United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9712240055

Coltec Industries                            Fairbanks Morse

                                             Engine Division

                                             701 White Avenue

                                             Beloit, WI 53511-5492


                                             FAX: 608/364-0382

                             INTERIM LETTER

                        Supplement No.: 97-002-01

To: Document Control Desk

          U.S. Nuclear Regulatory Commission

          Washington, DC. 20555

From: Coltec Industries-Fairbanks Morse Engine Division (FMED)

Date: 18 December 1997

Subject: Weldments on Opposed Piston and Coltec-Pielstick Emergency

Stand-By Diesel Gen-Set Lube-Oil and Jacket Water Piping Systems

This supplement to the Interim Letter dated 30 September 1997 is intended

to inform the U. S. Nuclear Regulatory Commission and the affected

nuclear utilities on the status of the root cause investigation and

corrective/preventive actions associated with the Coltec-FMED Part 21

File No.: 97-002.

The initial interim letter posed six (6) questions that formed the basis

of the root cause investigation.

Question 1: Is the weld design compliant with customer requirements?

Response: Customer contract requirements are currently under review by

our After-Market Parts Department.  Three (3) general categories apply

the affected customers: 1) non specific design/fabrication requirement,

thus Coltec-FMED standards apply, 2) ANSI B31.1, and 3) ASME III, Class

3.  Coltec-FMED will continue to review customer requirements as part of

the ongoing investigation.

Question 2: Are the subject welds compliant with FMED design


Response: Sections of Lube-Oil and Jacket Water piping were submitted to

Coltec-FMED by Florida Power Corp., Baltimore Gas Electric, Virginia

Power, and Carolina Power & Light.  Of the welds examined to date, most

do not have full penetration and therefore do not technically meet the FM

welding design requirements.  However, several welds examined do have

full penetration through some portion of the joint.

                              A division of Coltec Industries Inc

Question 3: If not, do the existing welds posses sufficient strength?

Response: An Engineering procedure is developed and approved; however,

weld strength is yet to be determined by testing joints by means of a

burst test (pressurizing the piping, including the weld joint, to a high

pressure to see if the weld breaks and at what pressure-strength level).

Materials and set-up are necessary for this test process; they are

currently being gathered and organized.

Question 4: What is the root cause of the identified condition?

Response: The most likely root cause of incomplete penetration is a lack

of adequate instruction to the welders or welding operators to assure

that proper welds were obtained.  This would include instruction on

preparation of the weld joint, weld gap requirements, and attention to

detail on the part of the welder to see that full penetration was

obtained.  Moreover, lack of proper instruction to inspectors regarding

inspection of the finished welds must also be included as part of the

root cause.  While some welds may be difficult to inspect directly, there

are sufficient methods available that allow welds either to be inspected

indirectly, or serially as the piping is assembled

Question 5: What corrective action, if any, should the customer take?

Response: Corrective action by the customer is dependent upon the burst

test results (ref. Question 3).  If weld joints are generally found

unacceptable, then the customer should replace the affected piping with

property welded pipe.  If; however, the present piping is generally found

strong enough as a result of satisfactory burst tests, no further action

is required.

Question 6: what preventive action is required by FMED?

Response: Design engineers should be instructed regarding proper design

and symbology of welds to best obtain full penetration, including design

details on drawings that outline weld joint preparation (taper of inside

diameters on standard fittings where weld joints include welding to thin

wall mechanical tube, etc).

Welders/weld operators must be instructed regarding requirements for full

penetration welding, including operator/welder qualification.  Proper

weld joint preparation must be emphasized.

Inspectors must be instructed regarding proper methods to ensure welds

are properly made to design requirements, including full penetration

without excessive weld material on the inside diameter of the pipe.

The above corrective actions should be extended to commercial fabrication

as well.

Results from the burst test should be available by the end of January

1998, at which time the review of customer contract requirements should

also be complete.  A final letter of notification should be available by

the end of February 1998.


Scott A. Fratianne

Sr.  Quality Assurance Engineer

Paul Danyluk

Vice President, Engineering

cc:  M. Armfield

     T. Gill

     B. Hall


Page Last Reviewed/Updated Monday, March 30, 2020