Information Notice 1986-75, Incorrect Maintenance Procedure on Traversing Incore Probe Lines

Incorrect Maintenance Procedure on Traversing Incore Probe Lines

ML031250174
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, 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, Skagit, Marble Hill
Issue date:	08/21/1986
From:	Jordan E NRC/IE
To:
References
IN-86-075, NUDOCS 8608190031
Download: ML031250174 (5)

SSINS No.: 6835 IN 86-75 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 August 21, 1986 IE INFORMATION NOTICE NO. 86-75: INCORRECT MAINTENANCE PROCEDURE ON

TRAVERSING INCORE PROBE LINES

Addressees

All nuclear power reactor facilities holding an operating license or a con- struction permit.

Purpose

This notice is to inform licensees of a potential generic problem concerning

maintenance procedures on traversing incore probe (TIP) systems having TIP

process lines that penetrate the containment. The problem arises from an

incorrect FSAR statement that the TIP lines did not have to satisfy 10 CFR 50,

Appendix A, General Design Criterion (GDC) 56. It is expected that recipients

will review the information for applicability to their facilities and consider

actions, if appropriate, to preclude similar problems from occurring at their

facilities. However, suggestions contained in this information notice do not

constitute NRC requirements; therefore, no specific action or written response

is required.

Description of Circumstances

On August 9, 1985 maintenance was performed on a Duane Arnold Energy Center

(OAEC) TIP isolation ball valve. The valve was not opening properly, thereby

preventing the TIP from being inserted. The licensee reviewed the design and

the FSAR which states in a note to Table 3.1-1: "Since the TIP system lines do

not communicate freely with the containment atmosphere and since they do not

comprise a portion of the reactor coolant pressure boundary (10 CFR 50, Appen- dix A, General Design Criteria] GDC 55 and 56 are not directly applicable to

this specific class of lines." Following this review, the licensee decided

that the isolation ball valve could be changed out with the plant on-line

because of the closed system configuration. The indexer was positioned on a

blanked off line to provide additional assurance against leakage if a TIP tube

failed in the reactor vessel. The isolation ball valve was removed and

replaced (see Figure 1).

GOC 55 addresses process lines that are part of the reactor coolant pressure

boundary and penetrate containment. GDC 56 addresses lines that connect

directly to the containment atmosphere. GDC 57 addresses lines of closed

systems that penetrate containment and are neither part of the reactor coolant

pressure boundary nor connected directly to the containment atmosphere.

8608190031

IN 86-75 August 21, 1986 In January 1986, the replacement ball valve appeared to be sticking and would

not fully open. While the licensee's Operations Review Committee was reviewing

the design before performing maintenance, it was concluded that the FSAR basis

for the previous action was not correct. Inside the primary containment, the

indexing mechanism (a revolver-like mechanism used for selecting a guide tube

leading into the reactor vessel) is mounted inside a housing equipped with a

pressure relief valve which communicates with primary containment atmosphere.

This pressure relief valve is unique in that it will open on a negative or

positive pressure inside the housing. The indexing mechanism (indexer) has a

slip fitting with the guide tubes leading to the reactor vessel. If a loss of

coolant accident occurred and the primary containment became pressurized, the

pressure relief valve would open to reduce the pressure differential across the

indexer housing and the containment atmosphere would leak past the slip fitting

into the TIP line. Under these conditions GDC 56 would apply rather than

GDC 57. With the ball valve removed for repair or replacement, primary con- tainment integrity would be compromised.

The licensee is conducting a review to determine the necessary revisions to the

Technical Specifications and FSAR. The subsequent required maintenance on the

system was conducted such that primary containment integrity was not compro- mised and post-maintenance testing included Type B and C leak testing.

Discussion:

NRC has concerns that incorrect interpretation of the design basis for TIP

systems can lead to hazardous maintenance practices. The possibility exists

for this type of maintenance error to occur on a generic basis. The FSARs for

each of several additional BWR reactors with MARK I containments were reviewed.

In those cases where the FSAR contained a section in Part 3 on meeting individ- ual general design criteria of 10 CFR 50, wording is included that is essen- tially identical to that in the FSAR of the Duane Arnold Energy Center, as

quoted above.

Plants which have committed to using ANSI/ANS 3.2-1976 (or 1982), "American

National Standard Administrative Controls and Quality Assurance for the Opera- tional Phase of Nuclear Power Plants," have committed to the requirement of

5.2.7.1 therein which states: "Maintenance shall be scheduled and planned so

as not to compromise the safety of the plant." The finding of the DAEC

Operations Review Committee is consistent with the NRC licensing practice in

defining these systems as open to the containment atmosphere, thus, opening the

system to the atmosphere outside of containment during plant operation consti- tutes a violation of containment integrity and compromises the safety of the

plant in violation of the above commitment.

In addition, if a leak from the reactor coolant system occurred or existed in

any of the TIP tubes of an indexing mechanism, opening the external line from

that mechanism for maintenance while the plant is in operation would result in

a non-isolable LOCA. Primary coolant released into the work area would result

in a hazardous steam environment and radiation exposure to maintenance person- nel in the area. The consequences of a coolant-to-tube leak are potentially

IN 86-75 August 21, 1986 An

significant unless the system is depressurized prior to performing repairs.

accident situation similar to what might occur is described in Information

Notice 84-55 Seal Table Leaks at PWRs.

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.

Edward Jordan, Director

Divisi c of Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

William F. Anderson, IE

492-4819 Attachment:

1. Figure 1

2. List of Recently Issued IE Information Notices

Attachment 1 IN 86-75 August 21, 1986

1--

BALL

VALVE

SHEAR

VALVE

r - - VALVI E

I TO PURGE SYSTEM

L--

I--- - I

I

I - I

I

L I

ELECTRICAL SIGNAL

ITO CONTROL ROO)

DUANE ARNOLD ENERGY CENTER

IOWA ELECTRIC LIGHT & POWER COMPANY

FINAL SAFETY ANALYSIS REPORT

Traversing In-Core Probe

Subsystem Block Diagram.

Attachment 2 IN 86-75 August 21, 1986 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

86-74 Reduction Of Reactor Coolant 8/20/86 All BWR facilities

Inventory Because Of Misalign- holding an OL or CP

ment Of RHR Valves

86-73 Recent Emergency Diesel 8/20/86 All power reactor

Generator Problems facilities holding

an OL or CP

86-72 Failure 17-7 PH Stainless 8/19/86 All power reactor

Steel Springs In Valcor facilities holding

Valves Due to Hydrogen an OL or CP

Embrittlement

86-71 Recent Identified Problems 8/19/86 All power reactor

With Limitorque Motor facilities holding

Operators an OL or CP

86-70 Spurious System Isolation 8/18/86 All GE BWR facilities

Caused By The Panalarm Model holding an OL or CP

86 Thermocouple Monitor

86-69 Scram Solenoid Pilot Valve 8/18/86 All BWR facilities

(SSPV) Rebuild Kit Problems holding an OL or CP

86-68 Stuck Control Rod 8/15/86 All BWR facilities

holding an OL or CP

86-67 Portable Moisture/Density 8/15/86 All NRC licensees

Gauges: Recent Incidents And authorized to possess, Common Violations Of Require- use, transport, and

ments For Use, Transportation, store sealed sources

And Storage

86-66 Potential For Failure Of 8/15/86 All power reactor

Replacement AC Coils Supplied facilities holding

By The Westinghouse Electric an OL or CP

Corporation For Use In Class

1E Motor Starters And

Contractors

OL = Operating License

CP = Construction Permit