05000443/LER-1998-001, :on 980103,inadequate ECCS Venting Surveillance Occurred.Caused by Not Using Piping Isometric Drawings in Selection of Vent Points,Inappropriately Crediting Dynamic Venting of Operating Pumps.Procedures Revised

:on 980103,inadequate ECCS Venting Surveillance Occurred.Caused by Not Using Piping Isometric Drawings in Selection of Vent Points,Inappropriately Crediting Dynamic Venting of Operating Pumps.Procedures Revised

ML20202B044
Person / Time
Site:	Seabrook
Issue date:	02/02/1998
From:	Peschel J NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:
Shared Package
ML20202B008	List: 05000443/LER-1998-001, :on 980103,inadequate ECCS Venting Surveillance Occurred.Caused by Not Using Piping Isometric Drawings in Selection of Vent Points,Inappropriately Crediting Dynamic Venting of Operating Pumps.Procedures Revised
References
LER-98-001, LER-98-1, NUDOCS 9802110070
Download: ML20202B044 (4)

LER-1998-001, on 980103,inadequate ECCS Venting Surveillance Occurred.Caused by Not Using Piping Isometric Drawings in Selection of Vent Points,Inappropriately Crediting Dynamic Venting of Operating Pumps.Procedures Revised

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability
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On January 3,1998 during a review of industry operating experience, North Atlantic determined that it had not adequately performed i ventjng of Emergency Core Cooling System (ECCS) components in accordance with Technical Specification (TS) Surveillann i

Requirement 4.5.2b.1. TS 4.5.2b.1 requires verification at least every 31 days that the ECCS piping is full of water by venting the ECCS pump casings and accessible discharge piping high points. The review identified: an accessible high point vent outside of conttinment that was not being periodically vented, as required by TC

• 5.2b.1; the practice of not venting the normally operating contrifugal charging pump (CCP) in 'he Chemical Volume and Control System (CVCS) and the Residual Heat Removal (RHR) pump, during shutdown cooling mode, was not in literal compliance with TS 4.5.2b.1; and, without the proper administrative controis, the TS ruquired periodic venting of the LCCS had rendered the High Head Safety injection (HHsi) and Intermediate Safety injnction (SI) subsystems inoperable when the vent valve was open.

These conditions were attributed to not using the piping isometric drawings in the selection of vent points; inappropriately crediting the dynamic venting of the operating pumps: and, lack of recognition o' the impact of reduced ECCS pump runout margin during venting activities.

The identified ECS high points and pump casings were venfied full of water; procedures were revmed to perform these activities in accorJance with TS 4.5.2b.1 and to provide administrative controls during venting activities. A Licensa Arnendment Rec: vest will also La tutwnitted to preclude the need to vent en operating CCP.

NRC FORM 366 (4 96) 9002110070 900202 PDR ADOCK 05000443' 8

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'* 1. NUCLI AR REoVLAToRY Commission to 914 UCENSEE EVENT REPORT (LER)

TEXT CONTINUATION FAClllTY NAME 11l DOCKET NUMsLR (2)

LER NUMBER 16)

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DC$C11pilon of Event Cn January 3,1990 during a review of industry operating experience, North Atlantic Energy Service Corporation (North Atlantic) determined that it had not adequately performed venting of Emergency Core Cooling System (ECCS) (BP & B01 components in accordance with Technical Specification (TS) Surveillance Requirement 4.5.2b.1.

TS 4.5.2b.1 requires serification at least every 31 days that the ECCS piping is full of water by venting the ECCS pump casings and accessible discharge piping high points. The review identifica en accessible high point vent (1St V230) outside of containment that was not.,eing periodically vented, as required by TS 4.5.2b.1.

The review further identified that the practico of not venting the normally operating contrifugal charging pump (CCP) in the Chemical Volume and Control System (CVCS) ICB1, which also serves as the Mgh head reafety injection (HHSI) 1001 pump during ECCS actuation; and, during shutdown cooling mode, the Residual Heat Removal (RHR) IDP) pump, which also serves as the low pr?ssure safety injection (LPSI) pump during ECCS actuation, was not in literal compliance with the prescriptive requirements of TS 4.5.20.1.

