United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9812030065

DuBose National Energy Services, Inc

November 30 1998

U S Nuclear Regulatory Commision
Document Control Desk
Washington, DC

Subject: Potential Part 21


This letter is to notify you of a potential Part 21 on material shipped to Niagara Mohawk, for unit #2. The material was 1" stainless steel SA 312 type 304 Schedule 40 pipe. Attached is a deviation / event report from Niagara Mohawk describing the situation on the material. Dubose has not supplied any of the material to any other customers.

As indicated in the attached report DuBose and Niagara have performed an investigation of the non compliance. The corrective action is that any material of this type supplied to Niagara Mohawk will be inspected by UT testing each length of material prior to shipping to Niagara.


James N. Daily
Manager, Quality Assurance

(910) 590-2151 1-800-590-2150 FAX (910) 590-3555
P.O. BOX [Illegible]

11/30/1998 U.S. Nuclear Regulatory Commission Operations
Center Event Report
Page 1
General Information or Other (PAR) Event# 35093
Rep Org: DuBOSE NATIONAL ENERGY SERVICES, IN Notification Date/Time: 11/30/1998
13:03 (EST)
Supplier: DuBOSE NATIONAL ENERGY SERVICES, IN Event Date/Time: 11/30/1998 (EST)
Last Modification: 11/30/1998
Region: 2 Docket #:
City: CLINTON Agreement State: Yes
County: License #:
State: NC Notifications: EDWARD MCALPINE R2
Emergency Class: NON EMERGENCY

A potential Part 21 on material shipped to Niagara Mohawk for Unit #2 (Nine Mile Point) was discovered by Niagara Mohawk and reported to the manufacturer. The material was 1 inch stainless steel SA 312 type 304 Schedule 40 pipe. Investigation determined that part of a shipment of about 600 feet did not meet minimum wall thickness. At the time of discovery, 80 feet had been installed in a system that was not operational. The balance of the pipe has been returned to the manufacturer and testing determined three minimum wall thickness violations. The minimum wall thickness violations will be addressed by Niagara Mohawk Design Engineering Department. The manufacturer has determined the apparent cause as "fabrication deficiency" and replaced the pipe.


PART 1 - IDENTIFICATION (Originator/Supervisor Page 1 of 5

A. Deviation/Event
Pipe Does Not Meet Manufactures Minimum Wall Specification Requirements
B. Event Date/Time (24 hr.) 9/3/98 1300
C. Applies to: Unit 1 Unit 2 Common 2-GTS-001-62-3, 2-GTS-001-63-3
D. Component I D (MEL) N/A
E. System N/A GTS
F. Location (Bldg/Elev/Area) N/A G. Identified By
Standby Gas Treatment Building NMPC NRC INPO OE Other
Elevation 261
H. Description of Deviation/Event
Seventeen feet of 1" stainless steel SA312 tp 304, schedule 40, pipe does not meet the manufactures minimum wall thickness specification requirements. Manufactures minimum wall thickness is 0.116", contrary to this, measurements as low as 0.097" have been recorded. The pieces were cut from a random length of pipe approximately 21 feet long. 600 feet of pipe was purchased safety related under Purchase Order 97-16100 from Dubose, to support the GTS actuator replacement, Design Change N2-97-048. The pipe stock symbol # 91-16-669, heat # 440506 was manufactured by Sandvick. Currently approximately 80 feet of the pipe is installed risk in the field in accordance with WO# 97-14211-03, The design change is not complete, the system is not operational. Although the pipe installeds wall thickness can not he verified visually, skills of the trade can reasonably ensure that the thickness meets specification. Pipe out of tolerance is visually obvious, thus questioned, then measured as in this case.
Maintenance requests the purchasing department Investigate the manufactures error (potential part 21 impact), and the suitability of the installed and remaining stock pipe. The design change is an NCTS commitment item, time is of the essence, the pipe must be installed and tested by Nov 13, 1998. 600 feet of 1" pipe is much more than whats needed to complete the design change.

Part of the Forms omitted.

Attachment "DER DISPOSITION Form" omitted.

Note Section To Which Additional Information Applies. Page 3 of


Purchase Order 97-16100 required the pipe to be supplied in accordance with ASME B&PV Code section III 1974 edition or the 1971 edition with the summer 1997 addenda subsection NC Class 2.

Dubose supplied 643 feet 2 inches of 1 inch stainless steel pipe heat number 440506 manufactured by Sandvik certified to the requirements of 1977 edition through the summer 1977 addenda.

