05000245/LER-1996-051, :on 960913,seismic Qualification Deficiencies Found in SR Piping.Caused by Original Plant Design Deficiency.Reviewed All SR Piping Sys to Identify Addl Design Deficiencies

:on 960913,seismic Qualification Deficiencies Found in SR Piping.Caused by Original Plant Design Deficiency.Reviewed All SR Piping Sys to Identify Addl Design Deficiencies

ML20132C753
Person / Time
Site:	Millstone
Issue date:	12/13/1996
From:	Robert Walpole NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20132C735	List: 05000245/LER-1996-051, :on 960913,seismic Qualification Deficiencies Found in SR Piping.Caused by Original Plant Design Deficiency.Reviewed All SR Piping Sys to Identify Addl Design Deficiencies 05000245/LER-1996-051-01, Forwards Suppl LER 96-051-01.Commitments Listed,Including Implementation of Mods to Restore Each Identified Piping Sys to Design Basis
References
LER-96-051, LER-96-51, NUDOCS 9612180451
Download: ML20132C753 (4)

LER-1996-051, on 960913,seismic Qualification Deficiencies Found in SR Piping.Caused by Original Plant Design Deficiency.Reviewed All SR Piping Sys to Identify Addl Design Deficiencies

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii) 10 CFR 50.73(a)(2)(ii)
2451996051R00 - NRC Website

text

!

~

NRG FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMS NO.3160-0104 R 95)

EXPIRES 04/30/98 oYa'T?oEcoNECTlo E'ST RE

$0 F

TEo $$

nu"'?o^"A#a"R ^^M3.o' nann %inePJo^W!:

LICENSEE EVENT REPORT (LER)

!**1"oTN"u'cT""A'o?a^T&a'EJJ,"s'#%"!,"!,,"#s." &

!?in%"s'Jo2#l#!"M"T"n%21"o?"#'fo'dP"' *-

(See reverse for required number of digits / characters for each block)

FAC1 TTY NAME (1)

DOCKET NUMBER (2)

PAGE (3)

Millstone Nuclear Power Station Unit 1 05000245 1 of 4 TITLE 44)

Seismic QuaHfication Deficiencies Found in Safety Related Piping EVENT DATE (5)

LER NUMBER (6)

REPORT DATE (7)

OTHER ~4CILITIES INVOLVED (8)

MONTH DAY YEAR YEAR SEQUENTIAL REVISION MONTH DAY YEAR FACIUTY NAME DOCKET NUMBER NUMBER I

11 13 96 96 051 01 12 13 96 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check one or more) (11) l MODE (9)

N 20.2201(b) 20.2203(aH2)(v) 50.73(a)(2)(i) 50.73(a)(2)(viii)

POWER 20.2203(aH1) 20.2203(a)(3)(i)

X so 73(aii23(ii) so.73(aH2)(x)

LEVEL (10) 000 20.2203(aH2Hi>

20.2203(aH3)(ii) 50.73(aH2)(iii) 73.71 20.2203(aH2Hii) 20.2203(a)(4) 50.73(aH2)(iv)

OTHER

)

20.2203(a)(2)(iii) 50.36(c)(1) 50.73(aH2)(v) specify in Abstract below I

or in NRC Forrn 366A 20.2203ta)(2)(iv)

So.36( H2)

So.73(a)(2Hvii)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER linctuos Area Codel l

Robert W. Walpole, MP1 Nuclear Licensing Manager (860)440-2191 I

COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTEM COMPONENT MANUFACTURER REPORTABLE CAUSE 4 SYSTEM COMPONENT MANUFACTURER REPORTABLE TO NPROS TO NPRDS i

SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED MONTH DAY YEAR SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE).

l

[ YES NO 1

30 97 ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

On September 13,1996, with the plant in the COLD SHUTDOWN condition, it was determined that several piping lints that form part of the Turbine Building Secondary Closed Cooling Water (TBSCCW) system and the Condensate system are not seismically qualified. Most of the associated lines were operable while a small number of the lines an qurstion did not meet the operability guidelines established in Generic Letter 91-18. The lines ranged from 3/4 inch to 4 inches in diameter. On September 13,1996, it was determined that the lack of seismic qualification for these lin:s which form part of the TBSCCW and Condensate systems resulted in the plant being outside of its design bisis, and a prompt report was made pursuant to 10CFR50.72(b)(2)(i). On November 13,1996, with the plant in tha COLD SHUTDOWN condition, it was determined that several additional piping lines that form part of the Feedwater, Fuel Pool Cooling, Low Pressure Coolant injection, Isolation Condenser, and Reactor Water Cleanup systems are not seismically qualified. A prompt report was made pursuant to 10CFR50.72(b)(2)(i). These events are reportable pursuant to 10CFR50.73(a)(2)(ii) as a condition outside the design basis of the plant.

The cause of these events is an original plant design deficiency. Corrective actions will include modifications to l

restore these lines to design basis, as well as a review of all safety related piping systems to identify any additional design deficiencies. There were no safety consequences as a result of this event.

