IR 05000213/1993014

Insp Rept 50-213/93-14 on 930719-23.No Violations Noted. Major Areas Inspected:Determination of Whether Licensee Design,Installation & Mod of safety-related Dynamic Pipe Restraints & Static Pipe Supports Performed Correctly

ML20024H982
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	08/03/1993
From:	Carrasco J, Gray E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20024H979	List: IR 05000213/1993014
References
50-213-93-14, NUDOCS 9308310065
Download: ML20024H982 (8)

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U.S. NUCLEAR REGULATORY COMMISSION

REGION I

Report No.

50-213/93-14 Docket No.

50-213 Licensee No.

DPR-61 Licensee:

Ccnnecticut Yankee Atomic Power Company Northeast Nuclear Energy Company Post Office Box 270

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Hartford, Connecticut 06141-0270 Facility Name:

Haddam Neck Inspection At:

Haddam. Berlin, CT.

Inspection Conducted: July 19-23,1993

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l-3 -9 5 Inspectors:

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s J. E.'1"Trrasco, Reactor Engineer, date Materials and Processes Section, EB,DRS Y

3 Approved by:

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E. H. Gray, Chief, Materials date EB,DRS 9308310065 930825 PDR ADOCK 05000213

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Areas Inspected: An announced safety inspection was conducted to determine whether the

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licensee's design, installation, and modification of safety-related dynamic pipe restraints (DPRs) and static (rigid) pipe supports were performed in accordance with regulatory requirements, engineering specifications and properly documented instructions. In addition, the inspection was conducted to determine whether the snubber surveillance program was performed as required by 10 CFR 50.55a(g), Technical Specification (TS), ASME Code Section XI, and license commitments.

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Results: During the review and inspection of piping and pipe supports at Haddam Neck, the inspector noted that for the safety-rela'ed Class I piping and associated supports, there are no outstanding items of safety concern. Based on the programmatic review of the ISAP, Topic

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1.04, - Seismic Qualification of Safety-Related Piping, sample system walkdown, and the review of the selected sample of design calculations, of pipe supports, the inspector concluded that the licensee is implementing the Integrated Safety Assessment Program ISAP Topic 1.04 effectively. The licensee plans to confirm the seismic adequacy of the plant's

remaining supports in the main steam, feedwater, and service water systems piping by using the seismic margins methodology. This proposed methodology was submitted to the NRC on July 9,1993.

Based on the interviews with the ISI/IST personnel, observations of components in the plant

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and review of procedures and documentation, the inspector concluded that the mechanical l

snubber surveillance and testing program is conducted in an effective and efficient manner.

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Performance of the visual and functional snubber tests were conducted in accordance with

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approved procedures and the Technical Specifications.

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DETAIIE

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1.0 PURPOSE AND SCOPE The purpose of this inspection was to determine whether the licensee's design, installation, and modi 5 cation of safety-related dynamic pipe restraints (DPRs) and static (rigid) pipe

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supports were performed in accordance with regulatory requirements, engineering

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speci5 cations and properly documented instructions as well as to determine whether the j

snubber surveillance program was performed as required by 10 CFR 50.55a(g), Technical Specification (TS), ASME Code Section XI, and licensee commitments.

2.0 REVIEW OF IIADDAM NECK STATUS OF PIPE SUPPORTS (50090/70370)

The inspector reviewed a sample of records of piping analysis and associated pipe supports and interviewed the cognizant engineer for pipe supports with the following results.

2.1 Rackground

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In the early 1980s, the Nuclear Regulatory Commission (NRC) implemented a program of reviews of older operating commercial nuclear power plants. This program was named the

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Systematic Evaluation Program (SEP). The SEP grew out of a concern that some older plants were licensed under regulations that were less stringent than those in existence today.

b Through SEP, the NRC recognized a need to provided order and ef5ciency in the implementation and resolution of regulatory requirements for operating nuclear plants. The experience gained from SEP enabled the NRC to develop a new and integrated approach called Integrated Safety Assessment Program (ISAP). In early 1985, the NRC implemented

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a pilot program for ISAP in which two volunteer plants, Millstone 1 and Haddam Neck,

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were examined.