The nominal wall thickness imposed by ASME Section III for 1 inch schedule 40 pipe is 0.133 inches. The dimensional tolerance applied by ASME Section III to the pipe wall thickness is 12.5 per cent. The 12.5 per cent tolerance of the nominal pipe wall thickness allows a minimum wall thickness for 1 inch schedule 40 pipe to be 0.116 inches with a maximum of 0.150 inches. This pipe was issued to the field on Risk Release DDC 2M11435 for Unit 2 modification N2-97-048. During the fabrication of Various spool pieces by the NMPC Mechanical Maintenance Shop it was visually noticed that some of the 1 inch pipe from heat number 440506 appeared to have a thin wall. Subsequently, an ultrasonic wall thickness test confirmed this. Approximately 80 feet of the pipe has been installed in Unit 2 as part of modification N2-97-048, but not declared operational. The remainder of the pipe is either in the Unit 2 Mechanical Maintenance shop or in storage.

Investigation of this issue with the Quality Assurance Manager of Dubose National Energy and Sandvik Inc., determined a similar problem occurred in 1997 with Sandvik steel manufactured 3/4" stainless steel pipe heat number 469899, which resulted in a 10 CFR 21 Report. The corrective actions for this issue included:

1. All the spool pieces in stock at Dubose were ultrasonically tested by Dubose to confirm the pipe's wall thickness. All spools not conforming to the wall thickness requirements were returned to Sandvik.
2. The Dubose Inspection Procedure was revised to require 4 ultrasonic test readings to be taken at one location on a random selection of the pipe spools 90 degrees apart at each test location.

Sandvik feels this inspection methodology adequately increases the probability of identifying a wall thickness problem because if the pipe drawing equipment is incorrectly aligned the whole spool length will be affected.

This Corrective action was implemented prior to the NMPC Purchase Order 97-16100.


Note Section To Which Additional Information Applies. Page 4 of

Sandvik Inc, reviewed the remaining pipe stock and discussed the problem with its customers. The conclusion of the Sandvik investigation concluded "no systematic problem exists". Therefore, Sandvik did not revise its inspection methodology or acceptance criteria.


The apparent cause was "fabrication deficiency." The manufacturer of the pipe, Sandvik Inc. Incorrectly manufactured the pipe. (002/N2a/PESA)



All the pipe in question was supplied from heat number 440506. This heat number has not been supplied to NMPC in the past. The pipe spool pieces fabricated from this heat number in the NMPC Mechanical Maintenance Shop have been ultrasonically tested as referenced on NMPC NDE report numbers 2-6.05-08-0031 and 2-6.05-08-0032, to determine whether the pipe wall thickness meets the ASME requirements. Those UT Reports concluded the statement by Sandvik that if the pipe spool is noted to have the correct wall thickness at the end of the spool the middle of the spool will have the correct wall thickness was incorrect. Therefore, the sampling methodology for the UT testing consists of ultrasonically testing each full spool piece at the ends and at each 5 foot intervals. Each cut spool piece less than 5 feet long was ultrasonically tested at one random location. Each spool piece greater than 5 feet was ultrasonically tested at one end and at each 5 foot intervals from the end. Four readings were taken at each test location 90 degrees apart for all the spools.

This sampling methodology was derived by discussions with the Quality Assurance Departments of the manufacturer, supplier, and NMPC, NMPC Design Engineering, NMPC Mechanical Maintenance Department and NMPC Procurement Engineering,

All non installed pipe associated with P.O. 97-16100 not meeting the wall thickness requirement has been scrapped.

The pipe not issued to the field has been returned to Dubose National Energy, the original pipe supplier for credit.

Replacement pipe purchased on P.O. 98-20362, was manufactured by Sandvik. All the pipe on Purchase Order 98-20362 was ultrasonically toned by the supplier prior to shipment and found to have acceptable wall thickness


Note Section To Which Additional Information Applies. Page 4 of

The 80 feet of pipe installed in the field has been ultrasonically tested by NMPC and found to have three minimum wall thickness violations. Reference NDE Report 2-6.05-98-0033. These minimum wall violations will be addressed by NMPC Design Engineering Department in calculation PX-78012-00A.

Completion date: 12/18/98


1. A comment will be added to all the NMPC QSL quelled pipe suppliers to consider an ultrasonic wall thickness test of the pipe being purchased.
Completion date, 10/30/99
2. A source surveillance will be performed of Sandvik Inc. by the NMPC Procurement Quality Assurance and Procurement Engineering Departments. During the surveillance NMPC will investigate how the equipment error occurred causing the pipe to be manufactured incorrectly, and why Sandvik concluded there was no systematic problem to address.
(Reference file code NMP94648)
Completion date: 11/30/99

Engineering Concurrence:
Procurement QA Concurrence:


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