IR 05000443/1993014

Insp Rept 50-443/93-14 on 930913-17.No Violations Noted. Major Areas Inspected:Whether Licensee Design,Installation & Mod of safety-related Piping & Pipe Supports Were Performed Per Regulatory Requirements

ML20059F594
Person / Time
Site:	Seabrook
Issue date:	10/18/1993
From:	Carrasco J, Modes M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20059F591	List: IR 05000443/1993014 ML20059F587
References
50-443-93-14, NUDOCS 9311050010
Download: ML20059F594 (9)

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U.S. NUCLEAR REGULATORY COMMISSION

REGION I

REPORT / DOCKET NOS. 50-443/93-14 LICENSE NO.

NPF-86 LICENSEE:

North Atlantic Energy Services Corporation Post Office Box 300 Seabrook, New Hampshire 03874 FACILITY NAME:

Seabrook Station INSPECTION DATES:

September 13-17, 1993

INSPECTOR:

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1. - t/ - 93 J. LMrfiico, Reactor Engineer Date Materials Section, EB, DRS f

APPROVED BY:

/0//#/f.8 Michael C. Modes, Chief D5te Materials Section, EB, DRS

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9311050010 931028 PDR ADOCK 05000443 G

PDR

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Areas Insoccted: A safety inspection was conducted to determine whether the licensee's

design, installation, and modification of safety related piping and pipe supports were i

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performed in accordance with regulatory requirements, engineering specifications and properly documented instructions. Further, the inspection determined whether snubber surveillance was performed as required by 10 CFR 50.55a(g), the Technical Specification (TS), the ASME Code Section XI, inservice Inspection / Inservice Testing (ISI/IST) and license commitments.

Results: Based on the review of sample modifications at the Seabrook Station, it was determined that the regulatory requirements are incorporated into the applicable piping design specifications and standards. The design of the supports in the selected modifications was performed in accordance with established engineering practices and current requirements.

During the course of the ISI program snubber functional test, a defective / damaged snubber support was identified. Piping analysis was performed to address the impact on the piping system due to the ISI finding. It was verified that the licensee's stress analysis showed that the snubber failure resulted in a negligible impact on the system and its components. While localized stresses and support loads may have increased, it was noted that at no time were piping Code allowables violated or support design capacity exceeded.

On September 16, 1993, the licensee identified that the snubber testing software had not been recorded in a software index as required by Section 3.6 of the North Atlantic Management Manual (NAMM) 18910. This administrative oversight did not adversely affect the performance and/or control of the test equipment or the software. However, the inspector expressed a concern regarding to the control, verification and validation of computer software utilized for tasks that are important to safety. The licensee acknowledged this concern and indicated that they were taking actions to address this issue.

The functional test was conducted with state-of-the-art technology by qualified individuals in a controlled environment. Additionally, the record keeping was found to be computerized and in compliance with the Technical Specification.

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DETAILS 1.0 PURM)SE AND SCOPE The purpose of this inspection was to determine whether the licensee's design, installation, and modification of safety related piping and pipe supports was performed in accordance with regulatory requirements, engineering specifications, industry standards and properly documented instructions. In addition, the inspection was conducted to determine whether the snubber surveillance was performed as required by 10 CFR 50.55a(g), the Technical Specification (TS), the ASME Code Section XI, and license commitments.

2.0 REVIEW OF TIIE PIPE STRESS ANALYSIS FOR MODIFICATION 90-042 (37700)

To assess the pipe stress analysis at Seabrook Station, the inspector selected a completed modification, No. DCR 90-042, which provides Seabrook with alternate _ spent fuel pool cooling. The inspector reviewed a sample of records and interviewed the cognizant engineer responsible for this modification. During the interview, critical points of the analysis method

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used to qualify piping systems and pipe supports were discussed.

Findings During the refueling outage, it is anticipated that, subsequent to defueling, both primary component cooling water (PCCW) train "A" and "B" would be taken out service to support retubing of heat exchangers 1-CC-E-17A and B Since the existing system is dependent on PCCW operation, an alternate cooling source was developed, and a third spent fuel (SF) heat exchanger was added and direct cooled by a cooling tower located adjacent to the spent fuel building.

This objective was accomplished under modification No. DCR-042 " Alternate Spent Fuel Pool Cooling." The inspector reviewed piping stress analysis and the pipe support design performed in the modification that installed an alternate spent fuel pool cooling, focusing on the technical adequacy as well as on the compliance with regulatory requirements, and industry standards.

Based on the review of the piping and pipe supports of this design modification package, and the interviews with the design engineers, the inspector noted that the piping stress analysis performed at Seabrook Station was done within the guidelines established in the following documents:

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Specification 9763-006-248-43, entitled " Design Specification for Nuclear Power Plant Systems" b)

NHY Procedure 36160, entitled " Engineering Design Standard for piping Systems"

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The inspector noted that the design bases within these documents concur with the Licensing commitments for piping established in the Updated Final Safety Analysis Report (UFSAR)

for Seabrook Station, hence conformance to these documents satisnes the FSAR commitments. Regulatory compliance was evident in calculation C-S-1-45157 analysis for spent fuel (SF) pump discharge piping, as modified by this modification No. DCR 90-42.