2.2 Findings As part of the Haddam Neck Plant SEP review (Topic Ill-6), the licensee initiated an

extensive reanalysis program to perform stress analysis of safety-related piping systems using as-built piping isometrics and support information developed under the IE Bulletin 79-14.

Under the IS AP Topic 1.04, Seismic Quali5 cation of Safety-Related Piping, the licensee analyzed piping systems greater than two-inch nominal pipe size which are needed or can be used to achieve and maintain the plant in a safe shutdown condition for a Safe Shutdown Earthquake (SSE) loading condition. ISAP Topic 1.04, includes the following systems: main steam, main feedwater, auxiliag feedwater, residual heat removal, low pressure safety injection, high pressure injection, chemical and volume control, and service wate.

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The inspector verified that currently, the licensee has an NRC approved Site Specific

Response Spectra, developed along with piping analysis criteria. ASME Code Case N-411, which enables the licensee to use higher damping values to reduce the number of pipe supports, was approved by the NRC for use at Haddam Neck. With these approved tools,

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the licensee has being analyzing, modifying, and installing supports for the last 10 years.

The licensee stated that all the systems inside the containment are essentially complete along with a major portion of the systems outside containment, t

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The inspector reviewed the licensee ISAP records for safety-related piping. Although, the licensee's licensing and engineering departments have being maintaining an adequate tracking system, project status on the safety related piping was not readily available. Based on the

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review of the licensee ISAP records on safety-related piping, and interviews with licensing and stress engineers, the inspector concluded that the licensee has divided the seismic pipe

supports into several groups to be evaluated individually. The current status is tabulated below.

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System Building Supports Engineering Construction Remaining and Design Schedule Schedule Main Steam Containment

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Complete Complete (incl. 26 MS Drains)

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1992-1993 See Note 1 Containment Feedwater Containment

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Complete Complete

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1992-1993 See Note 1 Containment

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Auxiliary Containment

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Complete Complete Feedwater Turbine

1992-1993 1993-1996 Building RHR Containment

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Complete Complete

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Primary

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Complete Complete Auxiliary Building (PAB)

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System Building Supports Engineering Construction Remaining and Design Schedule Schedule l

CVCS Containment

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Complete Complete

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Safety injection Containment

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Complete Complete Safety injection PAB

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Complete Complete-Service Water intake

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Complete Complete PAB

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1990-1992 1993-1995 Diesel Gen.

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Complete Complete Containment

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Complete Complete

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Reactor Containment

Complete See Note 2 Coolant Note 1.

To analytically demonstrate that the main steam and feedwater piping will remain intact subsequent to a seismic event.

Note 2.

Support to be installed with valve replacement for ALARA concerns.

The licenre has submitted a letter to the NRC, dated July 9,1993, requesting their intention to explore the use of Seismic Margins Methodology which is based on actual earthquake experience. This method would be used to seismically qualify these remaining supports.

Meanwhile, the licensee added that there is no immediate safety concerns. This affirmation was officially submitted to the NRC in a form of Justification for Continued Operations (JCO). The inspector has no further programmatic questions regarding ISAP, Topic 1.04.

For the review of the implementation of the seismic upgrade of piping, ISAP Topic 1.04, the

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ins 9ector and the stress engineer walked down portions of the Service Water piping system located in the intake structure (drawings 20231-SH-144ZA and 20231-SH-144A). During the walkdown, it was observed that the licensee has performed a substantial amount of seismic upgrading. Furthermore, the inspector selected a support No. WS-2007, which is a three-way restraint (axial, vertical and lateral). The support which is a massive space frame, appeared to be properly anchored and the structural members (tubes steel) appeared to be properly welded. To assess its design, the inspector verified that the magnitude and direction

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of the support loads calculated in the pipe stress problem No. 81-057-043-GP, Rev. 2, were properly applied in the qualification of support No. WS-2007, the calculation was found to be technically adequate and conservative. The inspector has no further questions regarding the qualification of support WS-2007.

