ML20149E403

Interim Deficiency Rept CP-87-61 Re Snug Tight Torquing of Structural Bolts.Initially Reported on 870821.Spec 2323-SS-16B Revised to Require High Strength Bolts to Be Torqued.Next Rept Will Be Submitted by 880307

ML20149E403
Person / Time
Site:	Comanche Peak
Issue date:	01/05/1988
From:	Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
CP-87-61, TXX-88015, NUDOCS 8801130330
Download: ML20149E403 (2)

Text

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-- Log # TXX-88015 L 2 File # 10110 E E 903.8 7UELECTRIC Ref. # 10CFR50.55(e)

January 5, 1988 Elliam G. Counsil Emvene Vav Presakat U. S. Nuclear Regulatory Comission Attn: Document Control Desk Washington, D. C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) '

DOCKET N05. 50-445 AND 50-446 "SNUG TIGHT" TORQUING 0F STRUCTURAL BOLTS SDAR: CP-87-61 (INTERIM REPORT)

Gentlemen:

On August 21, 1987, we verbally notified your Mr. H. S. Phillips of a deficiency involving bolts utilized in structural connections which may not be torqued as required. We have expanded the scope of this issue to include the portion of SDAR CP-87-67 dealing with missing jam nuts. We have concluded that these issues are reportable under the provisions of 10CFR50.55(e). The required information follows.

Description 1his deficiency (inadequate torquing) was discovered during third-party '

investigations addressed in Corrective Action Request (CAR) 87-11.

FSAR Section 3.8 states that structural connections will conform to the requirements of the AISC specification contained in the 7th Edition of the Steel Construction Manual. These requirements specify that all high strength bolts to be torqued to a specified pretension. Contrary to this statement, Construction Procedure CCP-22, "Structural Steel Erection," Revision 3 (issued March 2, 1982) and Inspection Procedure QI-QP-ll.14-1, "Inspection of Site Fabrication an Installation of Structural and Miscellaneous Steel," Revision 6 (issuedJune 15,1982) were issued allowing high strength bolts in bearing ,

connections to be installed only snug tight. Design Change Authorization (DCA) 18853 Revision 0 was issued October 3,1983, revising Structural Specification 2323-SS-16, "Structural Steel / Miscellaneous Steel (Category I & I II)," also allowing high strength bolts in bearing connections to be installed only snug tight. Snug tight is defined as the tightness attained by a few impacts on an impact wrench or the full effort of a man using an ordinary spud wrench.

A subsequent review of inspection records (dated after the above document  !

revisions) for high strength bolted connections has revealed that some records indicate the torque obtained for each bolt while other records do not indicate  !

torque verification. l l

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' TXX-88015 January 5, 1988 Page 2 of 2 Regarding the second issue, DCA 18853 was revised to require jam nuts to be installed on all high strength bolts greater than or equal to 1 inch in diameter in bearing connections. Nonconformance Report (HCR) M86-102057X was subsequently issued to document missing jam nuts on high strength bolts on the Unit I rotating platform.

The deficiency involving bolt torquing was caused by the failure of the design organization to maintain procedure and specification requirements in compliance with FSAR commitments. The deficiency involving missing jam nuts was caused by the failure of the responsible craft to implement revised installation requirements to previously installed connections when the specification requirements were revised.

The implications of these deficiencies extend to all high strength bolts in bearing connections. The missing jam nuts have an additional implication of failure to implement backfit requirements resulting from a generic change to a design document.

Safety Implications Missing jam nuts and insufficient torque for high strength bolts in safety related bearing connections could result in the failure of ther,e connections to perform as required under seismic loading conditions.

These issues represent a significant construction deficier.cv which will require extensive evaluation to establish the adequacy of the associated structures, systems and components to perform their intended safety function.

Corrective _ Action Specification 2323-55-168 has been revised to eliminate the requirements for jam nuts and to require high strength bolts to be torquad to a specified pretension unless otherwise specified on the design documents. Field Verification Method (FVM) CPE-SWEC-FVM-EE/ME/IC/CS-090 has been issued to control the validation of existing installations. Connections for which the torque cannot be verified will be documented and dispositioned using NCRs.

Corrective actions for Unit 1 & 2 are currently scheduled. A follow-up report providing this schedule will be submitted no later than March 7,1988.

Very truly yours,

~, W W. G. Counsil CBC/grr c - Mr. R. D. Martin, Region IV Resident inspectors, CPSES (3)