Information Notice 1993-67, Bursting of High Pressure Coolant Injection Steam Line Rupture Discs Injures Plant Personnel

Bursting of High Pressure Coolant Injection Steam Line Rupture Discs Injures Plant Personnel

ML031070135
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000349, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	08/16/1993
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-93-067, NUDOCS 9308100248
Download: ML031070135 (14)

U -AU UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 August 16, 1993 NRC INFORMATION

NOTICE 93-67: BURSTING OF HIGH PRESSURE COOLANT INJECTION STEAM LINE RUPTURE DISCS INJURES PLANT PERSONNEL

Addressees

All holders of operating

licenses or construction

permits for nuclear power reactors.

Purpose

The U.S. Nuclear Regulatory

Commission (NRC) is issuing this information

notice to remind addressees

of the hazards associated

with steam driven coolant injection

systems such as the high pressure coolant injection (HPCI)system and the reactor core isolation

cooling (RCIC) system at BWRs and the auxiliary

feedwater

system at PWRs. It is expected that recipients

will review the information

for applicability

to their facilities

and consider actions, as appropriate, to avoid similar problems.

However, suggestions

X contained

in this information

notice are not NRC requirements;

therefore, no specific action or written response is required.Background

The purpose of HPCI steam exhaust rupture discs is to protect the HPCI turbine casing and associated

exhaust piping from an overpressure

event if the normal exhaust path to the suppression

pool becomes blocked. At Quad Cities Station, two 40.6-cm [16-inch]

stainless

steel discs are installed

in series with a 6.4-cm [2.5-inch]

spacer between them to allow for a pressure sensor instrumentation

line. The pressure sensor, while serving no control function, actuates an alarm in the control room at 68.9 kPa [10 psig] to alert the operators

that the inner disc is leaking. The normal range of the HPCI exhaust steam pressure is 172 to 207 kPa [25 to 30 psig].- The HPCI high exhaust pressure turbine trip setpoint is 689 kPa [100 psig] and is sensed by pressure sensors located downstream

from where the section of piping containing

the rupture discs branches off from the exhaust piping. The section of piping containing

the rupture discs is mounted vertically

over the turbine exhaust and vents directly to the HPCI room. Pressure greater than 1034 kPa [150 psig] in the exhaust line will cause the inner disc to rupture and impact the outer disc, releasing

steam into the HPCI room.Description

of Circumstances

During a quarterly

inservice

test of the HPCI pump at the Commonwealth

Edison Quad Cities Station, Unit 1, on June 9, 1993, the exhaust steam line rupture 9308100248 F QrRi

IN 93-67 August 16, 1993 discs burst, releasing

steam into the HPCI room, burning, and slightly contaminating, five workers. The rupture discs burst within one second after the turbine was started. Fire doors between the Unit 1 and Unit 2 HPCI rooms were blown off their hinges into the Unit 2 HPCI room. Both sets of double doors that are part of the secondary

containment

boundary were also blown open. The floor latch on the inner containment

door was bent; the outer doors were also slightly damaged, but were repaired, closed and sealed approximately

35 minutes after the event. The steam release was terminated

by automatic isolation

of the steam supply line on high HPCI turbine area temperature

about 20 seconds into the event.Discussion

Upon investigating

the event, the licensee determined

that water had accumulated

in the turbine casing because the drain system level switches for the Unit 1 HPCI system had failed. In April 1992, the licensee performed

a reliability-centered

maintenance

study which recommended

the level switches be included in the preventive

maintenance

program but the recommendation

had not been acted on at the time of the event. The Unit 2 HPCI drain system level switches were also found to be inoperable.

The slug of water created during the HPCI turbine roll passed from the turbine casing to the vertical exhaust line and compressed

the air in the 40.6 cm[16 inch] line containing

the rupture discs. The resulting

pressure pulse caused the inner rupture disc to burst, which impacted the outer disc as designed and caused it to burst as well. The exhaust line pressure sensors, located in the horizontal

61 cm [24 inch] exhaust line that tees off from the vertical 40.6 cm [16 inch] rupture disc line, did not detect a high pressure (see Figure 1). The pressure switches were within tolerance

and should have immediately

isolated the steam supply upon sensing a high exhaust pressure before the rupture discs burst. The fact that a high exhaust line pressure was not detected indicates

two possible causes for the disc rupture. Either the inner rupture disc was degraded and burst at lower-than-design

pressure, or the pressure pulse actually exceeded the design pressure and caused the disc to burst, relieving

the exhaust line pressure before the downstream

pressure sensors detected a high pressure condition.

