Information Notice 1998-14, Undocumented Changes to Non-Power Reactor Safety System Wiring

Undocumented Changes to Non-Power Reactor Safety System Wiring

ML031050184
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	04/20/1998
From:	Roe J Office of Nuclear Reactor Regulation
To:
References
IN-98-014, NUDOCS 9804150188
Download: ML031050184 (10)

UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 April 20, 1998 NRC INFORMATION

NOTICE 98-14: UNDOCUMENTED

CHANGES TO NON-POWER REACTOR SAFETY SYSTEM WIRING

Addressees

All holders of operating

licenses or construction

permits for test and research reactors.

Purpose

The U.S. Nuclear Regulatory

Commission (NRC) is issuing this information

notice to inform addressees

of undocumented

modifications

that have occurred in the scram system wiring of two research reactors.

In the first case, the modification

in conjunction

with a switch failure resulted in the reactor being operated for a short time without any technical

specification (TS)required scrams. In the second case, because of a modification, a switch failure could have resulted in a TS required scram being disabled.

It is expected that recipients

will review the information

for applicability

to their facilities

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

However, suggestions

contained

in this information

notice are not NRC requirements;

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

of Circumstances

Oregon State Universty On the morning of February 17, 1998, the TRIGA non-power

reactor at Oregon State University (OSU) had completed

a routine 14-minute

run at 15 watts of power to perform core excess reactivity

measurements.

An attempt was made to manually scram the reactor at the end of the run using the scram button. When the manual scram button did not work, the operators

next step was to turn off power to the scram circuit using the reactor's

three-position

key switch.This switch-1s

OFF, OPERATE, and RESET positions

with a spring return between the RESET and OPERATE positions.

As the operator touched the switch, the switch moved from a position between OPERATE and RESET to the OPERATE position.

The operator then tried the manual scram button again and this time it worked.The licensee determined

that a buildup of dirt prevented

the three-position

switch from returning to the OPERATE position.

When the switch is in the RESET position, the scram bus is disabled.

This switch dates to 1967 when the original console was installed.

The switch operated properly during preoperational

testing before startup.Upon further investigation, the licensee discovered

that the wiring of the scram circuit was different

from the wiring shown in the Instrument

Maintenance

Manual provided by the reactor vndr. Fgure I shows part of the circuitry

as designed.

If the key switch is in the OPERATE D 04151-'i ureg 1D s4 ows~g- lt;)X

K>IN 98-14 April 20, 1998 position, ac power is supplied from terminal block one, terminal number four (TBI -4) through TBI-9, to TB2-3, the A3 and Al contacts of the three-position

switch, and then the console power switch. This allows transformer

four (T4) to power the rod magnets. When the key is turned to RESET, this circuit is opened and the magnet current is cut off. This prevents rod withdrawal

if the rods are down, or causes the rods to drop if they are up. This design feature prevents a single failure of the three-position

switch from disabling

the scram circuits.

In the RESET position, power is supplied to the scram reset relays (K19, K20, and K24), which reset the scram relays (only one scram relay, K12, is shown). If the key switch sticks in the RESET position, the scram relay will continued

to be energized

by the reset relay even if a scram signal occurs. This is not a problem because the power would already be cut off to the magnets.Figure 2 shows the wiring as found in the OSU console. The wiring that was between TB1-9 and TB2-3 in the "as designed" circuit was between TBI-9 and TBIO-10 in the OSU console.As a result, there is power to the magnets when the switch is in the RESET or OPERATE position.The licensee concluded

that the location of the jumper was probably modified during initial installation

of the reactor console in 1967. This modification

was probably done to provide power to the *B deck 3 on the three-position

switch to power REACTOR ON lights.The licensee took a number of corrective

actions. The three-position

switch was removed, cleaned, relubricated, and reinstalled

in the console. The reactor console wiring was restored to its as-designed

condition.

The wiring in the scram circuitry

and in other non-scram-related

circuits was checked physically

and electronically

to demonstrate

that the wiring in the console is as designed.

The reactor startup procedure

was rewritten

to test that the magnet power is cut off when the three-position

switch is placed in the RESET position.

The reactor console was subject to routine startup checks and the semiannual

console check procedure.

The reactor vendor was contacted

to obtain checkout procedures

to confirm that all suggested surveillances

are done before reactor operation.