For example.

Seismic analysis has been performed utilizing the response spectrum approach, with

seismic data obtained from the " Amplified Response Spectra For Seismic Category I

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Structures." The site specific spectral response data was prepared in accordance with Regulatory Guide 1.60 with damping as prescribed in Regulatory Guide 1.61.

Prior to analysis, the response spectra curves were further modified by the application

of Code Case N-411 damping. As noted in Regulatory Guide 1.84 (Code Case Acceptability) the use of N-411 damping is conditional on five stipulations. The

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inspector verified that these conditions were met in the analysis performed by the licensee, these are:

1)

analysis is for piping only (no equipment) and the N-411 damped curves are used for the entire system 2)

response spectral analysis approach is utilized 3)

resulting pipe motion within new and existing support clearances are tabulated and reviewed, along with scismic accelerations of in-line components.

4)

no piping supports are of the energy dissipating type, i.e., crushable honeycomb 5)

there is no evidence of stress corrosion cracking Amplified Response Spectra modification to Code Case N-411 damping is achieved through the use of the " CARS" computer program ME-428, a QA qualified, benchmarked program maintained by Yankec Atomic Electric Co.

In the performance of the seismic analysis the "ADLPIPE" computer program was

utilized. Within that program the user invokes the requirements of Regulatory Guide 1.92 for seismic response model combination. Evidence of use of RG 1.92 is in the ADLPIPE input. Like the CARS program the ADLPIPE program is maintained by Yankee Atomic as part of their verified and validated computer software library.

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Conclusion In conclusion, regulatory compliance imposed by the Seabrook Station UFSAR is inherent in.

the applicable piping design specifications and standards, as evidenced in the performed piping stress analysis.

3.0 REVIEW OF TIIE PIPE SUPPORT DESIGN FOR MODIFICATION 90-042

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(37700)

The addition of the alternate spent fuel pool cooling piping system initiated via DCR 90-0042 prompted the need for new pipe support structures as well as modification to existing supports. The inspector verified that the latest support details were provided in Enclosure B of modi 6 cation package No. DCR 90-042. The inspector noted that the new and modified support structures were classified as either nuclear safety related (ASME III Class 3) or non-nuclear safety, seismically supported (NNS-1) and were designed in accordance with Engineering Design Standard 36260, Rev. O.

Two pipe supports 1845-SG-10 (Enclosure B, Page 67A) and 1845-SG-12 (Enclosure B, Page 67C) were selected as examples of the design / implementation process. Using loadings generated by the Mechanical Analysis Group and documented under Calculation C-S-45167,

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Revision 0, pipe support design qualification was provided under Calculation C-S-1-90044,

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Revision 0. Installation of the pipe supports was governed by Station Operating Procedure MSO517.03, " Installation of Piping, Pipe Supports."

The inspector noted that during installation of the subject supports it was observed that field conditions prevented the designs from being implemented as shown on the Change Authorization 00 details. Field Change Authorization 24 was issued in accordance with Chapter 2 of the Design Control Manual to resolve the installation problems. Support 1845-SG-10 was revised to correct a detailing error on the Bill of Material and to relocate the pipe support axially O'-7" to the east. This is an example of a well documented resolution of a field installation problem in which good communication between engineering and construction was evident.

Conclusion t

Based on the review of this sample, the inspector concluded that the design of the supports in.

this modi 6 cation were performed in accordance with established engineering practices and current requirements.

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6 4.0 PIPE STRESS ANALYSIS INTERFACE WITil INSERVICE INSPECTION The Mechanical Analysis Group (piping analysis) interfaces with the Inservice Inspection Program in those instances when, during the course of the ISI program a defective / damaged support is identified. Piping analysis is required to address the impact on the piping system, adjacent supports and associated equipment due to the ISI finding. Depending upon the type of finding, the piping system and its components may have operated in the "as-found" condition. Hence the original qualification analysis must be re-examined. During the second Refueling Outage three such instances occurred as follows.

1)

Snubber 821-RM-10 failed in testing due to high drag 2)

Snubber 1307-RM-50 found in the field in the locked position 3)

Snubber 1310-RM-37 found in the field in the locked position These findings were reported to Engineering via RES92-436 and RES92-462 (RES =

Request For Engineering Services) with the request to investigate the possible impact on the respective systems. These RES's were responded to by the performance of two pipe stress analysis calculations, namely C-S-1-45256 for RES92-436 (831-RM-10) and C-S-1-45258 for RES92-462 (1307-RM-50 & 1310-RM-37). The approach utilized in both these calculations was the same and is described as follows:

1)

The original As-built piping analysis ADLPIPE computer analysis was retrieved 2)

The retrieved analytical model was modified by replacing the failed snubber (failed in test or found locked) with a rigid support (worst case scenario)

3)

Re-analysis was performed with the modified input

4)

A comparison of results between the original qualifying analysis results and those obtained in the modified, locked snubber analysis which consisted of a review of pipe stresses, pipe support loads and equipment loads, where applicable.