While inspection

of the rupture discs did not reveal any degradation

from corrosion

or aging, the vendor, Black Sivalls & Bryson, Inc, stated that the discs are warranted

for one year of service under normal conditions.

The HPCI and RCIC rupture discs at Quad Cities Station had been in service for 20 years and were not part of any scheduled

inspection

or preventive

maintenance

program. When consulted

about the event, the vendor advised against using the spare discs in the plant storeroom

because they were purchased

at the same time as the failed discs. The licensee later replaced the failed discs with new units. Before this event, the licensee recently replaced a HPCI rupture disc during a refueling

outage at the Dresden Station, a plant similar to Quad Cities, after finding a crack in the disc during an inspection.

The rupture discs were inspected

at the Dresden station as part of an enhancement

to the preventive

maintenance

program that was recommended

by a reliability-centered

analysis.

I I IN 93-67 August 16, 1993 The steam injured five workers, four of whom were participating

in the HPCI pump surveillance

test. The fifth, and m6st severely.

injured worker was a health physics technician

in the room on routine rounds, who was not aware of the danger posed by the surveillance

test. The test procedure

contained

no specific guidance on room occupancy.

Interviews

with the workers revealed that they had performed

the surveillance

in the past and were familiar with the process. This familiarity

may have led to a relaxed attitude toward personal safety. The workers stated that during previous surveillances

they sometimes

evacuated

the room before rolling the turbine, or stood near the doors to be ready to escape. The licensee made no routine announcement

over the plant paging system to alert plant personnel

before the HPCI-turbine

start, and the workers were not prepared for the turbine to start.A lack of constant communication

between the workersand

the control room may have contributed

to the personnel

injuries.

If a control room operator had been in contact with the workers in the HPCI room during the turbine roll, the workers would have been aware of the impending

turbine start and, after start, the steam supply might have been manually-isolated

or the turbine manually tripped before the automatic

isolation

caused by the high area temperatureoin

the HPCI room.When the Unit 1 HPCI rupture disc failure caused the fire doors to be blown off their hinges and into the Unit 2 HPCI room, one of the doors impacted a pipe hanger in the room and moved it 5.1 centimeters

[2 inches]. If the steam release had resulted from a high energy line break from the inlet side of the HPCI steam line instead of the exhaust line, the damage to the Unit 2 HPCI system could have been more severe. While high energy line breaks have been analyzed for safety systems at all plants, the doors to rooms containing

high energy steam lines may not have been included in the analysis.

For example, at Duane Arnold Energy Center, the licensee discovered

that while the HPCI and RCIC rooms were qualified

for pressures

of 26.2 kPa [3.8 psig], the doors between these rooms and the reactor building would yield at 6.9 kPa [1 psig].The licensee for the Quad Cities Station will implement

a preventive

maintenance

schedule for both the HPCI and RCIC rupture discs and the level switches.

The licensee will review the surveillance

test procedure

and evaluate the missile hazard created by the fire doors. The licensee replaced the rupture discs for the Unit 2 HPCI and RCIC systems with new ones after the event at Unit 1 and is considering

burst testing the removed discs to determine

if they are degraded.

IN 93-67 August 16, 1993 This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact the technical

contact listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grim s, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Clark Vanderniet, RIII (708) 790-5594 David Skeen, NRR (301) 504-1174 Attachments:

1. Figure 1, "Simplified

Layout of Quad Cities Station HPCI Turbine Exhaust Steam Line" 2. List of Recently Issued NRC Information

Notices

Cq~0cr cO Cd) h r-4 0\TO SUPPRESSION

POOL 1 OUTER RUPTURE DISC _____CLOSABLE CHECK CHECK VALVE VALVE I INNER RUPTURE DISC[1 In]2 40.6 cm[16 in]VENT TO HPCI ROOM STEAM INLET LINE FROM "B" MAIN STEAM LINE LOCKED OPEN I I I I I RX BLDG I I I I 50.8 cm[20 In]61 cm[24 In]HPCI ROOM 25 cm[10 In]D NOTES: 1. PRESSURE SWITCH ACTUATES ALARM IN CONTROL ROOM WHEN PRESSURE BETWEEN THE INNER RUPTURE DISC AND OUTER RUPTURE DISC IS GREATER THAN 68.9 kPa [10 psig]. ALARM IS FOR INNER RUPTURE DISC LEAK DETECTION.

