Information Notice 1986-63, Loss of Safety Injection Capability

Loss of Safety Injection Capability

ML031250058
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, 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, Skagit, Marble Hill, Crane
Issue date:	08/06/1986
From:	Jordan E NRC/IE
To:
References
IN-86-063, NUDOCS 8608010289
Download: ML031250058 (4)

SSINS No.: 6835 IN 86-63 UNITED STATES

R E

WIthE D

NUCLEAR REGULATORY COMMISSION

ie rt D.

Nuear

OFFICE OF INSPECTION AND ENFORCEMENT

VIC

Pres1e

Nuc1ear

WASHINGTON, DC 20555 Ru

G

To:

1986

August 6, 1986

IE INFORMATION NOTICE NO. 86-63:

Addressees

All pressurized water nuclear power reactor facilities holding an operating

license or a construction permit.

Purpose

This notice is to alert recipients to a potentially significant problem per- taining to the loss of safety injection (SI) capability as a result of

common-mode failure of SI pumps from crystallization of boric acid. The NRC

expects that recipients will review this notice for applicability to their

facilities and consider actions, if appropriate, to preclude a similar problem

occurring at their facilities.

However, suggestions contained in this notice

do not constitute NRC requirements; therefore, no specific action or written

response is required.

Related Documents:

AEOD Engineering Evaluation Report E606:

'Loss of Safety Injection Capability

at Indian Point Unit 2," May 1986.

NRR Generic Letter 85-16:

"High Boron Concentrations," August 23, 1985.

NRC "Report to Congress on Abnormal Occurrences," NUREG-0090, Vol. 8, No. 2, November 1985.

Description of Circumstances

On December 28, 1984, during operations to top off the ECCS accumulators, the

licensee at Indian Point Unit 2 observed discharge pressure to two SI pumps to

drop from 1100 psig and 1500 psig, respectively, to about 700 psig corresponding

to accumulator pressure. These pumps were secured from operation. The third SI

pump could not be manually started.

The licensee declared all the safety

injection (SI) pumps inoperable and manually tripped the reactor.

The

malfunction of the pumps was apparently caused by boric acid crystallization

blocking pump suction and by possible gas binding of the pumps.

Two parallel, leaky valves in the discharge line of the boron injection tank

(BIT) enabled highly concentrated boric acid to flow through the low pressure

Copies to: Withers, Yundt, Lentsch, Orser, Steele, E. Burton, E. Jordan, A. Holm, LIS,

C. A. Olmstead, S. Hoag, S. Sautter, R. Johnson, TNP:GOV REL F:NRC CHRONO,

TNP GOV REL F:NRC IE Information Notice 86-63 PGE Action - None Required "Completed -

BIT Removed

See License Amendment 103"

A - /

- '

0

IN 86-63 August 5, 1986 discharge line (SI pump suction) and to precipitate in the pumps, which were

not heat traced. Degassing of the nitrogen cover gas dissolved in the boric

acid solution is believed to be one of the likely sources of gas found in the

pumps.

On May 10, 1974, a precursor to this event took place at Indian Point 2. In

that event, two of the three SI pumps were rendered inoperable as a result of

boric acid crystallization.

No gas was noted in the pumps at that time.

On June 1, 1984, while in cold shutdown, the licensee at San Onofre Unit 1 found the two boric acid flow paths required by the plant's Technical Specifi- cations to be blocked.

The blockage was caused by crystallization of boric

acid between the boric acid storage tank (BAST) and the charging pumps.

There

are two parallel lines, one having a transfer pump and the other a boric acid

injection pump.

Both were blocked.

The operators were using highly concen- trated boric acid from the BAST to rapidly make up to the refueling water

storage tank (RWST) but failed to monitor concentration and solubility.

Viable

alternate flow paths were established by shifting the charging pump suction to

the RWST and by using a manual bypass valve for the transfer pump.

Discussion:

These events demonstrate the potential for losing emergency safety injection

capability by common-mode failure resulting from either boric acid crystalliza- tion or gas binding of the pumps. As to the gas binding possibility in the

December 1984 event at Indian Point 2, the licensee studied the possible sources

of gas and concluded that the probable effect of gas evolution on pump

performance would be minor.

