ML20150E401
| ML20150E401 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/28/1988 |
| From: | Tiernan J BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8803310247 | |
| Download: ML20150E401 (5) | |
Text
.
- e B ALTIMORE GAS AND ELECTRIC CHARLES CENTER P. O. BOX 1475 BALTIMORE, MARYLAND 21203 JostPH A.TIERN AN vier Parsiotut NycLtan Entnov March 28, 1988 U.
S.
Nuclear Rogulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos. 1 & 2; Docket Nos. 50-317 & 50-318 Request for Relief from ASME Code Section XI Recruirements Determined to be Impractical
REFERENCES:
(a) NRC Staff Guidance Letter on ASME Relief Requests dated November 24, 1976 (b) Updated Final Safety Analysis
- Report, Calvert Cliffs Nuclear Power Plant, Unit Nos.
1 r?.d 2,
Section 4.1.3.2, Steam Generator i
Gentlemen:
In accordance with 10 CFR 50. 55a (g) (6) (i),
we are requesting relief from an ASME Code Section XI requirement that has been j
determined to be impractical.
In accordance with Reference (a),
the information concerning this relief request is presented i
herein.
Performance of a hydrostatic pressure test on two welds of the Main Steam (MS) System of Unit 2 is impractical.
We request permission to defer the hydrostatic pressure test until the next J
regularly scheduled system hydrostatic test.
I.
Components for Which Relief is Reauested The attached drawing identifies the portion of the MS System for which hydrostatic pressure testing will be deferred to the next regularly scheduled system P l hydrostatic test.
This relief request will be applied to t
l p
the upstream pipe-to-valve welds for two six-inch check valves (2-MS-103 and 2-MS-106) which were replaced during g' \\h f 8803310247 890339 DR ADOCK 050oo337 DCD
Docum:nt Control Denk March 28, 1988 page 2 the current Unit 2 outage.
These valves are part of the Main Steam to AFW Pump Turbine System which was originally designed to B31.1 (1967) and are considered Class 3 for ISI purposes.
II.
M]iE Reauirement from Which Relief is Recuested ASME Code Section XI 1983 edition with Addenda through Summer 1983 paragraph IWA-4400 and IWA-4600 require that a hydrostatic pressure test be performed on t.
portion of pipe repaired or replaced.
For this Class 3
piping system, the hydrostatic test pressure is 1.25 times the design pressure (1000 psig) or 1250 psig, per IWD-5223 of ASME XI.
The test required on the portion of MS System described herein will be performed during the next regularly scheduled Steam Generator system hydrostatic pressure test.
III.
Easis for Relief During the current Unit 2 outage, 2-MS-103 and 2-MS-106 were replaced unexpectedly.
As shown on the attached drawing, these valves are located downstream of the steam supply valves (2-CV-4070 and 2-CV-4071) to the AFW pump turbines.
Although 2-CV-4070 and 2-CV-4071 were not designed to hold pressure in the reverse direction, they were successfully hydrostatically tested to 1100 psig during initial installation in 1982.
On March 26, 1988, we attempted to perform a hydrostatic test on the section of pipe in question by using 2-CV-4070 and 2-CV-4071 as boundary valves.
This test was unsuccess-ful.
The valves were gagged per vendor recommendation such that the valves would not be fully seated against back pressure, thereby preventing stem damage.
- However, test pressure could not be achieved because of excessive leakage.
Machining has been performed on internal components of 2-CV-4070 and 2-CV-4071 since original installation.
Although vendor recommended tolerances were maintained, they are now outside factory tolerances.
These changes are believed to have made the difference between accomplishing a back pressure test on initial installation and not being able to perform this now.
Therefore, the IWA-4400 requirement to perform a hydro-static test is deemed impractical, because it wculd subject the Steam Cenerators to full hydrostatic pressure.
i
Docurant Control Deck March 28, 1988 Page 3 The portion of piping (a total of 18 new welds) downstream of the check valves (2-MS-103 and 2-MS-106) was success-fully hydrostatically pressure tested March 26, 1988, and all the
- welds, including those for which relief is requested, were satisfactorily radiographed.
The IWA-4400 requirement to perform a hydrostatic pressure j
test upstream of 2-MS-103 and 2-MS-106 is impractical because that section of pipe cannot be isolated from the Steam Generators due to the inability of 2-CV-4070 and 2-CV-4071 to hold back pressure.
Hydrostatic testing would subject the Steam Generators to an unneces.cary pressure transient above its design pressure.,.
As explained in Reference (b), the operational lifetime of
?
the Steam Generators is limited by the number of times each is permitted to be hydrostatically pressure tested.
Therefore, the performance of this hydrostatic test would result in hardship without a compensating increase in the level of quality and safety.
IV.
Alternate Testina In lieu of a hydrostatic test, and in order to ensure a high level of quality and
- safety, the VT-2 visual examination for leakage will be conducted prior to or immediately upon return to service.
Radiographic examinations of all the full penetration butt welds have been completed satisfactorily.
A hydrostatic pressure test will be performed at the next regularly scheduled system hydrostatic test.
This relief is requested immediately, in order that the Unit Two start-up is not delayed.
The need for this request could not reasonably have been anticipated since the check valves were not originally planned for replacement and the inability to hydrostatically test against 2-CV-4070 and 2-CV-4071 was not anticipated given the success in 1982.
Pursuant to 10 CFR 170.21 we are including BG&E Check No. 1915861 to the NRC in the amount of $150.00 to cover the fee for this request.
---.p
Docum0nt Control Dack March 28, 1988 Page 4 l
Should have any questions regarding this request, we will be pleased to discuss them with you.
Very trul. y rs,
,/
. A. Tie na Vice Pre dent Nuclear nergy JAT/SRC/dlm Attachments cc:
D. A.
Brune, Esquire J. E.
Silberg, Esquire R. A. Capra, NRC S. A. McNeil, NRC W. T. Russell, NRC D.
C. Trimble, NRC i
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