ML20210B396

Discusses Results from Snubber Testing for Review of 860731 Application for Amends to Licenses DPR-53 & DPR-69 Re Snubber Insp Interval & Functional Test Requirements.Error in Tech Spec Numbering Noted

ML20210B396
Person / Time
Site:	Calvert Cliffs
Issue date:	02/03/1987
From:	Salyards L BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 8702090149
Download: ML20210B396 (4)

Text

. . I BALTIMORE GASAND ELECTRIC CHARLES CENTER . P.O. BOX 1475 BALTIMORE, MARYLAND 21203 NUCLEAR ENGINEERING SERVICES DEPARTMENT CALVERT CUFFS NUCLEAR POWER PLANT LUSBY, MARYLAND 20657 February 3,1987 U. S. Nuclear Regulatory Commission Washington, D. C. 20555 ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Request for Amendment, Additional Information

REFERENCES:

(a) Letter from Mr. 3. A. Tiernan (BG&E), to Mr. A. C. Thadani (NRC),

dated July 31,1986, Request for Amendment Gentlemen:

Reference (a), Change No.1, proposed to change the snubber inspection interval and functional test "18 month" requirements to " refueling interval." These changes are j necessary due to the fact that we are extending our refueling interval to 24 months.

Additionally, these changes are supported by our successful snubber program and minimal snubber failure rate. This letter provides the results of our recently completed snubber

testing for your use in the ongoing review of Reference (a), Change No.1. Also, an additional administrative change to the Technical Specifications is proposed.

Snubber Inspection Results

! The snubber inspection results from our most recent refueling outage (Unit 1, Fall 1986)

! were excellent. These results support our request in Reference (a) to lengthen our snubber inspection interval. Thirty-two small bore, and two large bore snubbers were functionally tested with no failures. Also, all safety related snubbers were visually I inspected. Again, no snubbers failed the acceptance criteria.

1 f

However, in December 1986, our Plant Operations and Safety Review Committee (POSRC) determined that a Unit 2 main steam line snubber was indeed inoperable (for the purpose of establishing the next snubber visual inspection period). On May 22,1986, snubber 2-83-16A was found with the piston rod disengaged from the rod eye. The snubber was declared inoperable and replaced with a new snubber. An investigation revealed that the rod eye became disengaged from the piston rod as a result of improper installation of the rod eye, combined with the relatively high vibration levels in the main steam line, inspection of the rod eye and piston rod indicated that no Loctite was applied during installation. POSRC determined that although improper installation was 00$O$17 - 00 l p)MlN Y PDR \

LQ

a Document Control Desk February 3,1987 Page 2 the most probable cause of snubber failure, there was insufficient evidence to determine that the lack of Loctite was the major contributor to failure. TI erefore, conservatively, this snubber failure will count as an inoperable snubber against Unit 2's Inaccessible Snubber Inspection during the upcoming outage in March 1987. This action will place Unit 2 on a 12 month visualinspection interval under the current Technical Specification requirements.

Additional snubbers along the main steam lines (on both units) were inspected to ensure all piston rod eyes were fully engaged. No problems were evident on the 58 additional snubbers inspected.

The failed snubber was installed during the Fall 1985 refueling outage. Approximately seven months later the snubber was found inoperable. Based on the short operating period of this snubber (realizing no Loctite was applied on installation), coupled with the overall excellent performance of the main steam line snubbers to date, this failure is considered an isolated occurrence.

Administrative Technical Specification Chanste

~

A review of our snubber Technical Specifications has revealed a minor error in Technical Specification numbering. Since these pages (Unit I and Unit 2; 3/4 7-25) are to be changed via Reference (a), this discrepancy can be corrected in conjunction with that license amendment submittal.

Although the snubber Limiting Condition for Operation and the Surveillance Require-ments are numbered 3.7.8.1 and 4.7.8.h respectively, the snubber Action Statement and Surveillance Requirement text specify 4.7.8.b, c, etc. We propose to match the latter numbering sequence by deleting the "1" (underlined above; also, see attached sample Technical Specification page).

Should you have any questions regarding either of the above topics, we will be pleased to discuss them with you.

Very truly yours,

' I,f e

L. E. Saiyards Principal Engineer Licensing Unit LES/BEH/ dim

Document Control Desk February 3,1987 Page 3 cc: D. A. Brune, Esquire J. E. Silberg, Esquire A. C. Thadani, NRC

. S. A. McNeil, NRC T. E. Murley, NRC T. Foley/D. A. Trimble T. Magette, DNR 1 i 4

8 6

i s

- - _ . . . . . - - - . . . . _ . _ . . - . . , . - _ . - _ . ~ - - - . . - , - . . _ - . _ - . . _ . _ . . . . , _ _ . . . _ . . - . - . - - . - . . - - - . - - _ _ , . , _ - . _ . - _ _ . . . _ , _ _ _-

PLANT SYSTEfE 3/4.7.8 SNUSBERS

-LIMITINS CONDITION x

FOR OPERATION I

3.7' 8 [ Al safety related snubbers shall be OPERABLE. I APP ILITY: 110 DES 1, 2, 3 and 4. (!10 DES 5 and 6 for snubbers located on systems required OPERABLE in those tiODES.

ACTION:

With one or more snubbers inoperable, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> replace or restore the inoperable snubber (s) to OPERABLE status, and perform an engineering evalua-tion

• per Specification 4.7.8.b and c on the supporting component or declare the supported system inoperable and follow the appropriate ACTION statement for that system.

SURVEII,1MCE REQUIREMENTS

4. 8// Ea 1 snubber shall be demonstrated OPERABLE by perfomance of the f llowing ugmented inservice inspection program and the requirements of S ecif' tion 4.0.5. As used in this Specification, type of snubber shall mean snubbers of the same design and manufacturer, irrespective,of capacity.

a. Visual inspections

( Visual inspections shall be performed in accordance with the following schedule:

No. Inoperable Snubbers of Subsequent Visual **

Each Type per Inspection Period Inspection Period #

0 18 months + 25%

1 12 months T 25%

2 6 months T 25%

3, 4 124 days + 25%

5,6,7 62 days T 25%

8 or more 31 days T 25%

The snubbers may be further categorized into two groups: Those accessible and those inaccessible during reactor operation. Each group may be inspected independently in accordance with the above schedule.

1 Safety related snubbers include those snubbers installed on safety related 7 systems and snubbers on non-safety related systems if their failure or the p failure of the system on which they are ins.talled would have an adverse ci effect on any safety related system.

A documented, visual inspection shall be sufficient to meet the requirements for an engineering evaluation. Additional analyses, as needed, shall be completed in a reasonable period of time.

• • The inspection interval shall not be lengthened more than two steps at a time.

1. The provisions of Specification 4.0.2 are not applicable.

CALVERT CLIFFS - UNIT 1 3/4 7-25 AmendmentNo.$A.JJB[

wn-A . . . _ ._ . . -