Conclusion During the course of the ISI program, snubber functional test, a defective / damaged snubber support was identi5ed. Piping analysis was performed to address the impact on the piping

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system due to the ISI finding. The inspector verified that the licensee's results of this stress analysis showed that the snubber failure resulted in a negligible impact on the system and its components. While localized stresses and support loads may have increased, it was noted that at no time were piping Code allowables violated or support design capacity exceeded.

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5.0 REVIEW OF PROCEDURE FOR FUNCTIONAL EXAMINATION OF SNUBBERS The present snubber population at Seabrook is 286 from which 100 are hydraulic,20 steam generator, and 166 are mechanical. The inspector walked-through the functional testing facility and interviewed the personnel in-charge of the snubber functional test. In addition,

the inspector reviewed Procedure EX1805.03, Rev. 6. This procedure implements Technical Specifications for Seabrook sections 4.7.7 and 4.0.5 which addresses the precautions and limitations, snubber removal and installation, snubber bench testing and test completion for the functional testing. The procedure was found adequate.

The inspector verined that the functional test for mechanical and hydraulic snubbers, consisting of acceleration test, drag / breakaway test for mechanical and bleed rate test for hydraulic snubber are conducted with state-of-the art technology by qualiRed individuals in a controlled environment. The test report is generated in-situ, on a computerized form, and

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ready to be signed by the responsible reviewer. The dea consists of piston movement.

Lock-up and bleed are recorded and compared with the acceptance criteria.

The inspector reviewed the software that processes data collected by the data collection cells installed in the snubber bench test equipment and software. This software was purchased in 1985. Upon receipt, it appears that the licensee validated and verined this equipment and software by physically testing snubbers that had previously been tested by vendors and compared the known data with the resultant test data. This verification confirmed the accuracy and acceptability of the snubber bench test equipment and software. This method of equipment and software verification was consistent with sound engineering judgement and industry practices at that time.

In 1901, the licensee developed North Atlantic Management Manual (NAMM) 18910,

"Information Management Policy," which established consistent principles and practices for purchasing, developing, and maintaining software to create, store, and manipulate critical information in support of the licensee business and operational activities. This policy was based on guidelines established in ASME NAQ2, Part 2.7, " Quality Assurance Requirements of Computer Software for Nuclear Facility Applications," and governs software developed for safety critical and mission critical data.

Following the issuance of this policy, the licensee requested the snubber testing equipment vendor to develop a formal Validation and Verification (V&V) in accordance with the requirements of NAMM 18910. The vendor provided the formal V&V on October 28,1992. This V&V reconfinned that the snubber bench test software was performed in accordance with the requisite engineering specifications. North Atlantic subsequently incorporated guidance provided in the V&V into the snubber testing procedures.

It should be noted that no upgrades or revisions to the snubber bench test software have been made or requested since the receipt of the V&V.

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The inspector noted that on September 16,1993, the licensee identified that the smibber testing software had not been recorded in a software index as required by Section 3.6 of the North Atlantic Management Manual (NAMM) 1890. This administrative oversight did not adversely affect the performance and/or control of the test equipment or the software.

Although, the safety significance of this omission is low, the licensee stated that this was an isolated case and, following the identification of this deficiency, the licensee recorded the

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snubber testing software in a software index. The inspector had no further questions regarding this matter.

The inspector expressed a concern regarding the general control, verification and validation of computer software utilized for tasks that are important to safety. The licensee acknowledged this concern and indicated that they are taking the proper actions to address

this issue.

Conclusion Based on the review of functional tests, the inspector concluded testing was conducted with state-of-the art technology by qualified individuals in a controlled environment. Additionally, the record keeping was found to be computerized and in compliance with the Technical Specification.

6.0 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

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management at the September 17,1993 exit meeting. See Attachment 1 for attendance,

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ATT'CIIMENT 1

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Persons Contacted l

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North Atlantic Energy Services Corocration

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• J. M. Grillo Manager of Operations

• R. E. White

- Manager Mechanical Engineering

• B. Brian Mechanical Engineering Supervisor

- J. Sobotka NRC Coordinator -

• D. Egonis ISI Coordinator -

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• A. Bunting Lead Engineer

• G. A. Kann Program Support Manager i

• J. Warnock NSA M'anager

• J. O.Azzopardi Sr.QA Engineer

• T. F. Murphy Tech. Projects U.S. Nuclear Regulatory Commission

• R. Laura Resident Inspector s

• denotes thosh presen' at the exit meeting

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