Originally in Westinghouse ( plants, the addition of highly concentrated

boric acid solution (20,000 ppm) to the reactor coolant system (RCS) following

a design-basis main steam line break (MSLB) was intended to compensate for the

addition of positive reactivity to the core by the sudden cooling of the RCS.

In most W plants, the BIT (or equivalent) is located downstream of the SI

pumps. Dn an SI signal, the pumps inject the BIT contents into the RCS,

provided the RCS pressure is less than the SI system shutoff pressure.

Indian

Point Unit 2 is among the few W PWRs that has the BIT upstream of the SI pumps.

Other plants with a source of boric acid similarly located include San Onofre

1, Haddam Neck, Yankee Rowe, Point Beach 1 and 2, Prairie Island 1 and 2, Kewaunee, and Ginna.

Of these plants, San Onofre 1, Haddam Neck, and Yankee

Rowe use typically 2,000 ppm boric acid from the RWST for SI.

Indian Point 2

uses a 20,000 ppm solution from the BIT, while Point Beach 1 and 2, Prairie

Island 1 and 2, Kewaunee, and Ginna use a 20,000 ppm solution from the BAST for

SI.

Recent evaluations of the design-basis MSLB accidents in some W PWRs have

revealed excessive conservatism regarding boric acid requirements. In some

cases, it was shown that the requirements of 10 CFR 100 would not be exceeded

if the BIT were eliminated or if the boric acid concentration were reduced.

Following the Indian Point 2 event on December 28, 1984, NRR sent Generic

IN 86-63 August 5, 1986 Letter 85-16 to all licensees of W plants to encourage them to reevaluate their

MSLB analysis and the need for the BIT.

So far, in addition to Indian Point 2, at least the following plants have received NRR approval for removal of their

.BIT and/or for modifying technical specification requirements that would allow

operation with reduced boric acid concentrations:

Turkey Point 3 and 4

Harris 1

Surry 1 and 2

Beaver Valley 1 South Texas

McGuire 1 (McGuire 2 was licensed without a BIT)

Catawba 1 and 2

Callaway

Farley 1 and 2

Trojan

For those plants that are still required to provide high boric acid concentra- tions for SI, plant-specific procedures normally provide for flushing the SI

system after every SI actuation to prevent boric acid precipitation in the

piping and for periodic sampling of the SI system.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact the Regional

Administrator of the appropriate regional office or this office.

Director

Divis fn of Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

Technical Contacts:

Vern Hodge, IE

301-492-7275

Raji Tripathi, AEOD

301-492-4435 Attachment:

List of Recently Issued IE Information Notices

• 1

Attachment 1

IN 86-63

August 5, 1986

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issue

Issued to

86-62

86-61

86-60

Potential Problems In West- inghouse Molded Case Circuit

Breakers Equipped With A

Shunt Trip

Failure Of Auxiliary Feed- water Manual Isolated Valve

Unanalyzed Post-LOCA Release

Paths

7/31/86

7/28/86

7/28/86

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

a CP

All power reactor

facilities holding

an OL or CP

86-31 K~

Sup. 1

Unauthorized Transfer And

Loss Of Control Of Industrial

Nuclear Gauges

7/14/86

All NRC general

licensees that possess

and use industrial

nuclear gauges

86-59

86-58

86-57

86-56

86-55

Increased Monitoring Of

Certain Patients With

Implanted Coratomic, Inc.

Model C-100 and C-101 Nuclear-Powered Cardiac

Pacemakers

Dropped Fuel Assembly

Operating Problems With

Solenoid Operated Valves At

Nuclear Power Plants

Reliability Of Main Steam

Safety Valves

Delayed Access To Safety-

Related Areas And Equipment

During Plant Emergencies

7/14/86

7/11/86

7/11/86

7/10/86

7/10/86

All NRC licensees

authorized to use

nuclear-powered

cardiac pacemakers

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

All PWR facilities

holding an OL or CP

All power reactor

facilities holding

an OL or CP

OL = Operating License

CP = Construction Permit