Information Notice 1989-77, Debris in Containment Emergency Sumps and Incorrect Screen Configurations

Debris in Containment Emergency Sumps and Incorrect Screen Configurations
	ML031190009
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, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	11/21/1989
From:	Rossi C; Office of Nuclear Reactor Regulation
To:	;
References
	IN-89-077, NUDOCS 8911150013
	Download: ML031190009 (7)
	v • d • e

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 November 21, 1989 NRC INFORMATION NOTICE NO. 89-77: DEBRIS IN CONTAINMENT EMERGENCY SUMPS

AND INCORRECT SCREEN CONFIGURATIONS

Addressees

All holders of operating licenses or construction permits for pressurized water

reactors (PWRs).

Purpose

This information notice is intended to alert addressees to potential problems

resulting from inadequate housekeeping and insufficient surveillance of contain- ment emergency recirculation sumps. 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 contained in this

information notice do not constitute NRC requirements; therefore, no specific

action or written response is required.

Description-of Circumstances:

During the recovery period after a loss-of-coolant accident, following injection

of emergency coolant from the refueling water storage tank, water is collected

within the containment emergency recirculation sump to be pumped back into the

reactor coolant system. The emergency sump structures are designed to provide

for a continuous flow of water to the recirculation pumps by preventing the entry

of air or debris, thereby protecting the recirculation pumps from damage due to

loss of net positive suction head or entrained solid material. To provide guid- ance for sump designs, the NRC staff issued Regulatory Guide 1.82, "Water Sources

for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident," dated

June 1974, which was revised in November 1985. Regulatory Guide 1.82 emphasizes

the need for inservice inspection of emergency core cooling sump components, in- cluding debris interceptors, vortex suppressors, and sump outlets. The staff

also expressed the need for emergency sumps to be protected from debris in

Standard Review Plan 6,2.2 and Generic Letter 85-22, "Potential for Loss of

Post-LOCA Recirculation Capability Due to Insulation Debris Blockage.' PWR

standard technical specifications and the technical specifications of many

plants require visual inspection of the containment emergency sump and veri- fication that the suction inlets to the recirculation pumps are not restricted

by debris. Sump components, including trash racks and screens, must also be

inspected. The surveillance interval is typically 18 months.

On June 16, 1988, following a recirculation flow verification test, loose parts

and debris were found in the containment sump, the recirculation pumps, and the

suction piping of Surry Units 1 and 2. Some of the items were large enough to

' ~~0 013 Z~ >X{&

IN 89-77 November 21, 1989 have caused pump damage or flow degradation. In addition, some of the sump

screens were found to have gaps, which could have allowed additional loose

material to enter the sump. One screen was found to be missing. Following

investigation of the event by the licensee and the NRC staff, the licensee

incorporated sump surveillance requirements similar to those of PWR standard

technical specifications into their plant procedures. The NRC issued a notice

of violation and proposed imposition of a $50,000 civil penalty.

On July 8, 1989, the licensee for the Trojan facility discovered numerous items

in the containment sump. The NRC was informed of this condition on July 12, 1989.

On July 14, 1989, after containment had been closed out, an NRC inspector and the

licensee found additional debris. On July 17, 1989, the top sump screen and

portions of the inner screen were found to be missing. On July 19, 1989, the

NRC identified additional missing and damaged inner sump screens. Debris had

previously been found in the Trojan sump during a 1988 outage. In 1980, a

residual heat removal pump was jammed by a welding rod between the impeller

and the casing ring demonstrating the potential safety significance of loose

debris in the containment emergency sump. The Trojan Technical Specifications

contain periodic inspection requirements for the containment emergency sump and

sump screens. The licensee's inspection procedures for the containment emergency

sump did not have adequate inspection criteria. The NRC issued a notice of

violation and proposed imposition of a $280,000 fine for a severity level II

violation.

As a result of the problems identified at the Trojan facility, the NRC resident

inspector recently performed an inspection of the Diablo Canyon sump and sump

screens, including a comparison of the design drawing to the actual arrangement

of the sump screens. Debris was found in the Unit 1 and Unit 2 sumps, and the

sump screen arrangement on the design drawing was found to be incorrect. The

sump screens were not configured in accordance with the FSAR drawing. The Diablo

Canyon Technical Specifications contain periodic inspection requirements for the

containment emergency sump and sump screens. Initial findings indicate that

plant procedures for sump inspection were not sufficient or detailed enough

to assure adequate inspections.

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 NRR project manager.

arle . Rosts~i, ler~ector

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Walton Jensen, NRR

(301) 492-1190

Attachment: List of Recently Issued NRC Information Notices

I

Attachment

IN 89-77 November 21, 1989 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information - Date of

Notice No. Subject Issuance Issued to

89-76 Biofouling Agent: Zebra 11/21/89 All holders of OLs

Mussel or CPs for nuclear

power reactors.

89-75 Falsification of Welder 11/20/89 All holders of OLs

Qualifications for or CPs for nuclear

Contractor Employees power reactors.

89-74 Clarification of Trans- 11/7/89 All manufacturers

portation Requirements and distributors of

Applicable to Return of radiopharmaceuticals

Spent Radiopharmacy Dosages for medical use, from Users to Suppliers nuclear pharmacies, and medical licensees.

89-73 Potential Overpressurization, 11/1/89 All holders of OLs

of Low Pressure Systems or CPs for nuclear

power reactors.

89-72 Failure of Licensed Senior 10/24/89 All holders of OLs

Operators to Classify or CPs for nuclear

Emergency Events Properly. power reactors.

89-71 Diversion of the Residual 10/19/89 All holders of OLs

Heat Removal Pump Seal or CPs for nuclear

Cooling Water Flow During power reactors.

Recirculation Operation

Following a Loss-of- Coolant Accident

89-70 Possible Indications of 10/11/89 All holders of OLs

Misrepresented Vendor or CPs for nuclear

Products power reactors.

89-69 Loss of Thermal Margin 9/29/89 All holders of OLs

Caused by Channel Box or CPs for BWRS.

Bow

89-68 Evaluation of Instrument 9/25/89 All holders of OLs

Setpoints During or CPs for nuclear

Modifications power reactors.

OL = Operating License

CP = Construction Permit

,V IN 89-77 November 21, 1989 have caused pump damage or flow degradation. In addition, some of the sump