ML18219C408
| ML18219C408 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 11/30/1976 |
| From: | Dolan J American Electric Power Service Corp |
| To: | James Keppler NRC/IE, NRC/RGN-III |
| References | |
| IEB-76-002 IEC-76-006 | |
| Download: ML18219C408 (12) | |
Text
AMER]CAN ELECTMC PQWER Servi ce Corporati on 2 Broadu.ay, Zctc 2ork, F. Y. 10004 (2(2) 422.4800 JOJlhl' DOLAÃ Scnior Ezectttiocl tee President Engineering 4 Conttrttct."on November 30, 1976 Donald C. Cook Nuclear Plant Docket No. 50-315 and 50-316 DPR No.
58 and CPPR No.
61 U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region IXX 799 Roosevelt Road Glen Ellyn, Illinois 60136 Attention:
Nr. J.
G.
Ke ler Re ional Director Gentlemen:
With regard to our April 20, 1976 response letter to XE Bulletin No. 76-02 entitled "Relay Coil Failure GE Type HPA,
- HGA, HICK, HllD Relays, " we must request an extension of time for installation of the replacement relays.
P The relay inspections of Unit 1 and Unit 2 were completed by the dates stated in the above letter.
On July 14, 1976 an order was placed with General Electric Company for 330 replacement units to be used in Unit l.
On October 18, 1976 the first shipment of 150 units, which depleted all of General
~
Electric Company '
- stock, was received by the plant.
Since that time 90 units have been installed on Unit l.
The balance of the order for, Unit 1, as well as 207 replacement= units for Unit 2, is expected to be received on site during the first week in December
'1976.
Our Ãaliott,'8 200th Year
'j[g76 Our Company's 70th Year 6 l976
Mr. J.
G. Kep~ er
- 2 member 30, 1976 The original date for completion of relay replacement was stated as January 31, 1977 for both Units 1 and 2.
Due to delays in completion and shipment of our order from General Electric Company, we require an extension of 120 days
~ for installation of the relay replacement in Unit 1.
Completion of Unit 2 relay replacements will be accomplished before operation of that Unit.
Very truly yours, Z. I ohn E. Dolan Senior Executive Vice president Engineering 6 Construction JED:mam CC Dr G.
R.
P.
R.
R..
~ R; R.
E. Volgenau, Director I&E, U.S.N.R.C.
Charnoff C. Callen W. Ste)-etee Nalsh J. Vollen N. Jurgensen Bridgman S. Hunter
I
CENTRAt. Ff l@g UNITED STATES NUCLEAR REGULATORY COIVIMISSION IIEGION III 7SS AOOSEVCLT AOAO GLEN eLLYN, ILLINOIS G0137
~ov 88 >978 American Electric Power Service Corporation.
Indiana and Michigan Power Company ATTN:
Mr. John E. Dolan Executive Vice President Engineering and Construction 2 Broadway New York, N w York 10004 Docket No. 50-315 Gentlemen:
Circular No. 76-06 dated November 22,
- 1976, contained errors and should be replaced with the enclosed circular dated November 26, J.976.
Sincerely, James G. Keppler Regional Director
Enclosure:
XE,Circular No. 76-06 cc'/encl:
R. U. Jurgensen, Plant Superintendent Central Files es PDR Local PDR ELD Ronald Callen, Michigan Public Service Commission David Dismore Comey, Citizens for BetLer Environment'pI.UTIOy F76 191K Qo
e'jjl3 3~4~ i N'".~'nr.ts
~I November 26, 1976 IE Circular No. 76-06 STRESS CORROSION CRACKS IN STAGNANT, LOW PRESSURE STAINLESS PIPING CONTAINING BORIC ACID SOLUTION AT PWR's DESCRIPTION OF CIRCUMSTANCES:
I'uring the period November 7, 1974 to November 1, 1975, several incidents of through-wall cracking have occurred in the 10-inch, schedule 10 type 304 stainless steel piping of the Reactor 'Building Spray and Decay Heat
'Removal Systems at Arkansas Nuclear Plant-No. l.
n On October 7, 1976, Virginia Electric and Power also reported.through-wall cracking in the 10-inch schedule 40 type )04 stainless discharge piping of the "A" recirculation spray heat exchanger at Surry Unit No. 2.