9612180451 961213 PDR ADOCK 05000245 S

PDR

.~.

NRC, FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REVISION Millstone Nuclear Power Station Unit 1 05000245 NUMBER NUMBER 2 of 4 96 051 01 1

TEXT (11more space is required, use additional copies of NRC Form 366A) (17) l.

Description of Event

On September 13,1996, with the plant in the COLD SHUTDOWN condition, it was determined that several piping lines that form part of the TBSCCW system and the Condensate system are not seismically qualified.

i On November 13,1996, with the plant in the COLD SHUTDOWN condition, it was discovered that several additional piping lines that form part of the Feedwater, Fuel Pool Cooling, Low Pressure Coolant Injection, j

Isolation Condenser, and Reactor Water Cleanup systems are not seismically qualified. Most of the I

associated lines were operable while a small number cf the lines in question did not meet the operability guidelines established in Generic Letter 91-18. Specifically, the following are lines that do not meet the

[

operability criteria: (1) TBSCCW system: 1" SC-107 piping that branches off 3" SC-19 near HVAC-1 and y

HVAC-2,1" SC-108 piping that branches off 3" SC-20 near HVAC-1 and HVAC-2, two 1" lines that connect to the TBSCCW surge tank; (2) Condensate system: Condensate demineralizer piping connected to demineralizer tanks M2-8A,B,C,D,E,F, and G,1/2" C-83 piping that extends from 3/4" C-50 to 16" C-82; l

(3) isolation Condenser: 1" piping associated with level switches LS-1347A,B, and C, 3" IC-12 makeup water supply piping. The lines addressed by this LER range from 3/4 inch to 4 inches in diameter. All of i

these lines were identified under the Northeast Utilities Significant Operating Event Report (NUSOER) 92-02 Program for Millstone Unit No.1, which is reviewing all safety related piping systems and evaluating any l

l lines that were not previously qualified. The lines addressed by this LER are mostly small bore (2" nominal pipe size and under) branch lines which are connected to large-bore process pipes that have been seismically qualified. The deficiencies noted in the effected lines consist primarily of excessively long spans lacking adequate lateral support, and inadequate capacity in existing supports to resist predicted loads. These configurations result in piping stresses which exceed Code allowable limits for load combinations (deadweight, internal pr' essure, and seismic inertia) specified by the Millstone Unit No.1 Upaated Final j

1 Safety Analysis Report, Chapter 3.

The lack of seismic qualification for these lines which form part of the TBSCCW, Condensate, Feedwater, Fuel Pool Cooling, Low Pressure Coolant injection, Isolation Condenser, and Reactor Water Cleanup systems resulted in the plant being outside of its design basis. A prompt report was made pursuant to 10CFR50.72(b)(2)(i) on September 13,1996, and November 13,1996.

i

{

There were no safety consequences as a result of this event.

l 11.

Cause of Event

i The cause of this event is twofold, insufficient scope and inadequate design. Insufficient scoping at the time of implementing !EB 79-14 is the result of the lack of a clear definition of seismic class I system boundaries at the time the IEB 79-14 scope was established. This work was initiated prior to the existence of QA boundaries such as are currently depicted in the MEPL for Millstone Unit No.1. The absence of this information resulted in the IEB 79-14 scope falling short of what we currently define as a QA boundary. In addition to this, the IEB 79-14 specifically excluded most small bore piping thus the field verification

]

conducted on large bore piping was not completed for small bore piping, i

l Secondly, the inadequate design issue is associated with original plant construction. Most safety-related small bore piping at Millstone Unit No.1 was " field run" without drawings, using span charts to locate standard support designs. This resulted in the field condition lacking the design and installation controls afforded large bore piping and supports. This method of design, while z.n accepted industry practice, resulted in installations which were not fully in compliance with the units design basis.

NGC FORM 366A (4-95)

NEC FO.iM 3F ^A U.S. NUCLEAR REGULATORY COMMISSION W95)

UCENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REVISION Millstone Nuclear Power Station Unit 1 05000245 NUMBER NUMBER 3 of 4 96 051 01 TEXT fit more space is required, use addi:ional copies of NRC Form 366A) (17) j Ill. Analysis of Event The lack of seismic qualification for the lines addressed by this LER, which form part of the TBSCCW, Condensate, Feedwater, Fuel Pool Cooling, Low Pressure Coolant Injection, Isolation Condenser, and Reactor 1

Water Cleanup systems, results in the plant being outside of its design basis and is reportable pursuant to 10CFR50.73(a)(2)(ii). The piping lines addressed by this LER are distributed throughout these systems and could effect their operability, via loss of pressure boundary integrity during a seismic event. Since there have been no seismic events, the safety consequence of this event is low.

The Millstone Unit No.1 TBSCCW system is a closed loop system providing cooling to various equipment located in the reactor and turbine building. The safety significance of the TBSCCW system is related to the dependency of both the plant's ventilation and Feedwater Coolant injection (FWCl) system on it's operation.