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i 2.3 Conclusion Based on the programmatic review of the ISAP, Topic 1.04, - Seismic Quali6 cation of

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Safety-Related Piping, the sample system walkdown, and the review of the selected sample of pipe supports, the inspector concluded that the licensee is implementing the ISAP Topic 1.04 effectively. However, the licensee plans to confirm the seismic adequacy of the plant's main steam, feedwater, and service water systems' piping by using the seismic margins

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method. This proposed method was submitted to the NRC for review on July 9,1993.

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3.0 ISI/IST SNUBBER SURVEILLANCE PROGRAM AT IIADDAM NECK (70370)

3.1 Background

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i Snubbers are restraining devices used to control the movement of pipe and equipment during abnormal conditions such as seismic events, turbine trips, safety / relief valve discharge, and

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rapid valve closure. Snubbers permit displacement of the pipe as a result of slow movements such as thermal expansion, but restrain rapid motions such as those induced by earthquakes and water hammers. However, while snubbers present convenient solutions in design and

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analysis, the use of snubbers has proved to have many practical and economic disadvantages.

Malfunction of snubbers in the lockup mode during normal plant operation has created unanticipated high pipe thermal stresses. Because of these hardware problems, snubbers have contributed to the escalating maintenance cost partially as a result of inservice inspection and testing requirements. Industry experience has shown that piping systems often have more snubbers than are actually required for protecting the piping from rapid motion.

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3.2 Findings Haddam Neck's current total snubber population is thirty-six (36) mechanical snubbers.

These snubbers are divided into seven groups representing different piping systems. The

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inspector veri 6ed that during this last outage, ten percent of each group was functionally tested in a bench test located in Millstone. These functional tests were performed in accordance with the Technical Specification 3/4.7.4 (d).

During the inspector's review of information regarding the snubber testing activities, records showed that snubber No. DRH-ASS-1659A with a serial No.21644 was packaged and

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shipped to Millstone for functional testing. Upon testing the snubber at Millstone, it was found to be frozen. A possible cause of the lockup, the licensee indicated, was caused by the removal of the snubber end cap. The end cap is transferred from the removed snubber to the replacement snubber. When the end cap was removed, the snubber was subjected to a twisting torque from one end of the snubber to the other. The licensee added that these snubbers model PSA 1/4 are delicate and cannot withstand any end to end twisting forces. A

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second possible root cause of lockup was snubber damage while handling and shipping to Millstone testing facility. Due to this snubber failure, an additional snubber in the Loop

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Drain System was tested (DRH-2220 Serial No.36530). This snubber passed its functional

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testing. In regard to the failed snubber, the licensee is still investigating this problem. The I

licensee is looking at corrective actions which would include possible procedure upgrade and mechanical snubber training. The inspector had no further questions in this regard.

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In addition, during a visual inspection, it was noted that snubber No. RC-V-21X with serial No.11213 had a light coating of boric acid. The snubber was stroked and sent to Millstone

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for functional te-sting. This snubber passed its functional test. Snubber 11213 was replaced

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with a spare. A nonconformance report (NCR) was written to test and reinstall or replace the snubber. The clamp assembly was cleaned and the installation was inspected. The inspector had no further questions in this regard.

i 3.3 Conclusion l

Based on the interviews with the ISI/IST personnel, the inspector concluded that the

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mechanical snubber surveillance and testing program is conducted in an effective and I

efficient manner. The visual and functional snubber tests are conducted in accordance with an approved procedure and the Technical specifications.

4.0 MANAGEMENT MEETINGS i

Licensee management was informed of the scope and purpose of the inspection at the beginning of the inspection. The findings of the inspection were discussed with the

licensee's management at the July 23,1993, exit meeting. The licensee did not take issue with the findings of the inspector. See Attachment 1 for attendance.

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ATTACIIMENT 1 Persons Contacted Connecticut Yankee Atomic Power Company

• M.

Kupinski Manager, Mechanical and Civil Engineering

• T. J. Mawson Supervisor Stress Analysis

• K. M. Sickles Senior Engineer S.

Pornprasert Stress Analysis Engineer

• E.L. Annino Senior Analyst

• G.P. Van Noordenner Licensing Supervisor

• J.L. DeLawrence ISI Engineer U.S. Nuclear Regulatory Commission

• W. J. Raymond Senior Resident Inspector

• denotes those present at the exit meeting

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