Texas A&M Universiy OSU quickly placed information

about the failure to scram on the Organization

of Test, Researth and Training Reactors (TRTR) list server. As a result, the staff at the Texas A&M University

N&clear Science Center checked the logic diagrams for its TRIGA research reactor and determined

that its reactor could not fail to scram. The Texas A&M console differs from the one at OSU in that there is no master reset equivalence

to the three-position

switch. Three of the scrams have push-button

spring-returned

switches that clear the locked-in

alarm on the console and allow the scram relay coil to be reenergized

if the signal is clear.The licensee also tested the circuit and determined

that each of the three scrams associated

with these switches could be defeated by holding its switch down in the RESET position (this simulated

a switch failure).

In this case, the failure of a single switch could prevent an individual

scram signal but would have not disabled all scrams. The licensee then checked the wiring diagrams for the console and discovered

that the wiring of the console matched the wiring diagrams.

The RESET switches were wired in parallel with the normally closed scram contacts.This wiring maintained

power to the magnets through one parallel path if the switch was

IN 9S*14 April 20, 1998 depressed, even if a scram contact opened in the other parallel path. The switches should have been wired in series. The licensee cannot determine

when the console was wired this way, but notes that the console underwent

a major upgrade in 1968. The logic diagram, drawn in 1976, which differs from the wiring diagram and the as-wired console, appears to have been based on system knowledge

of how it should be configured

rather than on the actual configuration.

To correct this situation, the licensee changed the wiring to put the RESET switch in series with the protective

action contacts, physically

verified console wiring for scram circuits, identified

various failure modes, and tested the console for proper operation.

Discussion

The circumstances

described

above demonstrate

the importance

of controlling

modifications, ensuring that all of the consequences

of a modification

are carefully

considered, and ensuring that design features in the scram circuitry

perform as designed.

Careful reviews of modifications

through the safety review process can be an effective

method to help to ensure that unintended

deleterious

effects from modifications

do not occur. The identification

of safety system design features could lead to surveillances

or tests that could prevent the occurrence

of similar problems.

The staff noted that many licensees

contacted

the NRC to discuss the results of testing performed

on consoles because of the information

placed on the TRTR listed server by OSU.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.Jack Roe, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contact: Alexander

Adams, Jr., NRR 301-415-1127.E-mail: axa@nrc.gov

Attachments:

1. Figure 1, *Reactor Operate Circuit, As-Designed" 2. Figure 2, Reactor Operate Circuit -As Found" 3. List of Recently Issued NRC Information

Notices-L

vD C Em DOCUMENT NAME: G:WVERN\OSUSCRAM.INF

Tech Editor concurred

on 3126/98 To receive a copy of this document, indicate in the box C=Copy wlo attachmentlenclosure

E=Copy with attachmentfenclosure

N = NIcopy OFFICE PDND (A)D:PDND

C:PECB (A)D:DRPIV\S

A NAME AAdams* MMendonca*

JStolz* JRoe*[DATE 03/30198 03/30/98 04/06/98 04/13/98 5'OFFICIAL RECORD COPY

P6-3 5 P22-1 0 TB10 Switched AC (H)T P2 f6 2 T T1 Bi B36P22-l1 T910 4 T4 50 Operate Permissive

Jumper 1 3 A .34P3-21 TB2 1 4TB` P3-202 CBB1l A4 >3 P5-4 AC (N) *OFF 0J5) *OPERATE (*RESET Part of Console Key Switch TBl 0 dAC (N)External Scram AC (N)-. (Kl12 K19 K20 K24 Kl2 l H tK1 6-7 'Switched AC (H)Fiaure I. Reactor OnprAt0 Circiuit.

Aq-dpeinnadr

..I-- -..--. -V-- --- -..-- .-, --- --- .U.-

Si9 P6-35 P22-10 TB10 TB10 Si "KSwitched

AC (H)82 AC (N) TB1 POWER OR P6-36 P22-11 TB10 E3 T4 P5-1 A2 .341 P3(2 T82 P3-0 Cal 8L P5-4 AC (N) f*OF*OPERATE* RESET Part of Console Key Switch (TB1 0 SIAC (N)Exterral Scram NO AC (N)0- -- 9X6-7 l_______ Switched AC (H) f5B Ftc Figr 0. Reco prt 0cft- A Fud

.I Attachment

3 IN 98-14 April20, 1998 LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Information

Date of Notice No. Subject Issuance Issued to 98-13 Post-Refueling

Outage Reactor 4120/98 All holders of operating

licenses Pressure Vessel Leak Testing Before Core Criticality

for nuclear power reactors except those that have permanently

ceased operations

and have certified

that fuel has been permanently

removed from the reactor vessel 98-12 9&-1 1 Licensees'

Responsibilities

Regarding

Reporting

and Follow-up Requirements

for Nuclear-Powered

Pacemakers

Cracking of Reactor Vessel Internal Baffle Former Bolts in Foreign Plants 4/3/98 3/25/98 All U.S. Nuclear Regulatory