In addition, the review determined that, without the proper administrative controls, the TS required periodic venting cf the ECCS had rendered the HHSI and Intermediate Safety injection (SI) subsystems inoperable when the vent v lve was open. This determination is based on a scenario, whtareby; if a design basis accident occurred (with an ECCS pump in either subsystem f ailing to start) concurrent with venting activities in progress on olther the HHSI cr Si systems, then, should the vont valve (s) not be reclosed the additional flow out of the vent path could cause the single operable HHSI or Si pump to exceed runout flow conoitions.

The inadequate surveillar.co monitoring of the high point vent (1SI V236) and not venting the operating CCP and RHR pumps were determined to be a missed surveillance. This represents a condition psohibited by the Technical Sp;cification and is reported pursuant to s0 CFR 50.73 (a)(2)(i).

T o rendering of portions of the ECCS inoperable during the TS 4.5 2b.1 required wenting routines is reported pursuant to:

10 CFR 50.73 (a)(2)(ii)(B), as a condition that was outside the design basis of tne plant, o

10 CFR 50.73 (a)(2)(v)(B&D), as an event or condition that alone could have prevented the fulfillment of the o

safety function of structures or systems needed to remove residual heat or mitigate the consequonces of an e

accident, and; 10 CFR 50.73 (a)(2)(vii)(B&D), as an event that where a single cause or condition caused at least one o

independent train or channel to become inoperable in multiple systems or two independent trains or channels to become inoperable in a single system designed to remove residuel heat or mitigate the s.onsequences of an accident.

11. Cause of Event

The surveillance inadequacy for not including high point vent SI V236 into surveillance procedures was cttributed to not using piping isometric drawings in the selection of vent points for routine surveillance monitoring during the initial procedure development stage nor during subsequent procedure reviews. The surveillance inadequacy for not venting the operating CVCS CCP and RHR pumps was attributed to crediting the dynamic venting action of the pump (s) in operation as meeting the requirement to ensure that the ECCS pumpI 1

NHc FORM 366A' u.S. NUCLEAR RLoulAToRY Commission to su UCENSEE EVENT REPORT (LER)

TEXT CONTINUATION DOCKET NufABER !2)

LLR NUMBER (e)

PAoE (3) rACILITY NAME (1) 05000443 YLAR SLOulNilAL 1EVI5 ion Seabrook Station NuWR NuWn 3 of 4 001! -

98 00 iEXT (11 rnore space is reousted, use edditionalvtvues of NRC form 366M (11l c: sings were vented. Collectively these conditions represent inadequacies in translating TS 4.5.2b.i r;quirements into appropriate surveillance activities.

The surveillance inadequacy for not including appropriato administrative er.ols for venting activities into the surveillance procedure, to ensure that the integrity of the ECCS flowpetn(s) would be immediately restored foll wing system actuation, is attributed to a lack of recognition of the impact of reduced ECCS pump runout mitgin during venting activities.

Ill. AnalyslimLEvent This event was significant because inadequate venting of the ECCS piping and pump carings has the potential to subject ECCS piping to hydraulic transients during ECCS actuation, and the potential to cause gas binding of the ECCS pumps so as not to deliver the design ECCS flow to the Reactor Coolant System (RCSh However, there were no adverse safety consequences resulting from this event in that: subsequent venting of the subject s:ction of ECCS piping revealed no alt / gas accumulation and that the piping was full of water. With exception of the operating CCP, the ECCS pumps were wnted with no alt / gas observed. The operating CCP was vented by clignment of the minimum flow recirculation line to the top of the volume control tank (VCT).

Lcck of appropriate administrative controls during venting activities has the potentief.o subject the HHSI and Si cubsystem pumps to exceed runout conditions during a design basis accident (DBA). Specifically, if a design b: sis accident occurred (with an ECCS pump in either subsystem f ailing to start), cuncurrent with venting cctivities in progress on either the HHSl or SI systems, then, should the vent valve (s) not be reclosed the additional fi:w out of the vent path could cause the single operable HHSt or Si pump to exceed runout flow conditions. A pump in runout condition would not be able to deliver the design ECCS flow to the RCS, Recent engineering cn: lysis determined that flow margins for the HHSI and Si pumps were near runout flow conditions. A further cycluation, specific to the opening of vont valves, concluded that runout flow conditions would be exceeded if cne or more vent valves in the flowpath remained open during ECCS actuation, hence the need for administrative controls. The analysis for use of administrat.'ve controls concludes, in part: that, with a nuclear system operator (NSol in constant communication with the control room during venting activities, the manual ap:tators on the vent valves are sufficiently sized so that a N;..

