ML19339B345
| ML19339B345 | |
| Person / Time | |
|---|---|
| Site: | Columbia, Washington Public Power Supply System, Satsop  |
| Issue date: | 10/10/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Ferguson R WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| References | |
| NUDOCS 8011060773 | |
| Download: ML19339B345 (1) | |
Text
tlc (9
o UNITED STATES 8
'h.
NUCLEAR REGULATORY COMMISSION
$f E
REGION V
&*[
o, 1990 N. CALIFORNIA BOULEVARD SUITE 202, WALNUT CREEK PLAZA 4me WALNUT CREEK, CALIFORNIA 94596 October 10, 1980 Docket Nos. 50-397, 50-460, 50-508, 50-509, 50-513 Washington Public Power Supply System P. O. Box 968 3000 George Washington Way Richland, Washington 99352 Attention: Mr. R. L. Ferguson Managing Director Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the infor-mation for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular or Bulletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, L2ms
(
pt R. H. Engelken Director
Enclosures:
1.
IE Information Notice No. 80-36 2.
List of Recently Issued IE Information Notices cc w/ enclosures:
M. E. Witherspoon W. C. Bibb
'J. P. Thomas D. E. Dobson G. C. Sorensen 8011060773 h
IT D 1FM arm L.)$ g g iJ8 SSItis fjo.:
6835 8
Accession flo.:
8006190085 Iti 80-36 UtlITED STATES flUCLEAR REGULATORY COMf1ISSI0tl OFFICE OF ItiSPECTI0tl AtlD EllFORCEMEtlT WASHIf!GT0fi, D.C.
20555 i
October 10, 1980 IE Information flotice flo. 80-36:
FAILURE OF STEAM GEtlERATOR SUPPORT BOLTIflG 4
Description of Circumstances:
On September 4,1980, the flRC staff was informed by the florthern States Power Company that extensive cracking of the bolting for the supports attached to i
bottom of the stean generators on Prairie Island Unit 1 had occurred. The licensee initially discovered the bolting problen when two bolts failed during detensioning. The licensee was attempting to remove the pre-load on the bolting (specified at 1400 ft-lbs) to minimize the potential for str,ess corrosion cracking of the high strength 1-1/2 in, dia. 250 ksi maraging steel bolting (Vascomax 250).
Ultrasonic examination of the support bolting revealed cracks or breaks in 47 of 48 support bolts for the two steam generators at the Prairie Island Unit 1 facility. The licensee subsequently shut down the Prairie Island Unit 2 facility and performed ultrasonic examinations of the same steam generator support bolting, that failed on Unit 1.
The results of the UT examinations-revealed cracks in three of the 48 steam generator support bolts. The licensee attempted to remove the cracked bolts from the steam generator supports. Two cracked bolts were successfully removed while the third failed during removal.
Two bolts that were judged as defect free by the ultrasonic examination were also removed. Magnetic particle examinations confirmed the results of the ultrasonic examinations on the bolts which were removed. As part of the short term corrective actions taken, the licensee has unloaded and retensioned the
]
bolting at approximately 50 to 100 ft.-lbs.
1 Inservice ultrasonic examination of the affected bolting had been performed previcusly.
In the case of Unit 1 a significant number of the bolts were examined at the last refueling outage 14 months ago.
fio cracks were found at i
that time.
i The susceptibility for stress corrosion cracking was identified in flVREG-0577
(.forcomment). The flVREG identifies those facilities which have utilized maraging steels for reactor coolant pump and steam generator support bolting.
Further the f!VREG recommends augmented inspections for the facilities included in Group I.
Licensees are encouraged to review the bolting materials used at their respective facilities and consider inspection of maraging steel bolting that are either pre-loaded or significantly loaded during operation.
This Information t!otice is provided as an early notification of a possibly significant matter that is still under review by the flRC staff.
It is expected that recipients will review the information for possible applicability to their facility.
flo. specific action or response is requested at this time.
If you have any questions regarding this matter, please contact the Director of the appropriate flRC Regional Office.
IN 80-36 October 10, 1980 RECENTLY ISSUED IE INFORMATION NOTICES Informa tion eate of Notice No.
Sub.iec t Issue Issued to 80-35 Leakina and dislodced 10/10/80 All categories G and Iodine-124 inplant seeds G1 redical licensees 80-34 Boron dilution of reactor 9/26/80 All pressurized water coolant during steam reactor facilities generator decontamination holding power reactor OLs 80-33 Ceternination of teletherany 9/15/80 All teletherapy tirer accuracy (G3) licensees 80-32 Clarification of certain 8/12/30 All NRC and agreement reauirements for Exclu-state licensees sive-use snipments of radieactive materials 80-31 Maloperation of Gould-8/27/30 All light water reactor Brown Boveri Type 480 facilities holding OLs volt tyre K-600S and or cps V,-DON 600S circui t breakers 80-30 Potential for unaccept-0/19/80 All boiling water reactor able interaction between facilities holding power the control rod drive scram reactor OLs or cps.
function and non-essential control air at certain GE Bilk facilities 80-29 Broken studs on Terry 8/7/80 All light water reactor turbine steam inlet facilities holding flanqe power reactor OLs or cps
- Supplement to "otification of 7/29/80 All holders of reactor 80-06 significant events at and near-term OL operatinq power reactor applicants facilities 80-28 Prompt reportino of 6/13/80 All applicants for and recuired information holders of nuclear power to NRC reactor cps 80-27 Degradation of reactor 6/11/80 All pressurized water coolant pump studs reactor facilities holding power reactor OLs or cps
- Operating Licenses or Construction Permits