Commission

nuclear pacemaker licensees All holders of operating

licensing for pressurized-water

reactors (PWRs) except those who have ceased operation

and have certified

that fuel has been permanently

removed from the reactor vessel.95-52, Supp. 1 Fire Endurance

Test Results for Electrical

Raceway Fire Barrier Systems Constructed

From 3M Company Interam-ire Barrier Materials 3/17/98 All holders of operating licenses for nuclear power reactors except those who have permanently

ceased operation

and have certified

that fuel has been permanently

removed from the reactor vessel.98-10 98-09 Probable Misadministrations

Occurring

During Intravascular

Brachytherapy

With The Novoste Beta-Cath

System Collapse Of An Isocam II Dual-Headed

Nuclear Medicine Gamma Camera 3/9/98 3/5/98 All Medical Licensees All Medical Licensees OL = Operating

License CP = Construction

Permit

• KIN ?-14 April 20, 1998 depressed, even if a scram contact opened in the other parallel path. The switches should have been wired in series. The licensee cannot determine

when the console was wired this way, but notes that the console underwent

a major upgrade in 1968. The logic diagram, drawn in 1976, which differs from the wiring diagram and the as-wired console, appears to have been based on system knowledge

of how it should be configured

rather than on the actual configuration.

To correct this situation, the licensee changed the wiring to put the RESET switch in series with the protective

action contacts, physically

verified console wiring for scram circuits, identified

various failure modes, and tested the console for proper operation.

Discussion

The circumstances

described

above demonstrate

the importance

of controlling

modifications, ensuring that all of the consequences

of a modification

are carefully

considered, and ensuring that design features in the scram circuitry

perform as designed.

Careful reviews of modifications

through the safety review process can be an effective

method to help to ensure that unintended

deleterious

effects from modifications

do not occur. The identification

of safety system design features could lead to surveillances

or tests that could prevent the occurrence

of similar problems.

The staff noted that many licensees

contacted

the NRC to discuss the results of testing performed

on consoles because of the information

placed on the TRTR listed server by OSU.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.orig /sfd by D. B. Matthews FOR Jack Roe, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contact: Alexander

Adams, Jr., NRR 301-415-1127 E-mail: axa~nrc.gov

Attachments:

1. Figure 1, OReactor Operate Circuit, As-Designed'

2. Figure 2, uReactor Operate Circuit -As Found" 3. List of Recently Issued NRC Information

Notices DOCUMENT NAME: G:WVERN\OSUSCRAM.INF

Tech Editor concurred

on 3/26198 To receive a copy of this document indicate In the box C=Copy wlo attachmentenclosure

E=Copy with attachmentlenclosure

N = No copy OFFICE PDND (A)D:PDND

I C:PECB Il (A)D:DRPM

Il NAME AAdams* MMendonca*

JStolz* JRoe*lDATE _ 03/30/98 03/30/98 04106198 j 04/13/98 OFFICIAL RECORD COPY

-- INbe14 April 20, 1998 depressed, even if a scram contact opened in the other parallel path. The switches should have been wired in series. The licensee cannot determine

when the console was wired this way, but notes that the console underwent

a major upgrade in 1968. The logic diagram, drawn in 1976, which differs from the wiring diagram and the as-wired console, appears to have been based on system knowledge

of how it should be configured

rather than on the actual configuration.

To correct this situation, the licensee changed the wiring to put the RESET switch in series with the protective

action contacts, physically

verified console wiring for scram circuits,.identified

various failure modes, and tested the console for proper operation.

Discussion

The circumstances

described

above demonstrate

the importance

of controlling

modifications, ensuring that all of the consequences

of a modification

are carefully

considered, and ensuring that design features in the scram circuitry

perform as designed.

Careful reviews of modifications

through the safety review process can be an effective

method to help to ensure that unintended

deleterious

effects from modifications

do not occur. The identification

of safety system design features could lead to surveillances

or tests that could prevent the occurrence

of similar problems.

The staff noted that many licensees

contacted

the NRC to discuss the results of testing performed

on consoles because of the information

placed on the TRTR listed server byOSU.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.Jack Roe, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contact: Alexander

Adams, Jr., NRR 301-415-1127 E-mail: axa@nrc.gov

Attachments:

1. Figure 1, uReactor Operate Circuit, As-Designed" 2. Figure 2, "Reactor Operate Circuit -As Found" 3. List of Recently Issued NRC Information

Notices DOCUMENT NAME: G:WVERNOSUSCRAM.INF

Tech Editor concurred

on 3/26198 To receive a copy of this document, indicate in the box C=Copy wlo attachmentlenclosure

E=Copy with attachmentenclosure

N = Nlcopy I OFFICE PDND I (A)D:PDND

l C:PECB I (A)D:DRP NAME AAdams* MMendonca*

JStoz* JRoe*l DATE 03/30/98 03/30/98 04/06/98 04/13/98 OFFICIAL RECORD COPY

IN' XX .K ApexL 1998 (this simulated

a switch failure).