A recent inspection of Unit 1 Containment Recirculation Spray Piping revealed cracking similar to Unit 2.
On October 8, 1976, another incident of similar cracking in 8-inch schedule 10 type 304 stainless piping of the Safety Injection Pump Suction Line at the Ginna facility was reported by the licensee.
Information received on the metallurgical analysis conducted to date indicates that the failures were the result of intergranular stress corrosion cracking that initiated on the inside of the piping.
A commonality of factors observed associated with the'corrosion mechanism were:
1.
The cracks were adjacent to and propagated along weld zones of the thin-walled low pressure piping, not part of the reactor coolant system.
2.
Cracking occurred in'iping containing relatively stagnant boric acid solution not required for normal operating conditions.
3.
Analysis of surface products at this time indicate a chloride ion interaction with oxide formation in the relatively stagnant boric acid solution as the probable corrodant, with the state of stress probably due to welding and/or fabrication.
The source of. the chloride ion is not definitely known.
However, at ANO-1 the chlorides and sulfide level observed in the surface tarnish film near welds is believed to have been introduced into the piping during testing of the sodium thiosulfate discharge valves, or valve leakage.
Similarly, at Ginna the chlorides and potential oxygen
a
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IE Circular No. 76-06 November 26, 1976 availability were assumed to have been present since original construction of the borated water storage tank which is vented to
'tmosphere.
Corrosion attack at Surry is attributed to in-leakage of chlorides through recirculation spray 'heat exchange tubing, allowing buildup of contaminated water in an otherwise normally dry spray piping.
ACTION TO BE TAKEN BY LICENSEE:
1.
Provide a description of your program for assuring continued integrity of those safety-related piping systems which. are not frequently flushed, or which contain nonflowing liquids.
This program should include consideration of hydrostatic testing in accordance with ASME Code Section XI rules (1974 Edition) for all active systems required for safety injection and containment spray, including their recirculation modes, from source of water supply up to the second isolation valve of the, primary system.
Similar tests should be considered for other safety-related piping systems'".
2.
Your program should also consider volumetric examination of a representative number of circumferential pipe welds by non-destructive examination techniques.
Such examinations should be performed generally in accordance with Appendix I of Section XI of the ASME Code, except that the examined area should cover a distance of approximately six (6) times the pipe wall thickness (but not less'han 2 inches and need not exceed 8 inches) on each side of the weld.
Supplementary examination techniques, such as radiography, should be used where necessary for evaluation or confirmation of ultrasonic indications resulting from such examination.
3.
A report describing your program and schedule for these inspec-tions should be submitted within 30 days after receipt of this Circular.
4.
The NPC Regional Office should be informed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, of any adverse findings resulting during nondestructive evaluation of the accessible piping welds identified above.
5.
A summary report of the examinations and evaluation of results should be submitted within 60 days from the date of completion
of proposed testing and examinations."
l II I
E 4
IE Circular No. 76-06 November 26, 1976 This summary report should also include a brief description of plant conditions, operating procedures or other activities which provide assurance that the effluent chemistry will maintain low levels of potential corrodants in such relatively stagnant regions within the piping.
Your responses should be submitted to the Director of this office, with a copy to the NRC Office of Inspection and Enforcement, Division of Reactor Inspection Programs, Washington, D.C.
20555.
Approval of NRC requirements for reports concerning possible generic problems has been obtained under 44 U.S.C 3152 from the U.S. General Accounting Office.
(GAO Approval B-180255 (R0062), expires 7/31/77.)
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