TERA-3 DEisenhut ACRs-16 L PDR ORB#4 Rdg RPurple OELD Dockets Nos.,56-269, 50-270 RTedesco AEOD and 50-287 JO1shinski Gray File RReid MFairtile RIngram Mr. William 0. Parker, Jr.
TNovak Vice President,. Steam Production Duke Power Company P. 0.
Box 2178 422 South Church Street Charlotte, North Carolina 28242.
Dear Mr. Parker:
Recently we have been notified by the Toledo Edison Company that a number of fuel assembly holddown spring failures have been observed at the Davis Besse, Unit No. 1 plant which is currently undergoing its first refueling outage. We understand that as a result of these failures, Babcock & Wilcox has requested that you conductexaminations of fuel,assemblies at your facility to determine if any failures have occurred.
We are interested in knowing the results of holddown springinspections at your facility as well as the safety significance of operating with broken springs in the core.
Enclosed is a set of questions regarding this subject. It is requested that you provide responses to these questions within 60 days of receipt of this letter.
Sincerely, Original signed by Thomas M. Novak, Assistant Director
'for Operating Reactors Division of Licensing
Enclosure:
Holddown Spring Questions cc.w/enclosure:
See next page 800?2 10 001 *See.previous yellow for concurrences OFFICE ORB#4:DL*
C-ORB#4:DL AD-OR:DL SURNAME MFairtile/cb RReid*
Novak*
DATE 0./ 80.......
./1/80 7/1/80 NAC FORM 318 (9-76) NRCM 0240 U.S. GOVERNMENT PRINTING OFFICE: 1979-289-369
DISTRIBUTION:
Docket File-3 TERA-3 NRR Rdg NRC PDR NSIC DEisenhut L PDR ORB#4 Rdg RPurple
-RTedesco Dockets Nos. 50-269, 50-270 JOlshinski and 50-287 RReild MFairtile RIngram IE-4 Mr. William 0. Parker, Jr.
ACRS-16 Vice President, Steam Production OELD Duke Power Company AEOD P. 0. Box 2178 Gray File 422 South Church Street Charlotte, North Carolina 28242
Dear Mr. Parker:
Recently we have been notified by the Toledo Edison Company that a number of fuel assembly holddown spring failures have been observed at the Davis Besse, Unit No. 1 plant which is currently undergoing its first refueling outage. We understand that as a result of these failures, Babcock & Wilcox has requested that you conduct examinations of fuel assemblies at your facility to determine if any failures have occurrred. We are interested in knowing the results of holddown-spring inspections at your facility as well as the safety significance of operating with broken springs in the core.
Enclosed is a set of questions regarding this subject. It is requested that you provide responses to these questions within 60 days of receipt of this letter.
Sincerely, Thomas M. Novak, Assistant Director for Operating Reactors Division of Licensing
Enclosure:
Holddown Spring Questions cc w/enclosure:
See next page 8007210 00 OPB#4:DL fRf4yD ODL T O F F IC E
- b.
MEairtile/cb
- e.
SURNA M E~i O~
/8..................
/
8....................
6/T /80 6
/80 6/
/80 DATE
- U..
G N
I NRtC FORM 318 (9-76) NRCM 0240 U.S. GOVERNMENT PRINTING OFFICE: 1979-289-369
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 July 1, 1980 Dockets Nos.. 50-269, 50-270 and 50-287
- Mr. William 0. Parker, Jr.
Vice President, Steam Production Duke Power Company P. 0. Box 2178 422 South Church Street Charlotte, North Carolina 28242
Dear Mr. Parker:
Recently we have been notified by the Toledo Edison Company that a number of fuel assembly holddown spring failures have been observed at the Davis Besse, Unit No. I plant which is currently undergoing its first refueling outage. We understand that as a result of these failures, Babcock & Wilcox has requested that you conduct examinations of fuel assemblies at your facility to determine if any failures have occurred. We are interested in knowing the results of holddown spring inspections at your facility as well as the safety significance of operating with broken springs in the core.