In this case, the failure of a single switch could preve an individual

scram signal but would have not disabled all scrams. The licensee then ecked the wiring diagrams for the console and discovered

that the wiring of the console moed the wiring diagrams.

The RESET switches were wired in parallel with the normall y-losed scram contacts.

This wiring maintained

power to the magnets through one paralle ath if the switch was depressed, even if a scram contact opened in the other parallel pathThe switches should have been wired in series. The licensee cannot determine

when the sole was wired this way, but notes that the console underwent

a major upgrade in 1968. e logic diagram, drawn in 1976, which differs from the wiring diagram and the as-wired co sole, appears to have been based on system knowledge

of how i should be configured

rat r than on the actual configuration.

To correct this situation, the licensee changed the wiring put the RESET switch in series with the protective

action contacts, physically

verified conso wiring for scram circuits, identified

various failure modes, and tested the console for probr operation.

Discussion

The circumstances

described

above demon ate the importance

of controlling

modifications, ensuring that all of the consequences

of a odification

are carefully

considered, and ensuring that design features in the scram circuit perform as designed.

Careful reviews of modifications

through the safety revie process can be an effective

method to help to ensure that unintended

deleterious

effects f m modifications

do not occur. The Identification

of safety system design features could lead o surveillances

or tests that could prevent the occurrence

of similar problems.

The staff note that many licensees

contacted

the NRC to discuss the results of testing performed

on consols because of the information

placed on the TRTR listed server by OSU.This information

notice r uires no specific action or written response.

If you have any questions

about the inf ation in this notice, please contact the technical

contact listed below.Jack Roe, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

c ctac: Alexander

Adams, Jr., NRR 301-415-1127 E-mail: axaenrc.gov

Attac ent: List of Recently Issued NRC Information

Notices DT e MENT NAME: G:WVERN\OSUSCRAM.INF

To receive a copy f this document.

indicate In the box C=Copy w/o attachmeE=Copy

with co OFFICE PDND I _ (A)D:PDND

l C:PE'CB (A)D:DR hl1 I NAME AAdams* MMendonca*

iQStolz JRoe Jk DATE 03/30198 03/30/98 g 4 /j3198 OFFICIAL RECORD COPY a-) .

IN'- XX_ ApiV..x, 1998 switch failure).

The licensee then checked the wiring diagrams for the console and discovered

that the wiring of the console matched the wiring diagrams.

In this case, the failure of a single switch could prevent an individual

scram signal but would have not disabled all scrams. The RESET switches were wired in parallel with the normally closed scram contacts.

This wiring maintained

power to the magnets through one parallel path if the switch was depressed, even if a scram contact opened in the other parallel path. The switches should have been wired in series. The licensee cannot determine

when the console was wired this way, but notes that the console underwent

a major upgrade in 1968. The logic diagram, drawn in 1976, which differs from the wiring diagram and the as-wired console, appears to have been based on system knowledge

of how it should be configured

rather than on the actual configuration.

To correct this situation, the licensee changed the wiring to put the RESET switch in series with the protective

action contacts, physically

verified console wiring for scram circuits, identified

various failure modes, and tested the console for proper operation.

Discussion

The circumstances

described

above demonstrate

the Importance

of controlling

modifications, ensuring that all of the consequences

of a modification

are carefully

considered, and ensuring that design features in the scram circuitry

perform as designed.

Careful reviews of modifications

through the safety review process can be an effective

method to help to ensure that unintended

deleterious

effects from modifications

do not occur. The identification

of safety system design features could lead to surveillances

or tests that could prevent the occurrence

of similar problems.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.Jack Roe, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contact: Alexander

Adams, Jr., NRR 301-415-1127 E-mail: axa@nrc.gov

Attachment:

List of Recently Issued NRC Information

Notices DOCUMENT NAME: G:WVERN\OSUSCRAM.INF

To receive a copy of this document, indicate in the box C=Copy wlo attachment/endosure

E=Copy with attachment/enclosure

N = No copy OFFICE PDND I l (A)D:PDND

l l C:PECB (A)D:DRPM

Il NAME AAdams OA l MMendonca

L4/) T JStolz JRoe DATE 1 031/)/98 l 0313)198 1 03/ /98 7 03/ /98 OFFICIAL RECORD COPY