ML20062K995
| ML20062K995 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 08/02/1982 |
| From: | William Jones OMAHA PUBLIC POWER DISTRICT |
| To: | Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| REF-SSINS-6820 IEB-82-02, IEB-82-2, LIC-82-269, NUDOCS 8208180089 | |
| Download: ML20062K995 (6) | |
Text
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a Omaha Public Power District 1623 HARNEY E OMAHA. NESRASMA 68102 m TELEPHONE 536 4000 AREA CODE 402 August 2, 1982 LIC-82-269 Mr. J. T. Collins, Administrator
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U. S. Nuclear Regulatory Commission q
Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 I; -
AUG 6 1982 b
Reference:
Docket No. 50-285
Dear Mr. Collins:
IE Bulletin 82-02 Degradation of Threaded Fasteners in the Reactor Coolant Pressure Boundary (RCPB) of PWR Plants Item 5 of the subject bulletin requested information related to closures in the Fort Calhoun Station's RCPB that have experienced leakage in the past or for which fastener lubricants or injection sealants have been used.
Omaha Public Power District's response is attached.
Sincerely, J
(ij'fd' W. C. Dones Division Manager Production Operations WCJ/TLP:jmm Attachment cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.
Washington, D.C.
20036 Mr. Lawrence A. Yandell - NRC Senior Resident Inspector
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8208180089 820802 PDR ADOCK 05000285 G
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
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Omaha Public Power District
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Docket No. 50-285 (Fort Calhoun Station,
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Unit No.1)
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..... being duly sworn, hereby deposes and says that he is Division Manager - Production Operations of Omaha Public Power District; that he is duly authorized to sign and file with the Nuclear Regulatory Com-mission the attached response to IE Bulletin 82-02; that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his kno edge, information and belief.
?f W. C. Jones Divis cin Manager Produc, tion Operations STATE OF NEBRASKA)
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Subscribed and sworn to before me, a Notary Public in and for the State of Nebraska on this
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day of August, 1982.
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v GENERAL NOIARY-State of Nebrask:
JERoME L. Wo2NY d e, y Mr Comm. Esp Me N,1984 j
o OMAHA PUBLIC POWER DISTRICT'S RESPONSE TO ITEM 5 0F IE BULLETIN 82-02 Request Identify those bolted closures of the RCPB that have experienced leak-age, particularly those locations where leakage occurred during the most recent plant operating cycle.
Describe the inspections made and cor-rective measures taken to eliminate the problem.
If the leakag. was attribeted to gasket failure or its design, so indicate.
District's Response In response to the above request, the Fort Calhoun Station Reactor Coolant Pressure Boundary was evaluated for evidence of past leakage problems.
Using the criteria described in the bulletin, the scope of items investigated was limited to the threaded fasteners (studs or bolts)in:
(1) steam generator and pressurizer manway closures, (2) valve bonnets and pump flange connections installed on lines having a nominal diameter of 6 inches or greater, and (3) control rod drive (CRD) flange and pressurizer heater connections that do not have seal welds to provide leak-tight integrity.
For the Fort Calheun Station, these enclosures include:
Reactor Vessel (CE) RC-1 Control element drive mechanisms (49 total)
Steam Generators (CE) RC-2A & 2B Primary Manways (2 each)
Secondary Manways (2 each)
Secondary Handholes (2 each)
Pressurizer (CE) Manway Cover NOTE:
Pressurizer heaters have a seal weld and thus are excluded.
Pressurizer Safety Relief Valves RC-141 and RC-142 Valves are 3" inlet with a 6" outlet, they are removed annually for offsite testing.
Flange bolts are ASTM A-193 Grade 87.
The valves are manufactured by Crosby and have ASTM A-193 Grade B7 Bonnet studs.
Reactor Coolant Pumps RC-3A, 3B, 3C, 3D Reactor Coolant Pumps (RCP's) are manufactured by Byron Jackson.
The RCP casinos are each held together with sixteen 3\\" closure studs fabricated from ASTM A-193 Grade B7 carbon steel.
The following check valves in safety injection loops lA,1B, 2A, and 2B located on line sizes at least 6" in diameter:
SI-194, SI-197, SI-200, SI-203, SI-207, SI-208, SI-211, SI-212, SI-215, SI-216, SI-219, SI-220.
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- These valves are welded in place and have four 3/4" ASTM A193-68 cover bolts.
Leakage has been observed in only three of the components described above:
the RCP's, CEDM's, and pressurizer manway.
The RCP closure studs experienced corrosion damage as a result of leakage past the pump casing 0-ring seals.
The RCP leakage problems were fully detailed in IE Information Notice 80-27, dated June 11, 1980, and the District's letter (LIC-82-022), dated January 28, 1982.
The Fort Calhoun Station CEDM's have a lower assembly seating surface which is seal welded and an upper assembly autoclave that is sealed using a spiral wound (flexitallic) gasket.
In 1973, a leak on CEDM-18's omega weld was identified, repaired, and rechecked. There has been no subsequent leakage on any omega welds.
However, the CEDM's have ex-perienced leakage at the autoclave seating surface (see attached sketch).
In all cases, the leakage was stopped by replacing the spiral wound (flexitallic) gasket and inspecting and/or replacing the holddown bolts. Maintenance records indicate the following gaskets have been replaced:
March 1976 CEDM-3, 27 August 1976 CEDM-29 October 1976 CEDM-7, 32, 35, 38 December 1976 CEDM-8, 21, 22, 24, 31 1976 Total 12 October 1977 CEDM-1, 8, 10, 12, 21, 27, 40 November 1977 CEDM-ll 1977 Total 8
November 1978 CEDM-37 December 1978 CEDM-2, 7, 9, ll, 17, 18, 19, 21, 22, 24, 26, 28, 36, 38, 41 1978 Total 16 February 1980 CEDM7 March 1980 CEDM-2, 13, 17, 18, 19, 20, 22, 25, 26, 32, 33, 38, 41 1980 Total 14 November 1981 CEDM-2, 7, 11, 13, 17, 18, 19, 21, 22, 24, 25, 26, 29, 31, 32, 33, 35, 38, 41 1981 Total 19
I During the November 1981 replacement of 19 CEDM gaskets, the sealing surface for the autoclave was roughed-up to improve the gasket seals.
During the scheduled January 1983 outage, the 19 flanges shall be ex-amined for evidence of further leakage.
It was also noted that a pressurizer manway leakage problem occurred on November 23, 1977 when attempting to return the system to operation after a scheduled outage.
The manway cover had been reinstalled im-properly and developed immediate leakage problems.
Upon removal and installation of a new gasket, the problem leakage was eliminated and the unit returned to operation.
Request Identify those closures and connections, if any, where fastener lubri-cants and injection sealant materials have been or are being used and report on plant experience with their application particularly any instances of SCC of fasteners.
Include types and composition of materials used.
District's Response Maintenance records indicate that injection sealant compounds have never been used on any of the RCPB enclosures within the scope of IE Bulletin 82-02 at the Fort Calhoun Station.
The Fort Calhoun Station approved maintenance procedures call for use of NEVERSIEZE Pure Nickel #65 on all threaded fasteners. To date, the District has experienced no problems related to use of the NEVERSIEZE lubricant.
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