2. REDUNDANT

PRESSURE SWITCHES IN EXHAUST STEAM LINE TRIP THE HPCI TURBINE IF PRESSURE IS GREATER THAN 689 kPa [100 psig].3. RUPTURE DISC MAXIMUM DESIGN BURST PRESSURE IS 1034 kPa [150 psig].Figure 1 -Simplified

Layout of Quad Cities Station HPCI Turbine Exhaust Steam Line

Attachment

2 IN 93-67 August 16, 1993 LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Information

Date of Notice No. Subject Issuance Issued to 93-66 93-65 93-64 93-63 93-62 93-61 93-60 93-59 93-58 Switchover

to Hot-Leg Injection

Following A Loss-of-Coolant

Accident in Pres-surized Water Reactors Reactor Trips Caused by Breaker Testing with Fault Protection

Bypassed Periodic Testing and Preventive

Maintenance

of Molded Case Circuit Breakers Improper Use of Soluble Weld Purge Dam Material Thermal Stratification

of Water in BWR Reactor Vessels Excessive

Reactor Coolant Leakage Following

A Seal Failure in A Reactor Coolant Pump or Reactor Recirculation

Pump Reporting

Fuel Cycle and Materials

Events to the NRC Operations

Center Unexpected

Opening of Both Doors in An Airlock Nonconservatism

in Low-Temperature

Overpressure

Protection

for Pressurized- Water Reactors 08/16/93 08/13/93-08/12/93 08/11/93 08/10/93 08/09/93 08/04/93 07/26/93 07/26/93 All holders of OLs or CPs for pressurized

water reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for boiling water reactors.All holders of OLs or CPs for nuclear power reactors.All fuel cycle and materials licensees.

All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for pressurized-water

reactors.OL = Operating

License CP = Construction

Permit

l--IN 93-67 August 16, 1993 This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact the technical

contact listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.orig /s/'d by CIGrimes/for

Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts: Clark Vanderniet, RIII (708) 790-5594 David Skeen, NRR (301) 504-1174 Attachments:

1. Figure 1, "Simplified

Layout of Quad Cities Station HPCI Turbine Exhaust Steam Line" 2. List of Recently Issued NRC Information

Notices*SEE PREVIOUS CONCURRENCE.

OFC *OEAB:DORS

• TECH:ED *OGCB:DORS

• DRS:R-III

NAME DSkeen JMain PWen CVanderniet

DATE 07/08/93 , 07/08/93 07/14/93 07/14/93 OFC *C:DRS:R-III

• SC:OEAB:DORS

• C/OEAB/DORS

• C:SPLB:DSSA

NAME GWright I RDennig AEChaffee

CEMcCracken

DATE [ 07/14/93 1 07/15/93 07/15/93 ]07/16/93 I__ _ i OFC*D:DSSA*C/OGCB:DORS

D/DORS A^r NAME AThadani GMarcus BGrimes t DATE 07/24/93 07/29/93 0,S/\o/93 V[OFFICIAL

RECORD COPY]DOCUMENT NAME: 93-67.IN

\-IN 93-XX July XX, 1993 This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact the technical

contact listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts:

Clark Vanderniet, RIII (708) 790-5594 David (301)Skeen, NRR 504-1174 Attachment:

List of Recently Issued NRC Information

Notices*SEE PREVIOUS CONCURRENCE.

• D:DSSA AThadani 07/24/93 OFC *OEAB:DORS

• TECH:ED *OGCB:DORS

• DRS:R-III

NAME DSkeen JMain PWen CVanderniet

DATE J 07/08/93 07/08/93 07/14/93 07/14/93 OFC *C:DRS:R-III

• SC:OEAB:DORS

• C/OEAB/DORS

• C:SPLB:DSSA

NAME GWright RDennig AEChaffee

CEMcCracken

DATE J 07/14/93 07/15/93 107/15/93 J07/16/93.Y.OFC C/OGCB:DORS

D/DORS NAME GMarcus ifM BGrimes T DATE 07/.9/93 07/ /93[OFFICIAL

RECORD COPY]DOCUMENT NAME: IN93 XX.QC1 IN 93-XX July xx, 1993 This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts: Clark Vanderniet, R-III (708) 790-5594 David Skeen, NRR (301) 504-1174 Attachment:

List of Recently Issued NRC Information

Notices*SEE PREVIOUS CONCURRENCE

OFFICE *OEAB:DORS

• TECH:ED *OGCB:DORS

• DRS:R-III

NAME DSkeen JMain l PWen CVanderniet

DATE 07/08/93 07/08/93 07/14/93 07/14/93 1'I*C:DRS:RIII

• SC:OEAB:DORS

• C:OEAB:DORS

C:SPLBAS*

D: DSS 3q %GWright RDenning AChaffee CEMcCracken

ACThadani 07/14/93 [07/15/93

07/15/93 -07/2/f93

07/2A/93 C:OGCB:DORS

D: DORS GHMarcus BKGrimes 07/ /93 07/ /93 DOCUMENT NAME: QCHPCIIN.WEN

C 5 G-4J -z--l -2'J 4 3-- -k k- 9 C J-

IN 93-XX July xx, 1993 This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts: Clark (708)Vanderniet, R-III 790-5594 David Skeen, NRR (301) 504-1174 Attachment:

