ML20064K696
| ML20064K696 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Fort Calhoun |
| Issue date: | 04/02/1981 |
| From: | Sniezek J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Arlotto G, Eisenhut D Office of Nuclear Reactor Regulation, NRC OFFICE OF STANDARDS DEVELOPMENT |
| Shared Package | |
| ML082180535 | List:
|
| References | |
| FOIA-82-261 NUDOCS 8105040512 | |
| Download: ML20064K696 (3) | |
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.. Docket Ffles' IE Files WJCollins Rdg Files APR- -21981 IE Rdg Files RRRI Rdg Files Docket No. 50-235 REB Rdg Files MEMOP#iDGt FOR:
D. G. Eisenhut. Director Civision of Licensing. Office of Fiuclear Reactor Regulation G. A. Arlotto, Director, Division of Engineering Standards, Office of Standards Develo; ment FROM:
James H. Snferek, Director, Division of Resident and Regional Reactor Inspection IE
SUBJECT:
CORRCSION DAMAGE OF STUD-BOLTS AND PIPING AT PWR PLANTS In May 1980, Cuiaba Publfc Power District (OPPD) subsf ttad a spec 1al ma1ntenance report to the NRC concerning the significant corrosion wastage to the closure studs of the Reactor Coolant Pumps (RCP's) at their Fort Cahun facility.
The corrosion testage was attributed to boric acid attack as a result of laakage at flexitallic gasketed joints between the pump casing and pump cover (LER 80-010/07-0, June 1980). 4s a result of this incident, we issued Infermation Notice 80-27. June 11,1980 to all PWR licensees regarding the potential for undetected boric acid corrosion damage and emphasized the need for supple-mental visual inspection of pressure retaining bolting in pump and valve components. Consequenfly, sinflar occurrences of corrosion wastage dee to boric acid leakage haI been identiffed at other PWR plants. The plants and-
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components affected to data are provided in Enclosure 1.
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Fortunately, the licensees' timely visual inspections during refueltag outages in response to the Information Notice identified the gasket leakage and corrosion da: age, and none of the occurrences compromised the health and safoty of the
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public.
Th3 present ASHE Section XI Examination and Acceptance Requirements for~
Pressure-Retaining Bolts and Studs (Category 8-6-1) are primer 11y directed
' toward detection of crack-type indicat e.* s.
Expertence has clearly shown that volanetric NDE method (s)etre inadequate to detect the localtred corrosion wastage observed. In view of this and the generfc trend of such incidents, we believe that prompt action is necessary and practical to faplement.
l Two interrelated courses of action by J$50 and HRR are proposed:
1.
SCSD - the applicable AS?!E Section XI rules pertaining to examination of boltin2 s?muld be revised to include surface examination and eva1uation procedures for corrosion detection and assessment of low alloy carbon steel bolting in pressure-petatning components within PWR primary and i
l safegeerds systems. Ve envision these additional rules would include, as a minimum.
CONTACT:
W. J. Collins, IE
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A2J9 W &[ p 4g l
49-25100
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Hultiple Addressees 2
APR 2 1981 a.
Standards for visual exar.ination and evaluation, b.
Identified components and system categorfes for examination, tod-
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Systes pressure condttions for conducting the exastnation, and c.
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Examination frequency or minimum time interval (f.e.. every 3-1/3 years) between exaufnations.
2.
NRR - requireithat all PWR licensees augeent their present ISI plan to include, on an interia basis, surface examination procedures of such low alloy steel components at forthcoming refueling outages, and every other refueling outage thereafter, until the above proposed rules revision is incorporated into ASME Section II and, subsequently, plant ISI program requirements.
We propose a meeting to discuss the IE proposal and a schedule for actions at g:00 a.m. os April 9,1g81 in Room 319 of East-West Towers.
Should you have any questions regarding this matter, we will be glad to discuss them at your convenience.
James H. Snferek. Director Divisfon of Resident and Regional Reactor Inspection Office of Inspection and Enforcement
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Enclosure:
Listing of plants Affected by Boric Acid Corrosion i
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V. Stallo. IE l
R. DeYoung. IE Regfonal Ofrectors R. H. Yellmer. IE t
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l IE: REB IE: REB IE:RRRI:DD IE:RRRI:D WJCollins:mkr: RWoodruff ELJordan JHSnfezek
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INCIDENTS OF BORIC ACID CORROSION AT PWR PLANTS (MARCH 27,1981)
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PLANT COMPONENT REPLACEMENT REQUIRED Fort Calhoun RCP Studs 23 of 48 Calvert Cliffs 1 RCP Studs 27 of 64 St. Gen Manway Studs 11 of 40 Calvert Cliffs 2 RCP Studs 12 of 64 Pressurizer Manway Studs 2 of 20 SI Check Valve (2-SI-217) Studs 16 of 16 RCP-30" Suction Piping No Kewaunee Studs of In-Line Motor All Operated Valve to SI Pump Suction from BIT Oconee 2 RCP Studs -
Licensee Evaluation Incomplete Oconee 3 RCP Studs 1 of 64
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