Certa'n turbine building area coolers are required to maintain area temperatures for operability of FWCl i

components, and the emergency diesel generator. The Condensate system's safety related functions include supply of make-up water to the reactor vessel as part of the FWCl system, and make-up water to the spent fuel pool via the skimmer surge tanks. The Feedwater system also serves as part of the FWCl system. The portion of the Fuel Pool Cooling system addressed in this LER is the reactor cavity drain line. Low Pressure Coolant injection, Isolation Condenser and FWCl are ECCS systems. Portions of the Reactor Water Cleanup system provide primary coolant and containment boundary. The lines addressed by this LER are inadequately supported to meet design basis seismic requirements, and in several cases, cannot meet operability requirements. Specifically, the following are lines that do not meet the operability criteria: (1) TBS.CCW system: 1" SC-107 piping that branches off 3" SC-19 near HVAC-1 and HVAC-2,1" SC-108 piping that branches off 3" SC-20 near HVAC-1 and HVAC-2, two 1" lines that connect to the TBSCCW surge tank; (2)

Condensate system: Condensate demineralizer piping connected to demineralizer tanks M2-8A,B,C,D,E '

and G,1/2" C-83 piping that extends from 3/4" C-50 to 16" C-82; (3) Isolation Condenser: 1" pip associated with level switches LS-1347A,B, and C, 3" IC-12 makeup water supply piping. Thus, their los.

function could impair the ability of the TBSCCW, Condensate, and Isolation Condenser systems from performing their safety-related functions.

The effect of these inoperable lines on the function of these systems will first be addressed individually.

Failure of the identified small-bore lines which form part of the TBSCCW pressure boundary could result in loss of sufficient inventory to render the system inoperable. This could result in the loss of the emergency diesel generator and the FWCl systems. Failure of the identified lines which form part of the Condensate system pressure boundary could resu4 in loss of sufficient inventory to render the FWCl system inoperable.

i The Millstone Unit No.1 Final Safety Analysis Report, Chapter 15 analysis does nst credit the FWCl system.

l Failure of the identified lines which form part of the Isolation Condenser shell side pressure boundary could result in loss of sufficient inventory to render the Isolation Condenser system inoperable. Although the l

Isolation Condenser system is credited for Loss of Coolant Accident (LOCA) mitigation, the single iBilure assumed in the analysis disabled it along with the emergency diesel generator. Thus, acceptable resu:ts of LOCA analysis have been demonstrated without the benefit of the Isolation Condenser system.

Evaluations are ongo;ng as to the seismic adequacy of Gas Turbine and ECCS system associated components. Additionally, these systems (TBSCCW, Condensate, and Isolation Condenser) are credited as forming part of safe shutdown methods in other plant programs. Therefore, upon completion of the reviews associated with the NUSOER 92-02 program, and other ongoing seismic evaluation programs, an analysis of

\\

t NRQi'ORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4 93)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL REVISION Millstone Nuclear Power Station Unit 1 05000245 NUMBER NUMBER 4 of 4 96 051 01 i

TEXT (If more space is required use additional copies of NRC Form 366A) (17) the seismic adequacy of Millstone Unit No.1 safe shutdown methods will be performed, considering the cumulative effect of the resultant findings.

IV. Corrective Action

As committed to in LER 96-040-00, Commitment No. B15757-2, in order to ensure that all safety related r

piping systems meet design basis seismic requirements, the NUSOER 92-02 program will verify that i

existing piping evaluation programs such as IEB 79-14 have fully addressed the applicable scope.

l 1

l Northeast Nuclear Energy Company (NNECO) will implement modifications to restore each identified piping j

l system to design basis requirements prior to startup for operating cycle 16. NNECO will supplement this LER with the results of the ongoing NUSOER 92-01 Program review by January 30,1997.

I i

l NNECO will perform an analysis of the cumulative effects of the results of efforts which are reviewing the j

j seismic adequacy of Millstone Unit No.1 systems and components on credited safe shutdown methods.

l This review will be initiated upon completion of seismic evaluation programs, and will be completed by June 30,1997, i

V.

Additional information

l t

Similar Events

t i

I LER 92-004, " Diesel Generator Air Start and Wall Seismic Modifications," addressed the lack of seismic qualification for the Millstone Unit No.1 Emergency Diesel Generator Air Start Piping.

LER 93-004, " improperly Restrained Main Steam Venturi instrument Lines", discussed inadequate seismic supports on a small bore line inside the drywell. The corrective actions included an inspection of additional pipe supports on similar small bore lines in the drywell.

1 LER 96 040, " Control Rod Drive System Seismic Inadequacy Caused Plant to be Outside of its Design Basis", discussed the seismic design inadequacy of the Control Rod Drive system insert and withdrawal piping. Corrective actions included restoration of the system to design basis, and review of all safety related piping under NUSOER 92-02.

Manufacturer Data 1

None i

l J

),

1