List of Recently Issued NRC Information

Notices*SEE PREVIOUS CONCURRENCE

OFFICE *OEAB:DORS

• TECH:ED *OGCB:DORS

• DRS:R-III

NAME DSkeen JMain PWen CVanderniet

DATE 07/08/93 07/08/93 07 114/93 07/14/93 L, _, I_,__ _ .., __ ...I_ I -*C:DRS:RIII

S ODORS EAB:DORS C:SPLB:DSSA

D:DSSA GWright R enn afaf' afee CEMcCracken

ACThadani 07/14/93 [ 3 07/j</93 07/ /93 07/ /93 C:OGCB:DORS

D:DORS GHMarcus BKGrimes 07/ /93 07/ /93 0 DOCUMENT NAME: QCHPCIIN.WEN

-E7/14/93 12:53 ?03 787905538417463837 P. 0', This infi you have the tech Roactor IN 93-XX July xx. 1993 Irmation notice requires no specific action or written response.

It any questions

about the information

in this noticet please contact lcal contmct listed below or the appropriate

Office of Nuclear r.gulmtion (NRR) project manager.Brian K. Grimes, Director Division of sOrating RGOM Support Office of Nuclear Reactor Regulation

Technic~l

contacts Clark Vanderniet, R-II1 (708) 790-5594 Oavid Skeen NRR (301) 604-1174 Attach 4 nt: List of Recently Issued NRC Information

Notices/._ _ *,,1'SEL PR -.IUUb 6UNCUUMM6C, OFFIC D _ *TECH:,ED

-I _ I R NAME _ JGnMain PI_. ., I -- '^A j" IR na jai4 I 7/1k01.%0J//Y//93 I1 UATI I uJ 1 b I W ._ I I nF&-flIA I C:PBDS :ISS I ----.n J T TV cr P. rAn

• Motw rn r nAs WDgR I C.SPLB*DSSA

D :DSSA_I Ch ouf I 1NNI I I I;rn n I= -- 1 --.-. -T II 1 A tn"^"4^" I ji 1%V, fam rEIaCracken

ACThadani

_1 OI-lqn 0, 7/ R/9M3..~07~11 9 93 07/ /93 -- 107/ /193 -IQl l 193 107/ /93--:_ _r _r.nnr 'f lRS D:DORS us BK rimes-.. ..- _ L4Y.IIuL)OCUME NA ML: QUMrLun.w~J'

14 JUL 93 B: 5u LETd lN11 211HM DUN 411 b0S T ,z ES:90 t 5os->X-L0 LM1 b0S IQ£

J\1 IN 93-XX July xx, 1993 This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact the technical

contact listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Director Division of Operating

Reactor Support Office of Nuclear Reactor Regulation

Technical

contacts: Clark (708)Vanderniet, R-III 790-5594 David Skeen, NRR (301) 504-1174 Attachment:

List of Recently Issued NRC Information

Notices*SEE PREVIOUS CONCURRENCE

I OFFICE *OEAB:DORS

• TECH:ED _ _GC i'O W DRS:R-III NAME DSkeen JMain PWen CVanderniet

DATE 07/08/93 07/08/93 07/ W/93 07/ /93 C:DRS:RIII

SC:OEAB:DORS

C:OEAB:DORS

C:SPLB:DSSA

D:DSSA GWright RDenning AChaffee CEMcCracken

ACThadani 07/ /93 J07/ /93 07/ /93 07/ /93 07/ /93..I C:OGCB:DORS

D:DORS GHMarcus BKGrimes 07/ /93 07/ /93 DOCUMENT NAME: QCHPCIIN.WEN

I' >OFC OEAB:DORS

SC/OEAB:DORS

PUB:ADM C/OEAB:DORS

NAME DSkeen o RDennig Tech Ed T7av LY AChaffee[DATE 1 7/g/93 / /93 7/P /93 / /93 OFC OGCB:DORS

C/DRS/R-III

DRS/R-III NAME PWen GWright CVanderniet

DATE / /93 / /93 / /93 OFC TECH BRANCH CHF TECH BR C/OGCB:DORS

D/DORS NAME l GMarcus l BGrimes DATE / /93 / /93 / /93 1 / /93 l[OFFICIAL

RECORD COPY]DOCUMENT NAME: IN93 XX.QC1