'd overcome the differential pressure across cn open or partially open vent valve during ECCS actuation and close the vent valve.

At the time of discovery, the plant was in Mode 5 operation, whereby, operability of ECCS is not required by Tcchnical Specifications.

IV. Conccilv3 taction North Atlantic formed an Event Evaluation Team to investigate practices assoristed with compliance to TS 4.5.2b.1 tequirements. North Ath ntic performed a detai!ed review of ECCS piping isometric drawings and performed walkdowns to identify piping high points, both accessible and inaccessible. Upon identification of the missed high point vento fiorth Atlantic vented the subject high point (1SI V236) with no air / gas observed.

Subsequently, ECCS piping high points were confirmed to be full of water either by venting or ultrasonic testing.

Proceduro changes to surve;ilance procedure OX1456.02, "ECCS Monthly Valve Verification," were made to include the additional high point vent (1SI.V236) and perform venting of the operating ECCS pumps. With exception of the operating CCP, the ECCS pumps were manually vented with no air / gas observed. The operating NRc f OHM 366A 14 s10

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U.S. NUCLEAR REouLAToRY Commission (4 std' UCENSEE EVENT REPORT (LER)

TEXT CONTINUATION F AcluTY NAME til DOCKET NUMBER (2)

LER NUMBER (6)

PAoE 13) 05000443 YEAR f>EQuENilAL

%EVislON Seabrook Station NMR NUM 4 of 4

- 98 001 00 TEMT W more space is required, use additionalcopies of NRC form 366A) (11)

CC.P was vented by alignment of the minimum flow tecirculation line to the top of the volume control tank (VCT).

This method of venting does not allow visual confirmation of the presence of alr/ gas because the VCT cannot be accessed, however, it is a ! Nh point in the system which allows the gasses to be vented. Additional changes w:re made to OX1456.02 for venting piping high points and ECCS pump casings other than the operating CCP to record the observance of alt / gas, notification to shif t man.Noment if an unusual amount of alt / gas is observed, and dir:ction to perform ultrattonic testing of certain inaccessible high points if air / gas is d*tected at particular vents.

X Upon determination tf 3t the opening of a single vent valve could potentially subject the niiSI and Si pumps to 4

- exceed runout flow conditions, surveillance procedure OX1456.02 was revised to include specific idministrative p

c:ntrols during venting evolutions.

A License Amendment Request will be submitted to revise TS 4.5.2b.1 to preclude the need of venting an cperating CVCS CCP.

V. Additional Inf otmanon N:ne.

Similar Events

S:abrook Station has experienced other instances in which Technical Specification surveillance requirements hav3 been missed because the surveltlance procedures were not all encompassing to fully demonstrate compliance with surveillance requirerrents. Of these events, none have similarity; since.the majority of these are casociated with circuitry / software testing and/or calibrations. This event is the first of its kind, whereby, non compliance with a surveillance requirement was not-recogr.lzed because of: the lack of using piping -

isometric drawings, during the procedure development stage, did not encompass all accessible high point vents:

in:ppropriate crediting for dynamic venting of pumps; and, lack of recognition that administrative controls were r quired during venting activities so es not to make portions of the ECCS inoperable.

Although not a simitar event, in July 1994, North Atlantic submitteri e voluntary LER, 94 009 00, to document c c:nriition where the SI pumps had the potential to exceed their runout flow rate. The condition reported could unty have existed following a large break LOCA af ter hot leg recirculation had been initiated where the SI-pumps are receiving suctlon boost from the RHR pumps. There were no adverse safety consequences as a r:sult of this condition because the condition would have occurred after the Si pumps fulfilled their intended s:f ty function, since they are explicitly relied upnn during the injection phase. The Si pumps are not, however, explicitly relied upon during the recirculation phase of core cooling following RCS depressurization. For a depressurized RCS one train of GHR is capable of providing adequate flow to ensure core cooling and mitigation cf boron precipitation. When the condition was made known North Atlantic rebalanced the Si hot leg flow to cnsure Si pump runout was not exceeded. The event reported by LER 98 00100 is associated with a potential adverse condition during the ECCS injection phase.~

Manuf acturer Data

- Nst applicable.-

. NRC FOMM 366A 44-96)