Enclosed is a set of questions regarding this subject. It is requested that you provide responses to these questions within 60 days of receipt of this letter.
Sincerely, Thomas M. Novak, Assistant Director for Operating Reactors Division of Licensing
Enclosure:
Holddown Spring Questions cc w/enclosure:
See next page 8007210 (00~
Duke Power Company cc w/enclosure(s):
Mr. William L. Porter Mr. Robert B. Borsum Duke Power Company Babcock & Wilcox P. 0. Box 2178 Nuclear Power Generation Division 422 South Church Street Suite 420, 7735 Old Georgeton Road Charlotte, North Carolina 28242 Bethesda, Maryland 20014 Oconee Public Library Manager, LIS 201 South Spring Street NUS Corporation Walhalla, South Carolina 29691 2536 Countryside Boulevard Clearwater, Florida 33515 Honorable James M. Phinney County Supervisor of Oconee County J. Michael McGarry, III, Esq.
Walhalla, South Carolina 29621 DeBevoise & Liberman 1200 17th Street, N.W.
Washington, 0. C. 20036 Director, Technical Assessment Division Office of Radiation Programs (AW-459)
U. S. Environmental Protection Agency Office of Intergovernmental Aelations Crystal Mall #2 116 West Jones Street Arlington, Virginia 20460 Raleigh, North Carolina 273 U. S. Environmental Protection Agency Region IV Office ATTN:
EIS COORDINATOR 345 Courtland Street, N.E.
Atlanta, Georgia 30308 Mr. Francis Jape U. S. Nuclear Regulatory Commission P. 0. Box 7 Seneca, South Carolina 29678
Enclosure HOLD-DOWN SPRING QUESTIONS TO LICENSEES
- 1. (If the reactor is down for refueling and the reactor vessel head is off) Examine all fuel assembly holddown springs in the core and in the spent fuel pool and report the number and extent'of damage on the springs and affected assembly components.
or (Alt.) (If the reactor is operating.) Review video tapes of the core from the last refueling and examine all assemblies in the spent fuel pools.
Report the number and extent of damage on the springs and affected assembly components.
- 2. Provide a discussion of the safety significance of operating with one or more broken springs in the core. Your discussion should include, but not necessarily be limited to the following:
- a. Assume the holddown spring is broken, provide an estimate of the flow conditions under which the assemblies would be levitated. (Provide the value of the force required to lift the assembly, the flow conditions under which that force would be supplied, the number of coolant pumps that would be in operation under such conditions, and the schedule of reactor operations under which such conditions might have been achieved.) Contrarily, demonstrate the margin between the assembly weight and the calculated maximum applied lift-off force, if there is such margin.
- b. Have any loose assembly parts (i.e., broken springs, pieces of cladding) been observed anywhere in the primary system?
Describe your methods for loose part detection. Are there installed noise detectors capable of detection of broken springs, pieces of cladding, or vibrating assemblies?
- c. Have there been any excore or in-core neutron detector indications of levitated assemblies? Describe the expected reactivity effects that would result from lift-off or reseating of assemblies with broken hold-down springs. What efforts are being utilized to detect loose assemblies by either nuclear or mechanical monitoring devices?
- d. Have there been any observed indications of lateral repositioning of loose assemblies?. Describe the methods used to detect lateral assembly motion.
Describe the degree of lateral repositioning that is physically (dimensionally) possible after lift-off. What are the postulated worst-case effects of a laterally displaced assembly?
- e. (i) Describe the degree of "worst-case" mechanical damage that would be expected as a result of movement of a "loose" assembly (one with a broken spring) against adjacent assemblies, core baffle, or other core components.
Discuss the results of flow tests or other experiments that have provided measurements of axial or lateral vibratory motion of an assembly after lift-off or that would otherwise support the response to Q 2.e(i).
Enclosure
- 3. Provide a 'description of the cause of the failures and corrective action to reduce the likelihood of future failures at your facility.