ML17334B462
| ML17334B462 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 02/23/1993 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Hoekstra P HOUSE OF REP. |
| Shared Package | |
| ML17334B463 | List: |
| References | |
| NUDOCS 9303030173 | |
| Download: ML17334B462 (9) | |
Text
~~i8 REGS~
~ (4
~o
+
~,4 Cy A.n 0 $
gO
+w*w+
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 February 23, j.993 The Honorable Pete Hoekstra United States House of Representatives Washington, D.C. 20515-2202 Dear Congressman Hoekstra:
I am responding to your letter of January ll, 1993, in which you enclosed correspondence from Ms. Joan Johnson. 's, Johnson expressed concerns about the deterior'ation of ",cooling tubes" at several nuclear power plants, particularly the Donald C.
Cook NucIear Plant in Benton Harbor, Michigan.
You asked about the accuracy, of the November 24, 1992, Associated Press (AP) article,referred to by Ms. Johnson.
This article addressed the integrity of steam generator tubes at the Trojan Nuclear Plant in Oregon, and the waiver that the Nuc'lear Regulatory Commission (NRC) granted from previously established.standards'for'-acceptability of these tubes.
The AP article deals with a'ompl'ex technical issue and extracts unrelated segments from internal NRC documents and therefore does not fully represent the agency's position on the matter.
The NRC staff has approved the use of interim revised standards for the integrity of steam generator tubes only for a certain type of defect.
These criteria have been applied to a small number of plants, they are currently rest'ricted to short-duration operations (typically one fuel-cycle of 12-18 months),
and compensating measures are required such as more restrictive limits on allowable leakage.
The NRC monitors steam generator operating experience and performs research to aid in evaluating this subject'. 'he documents referenced in the AP article were not final agency positions and reflected the staff's continuing discussions on a complex techqical issue.
While working to resolve generic technical 'issues such as the integrity of steam generator
- tubes, members of the NRC staff sometimes express differing opinions and analyses as a normal course of Agency business.
The NRC review'process includes peer and management review of varying. analyses and opinions to ensure that technical and safety issues are identified and resolved before requiring industry action.
You asked why the NRC standards for the integrity of steam generator tubes are being ignored or waived at several plants throughout the country.
The guidance contained in NRC Regulatory Guide (RG) 1. 121, "Bases for Plugging
'Degraded PWR Steam Generator Tubes,"
has generally led to the establishment of a 40 p'ercent through-wall "plugging limit" for flaws in steam generator tubes.
Such guides are generally cons'ervative since they apply to all plants.
It is 9'303030l73 930223 PDR ADOCK 05000315 H
PDR Qf 1$
VJ Qt F~
(0
I P
I 4i <<,n
.".SOOiO
The Honorable Pete Hoekstra February 23, 1993 common to have plant specific exceptions based on information applicable to that specific plant or circumstance.
Tubes removed from steam g'enerators at several plants contained numerous short axial, cracks that were greater than 40 percent through-wall, yet these tubes withstood pressures well above that which is required in RG 1. 121.
Research conducted by the NRC supports the contention that tubes can withstand high pressures
'even if the cracks are
- deep, as long as they are sufficiently short.
Upon considering evidence from examinations of tubes removed from service and extensive inspections-of tubes still in service, the NRC has approved interim tube plugging (IPC) criteria at several
- plants, including D.
C.
Cook Unit 1.
The interim criteria applied at these plants still require that tubes with unacceptable degradation be repaired or removed from service.
The NRC has imposed more extensive monitoring requirements for tube integrity and more conservative limits on tube leakage at those plants using IPC.
You also asked about the potential risk to Michigan residents.
We believe, based on our assessment of the D.
C.
Cook Unit 1 plant and the compensating measures taken, that there is not a significant risk to the public.
The NRC staff will continue to research and assess those issues pertinent to steam generator tube integrity.
I trust that this adequately responds to your constituent's concerns.
Sincerely, Original slgmd 4y dames M. Tayfor James H. Taylor Executive Director for Operations OFC LA:PD III-1 PH: PDI II-1 Tech Ed.
PD: PDI II-1 AD:DRPW HShuttleworth WDean JMain LHarsh JZwolinski DATE 02/03/93*
02/10/93*
02 02/93*
02 3 93*
02 4 93*
OFC BC:EMCB D:DRPW ADP NRR D:NRR EDO OCA NAME DATE JStrosnider JRoe 02 05 93*
02 05 93*
JPartlow 02 08 93*
THurley JTay or 02/11 93*
02/
93 DRathb n
02@>/93 Document Name:
WPDOCS(DCCOOK)HOEKSTRA.HEH
- See previous co currence
DISTRIBUTION:
Docket No. 50-315 w/incoming EDO ¹8495 NRC
& LPDRs EDO Reading JTaylor JSniezek JBlaha HThompson THurley/FHiraglia JPartlow WRussell TGody Sr.
DCrutchfield BDavis, RIII PDIII-1 RF w/incoming JRoe JZwolinski LHarsh OGC OPA OCA TGibbons SECY CRC-93-0039 NRR Mail Room(12/G/18)
(EDO ¹8495 w/incoming)
BClayton 12/G/18 WDean w/incoming HShuttleworth PDIII-1 Green Tckt File EGreenman, RIII JKnubel SHoffman EHurphy MMayfield GBurdick DRathbun WShafer RIII
I'
flECO
~
~ ~Cp
+
0 Cy
- 0O I
Cy r+
o~
Cp
++*++
t UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 EDO Principal Correspondence Control FROM:
Rep.
Pete Hoekstra TO:
Dennis Rathbun, OCA FOR SIGNATURE OF:
Executive Director DESC:
DUE: 02/02/93 GRN EDO CONTROL: 0008495 DOC DT: 01/11/93 FINAL REPLY:
CRC NO: 93-0039 ROUTING:
DATE: 01/21/93 ASSIGNED TO:
CONTACT:
ENCLOSES LETTER FROM JOAN T.
JOHNSON CONCERNING SAFETY OF NUCLEAR POWER PLANTS INCLUDING D.C.
COOK Taylor Sniezek Blaha Knubel
REPLY TO MUSKEGON, MI OFFICE.
~~~ ~'W r pi/p~
P/~& ~+a~: >Row/~~
Ag/ (Og OUETOttRRO cloR
~:-C 1 ggj QpFtnt-
J7 f
OFFICE OF THE SECRETARY CORRESPONDENCE CONTROL TICKET PAPER NUMBER:
CRC-93-0039 LOGGING DATE: Jan 19 93 ACTION OFFICE:
EDO AUTHOR:
AFFILIATION:
PETE HOEKSTRA U.S.
HOUSE OF REPRESENTATIVES ADDRESSEE:
LETTER DATE:
SUBJECT:
ACTION:
DENNIS RATHBUN Jan 11 93 FILE CODE: IDR-6 SAFETY HAZARDS REQ FOR INFOR PERTAINING TO THE SAFETY OF THE NUCLEAR POWER PLANT IN BENTON HARBOR Direct Reply DISTRIBUTION:
OCA TO ACK SPECIAL HANDLING: NONE CONSTITUENT:
NOTES:
DATE DUE:
SIGNATURE:
AFFILIATION:
JOAN JOHNSON Feb 3
93 DATE SIGNED:
Re."d Off. F00 O~~e Tiros
~
p gg0.008495 9
>> -a>( g 8-A-~