Information Notice 1991-04, Reactor Scram Following Control Rod Withdrawal Associated with Low Power Turbine Testing

Reactor Scram Following Control Rod Withdrawal Associated with Low Power Turbine Testing

ML031200008
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:	01/28/1991
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-91-004, NUDOCS 9101230299
Download: ML031200008 (6)

as ~UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 January 28, 1991 NRC INFORMATION NOTICE NO. 91-04: REACTOR SCRAM FOLLOWING CONTROL ROD

WITHDRAWAL ASSOCIATED WITH LOW POWER

TURBINE TESTING

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice is provided to alert licensees to an event involving

a reactor scram at low power following control;rod withdrawal during a turbine

test at the Commonwealth Edison Company's Quad Cities Station.

This event demonstrates the need for careful planning, increased awareness, a

training, proper review and use of procedures, and good communications when

plant is placed in a non-typical mode of operation because of special testing

or other unusual conditions. 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-equirements, therefore, no

specific action or written response is required.

Description of Circumstances

,

On October 27, 1990, Quad Cities, Unit 2, scrammed on a hi-hi intermediate

range scram signal, when the operator withdrew rods to increase reactor

pressure without recognizing the need to follow the normal procedures for re- establishing reactor criticality. The operator focused on controlling

reactor pressure and did not adequately monitor reactivity.

In preparation for performing a turbine torsional test with the reactor at low

power and with the plant not supplying the grid, reactor power and pressure

were reduced to close the turbine bypass valves and thereby allow the electro- hydraulic control (EHC) oil pumps to-be secured and test equipment to be con- nected. The procedure specified that reactor power and pressure be increased

after the temporary alterations were made. However, the licensee provided

no special training for performing the turbine torsional test and the plant

staff was unaware that the plant conditions required by the test were difficult

to maintain. In addition, the licensee's procedures were not sufficiently

comprehensive to ensure stable plant operation during installation or removal

of the test equipment.

91 C

r1i'- /

IN 91-04 January 28, 1991 At The Shift 1 crew inserted control rods to decrease reactor power and

to permit installation of the test equipment. At the end of Shift 1,pressure

reported to the Shift 2 nuclear station operator (NSO) that they had the crew

experienced

high rod notch worth (i.e., large reactivity changes with relatively

small

amounts of rod movement) during these manipulations. However, the information

was not recorded in the Unit 2 log book. During Shift 2, the testing

performed because of problems in controlling the turbine acceleration was not

The information on high rod notch worth that was received by Shift 2 rate.

was not

relayed to Shift 3.

Shortly after the start of Shift 3, the testing was aborted, and the

engineer (SE) told the shift control room engineer (SCRE) to return toshift

operation. The SCRE instructed the Unit 2 NSO to decrease reactor pressurepower

to approximately 800 psig to ensure that the turbine bypass valves would

closed and to permit the securing of the EHC system and the removing be

of the

test equipment. The SCRE then became preoccupied with other activities

as relnerting the drywell and did not supervise the NSO's actions. such

failed to use the procedure for going from power to hot standby. The The NSO

monitored pressure as he inserted rods, but failed to stop when the NSO

power dropped below the point of adding heat and went subcritical. reactor

When all

bypass valves were closed and reactor pressure was approximately 805 decreasing, the NSO attempted to withdraw control rods to stabilize psig and

but was prevented because of a rod block caused by a low count rate pressure, source range monitor (SRM). After clearing the rod block by insertingon the

SRMs and as the NSO began withdrawal of control-rods~theeactor becamethe

supercritical and scrammed on hi-hi intermediate range flux. A complete

discussion of this event may be found in the Public Document Room in

a memo- randum dated December 28, 1990, from Jack E. Rosenthal, Division of Safety

Programs, Office for Analysis and Evaluation of Operational Data, Thomas M. Novak, SUBJECT: HUMAN FACTORS STUDY REPORT - QUAD CITIESto2

(10/27/90).

Discussion:

The safety significance of this event is that the plant was placed

non-typical mode of operation without adequate planning, awareness, in a

training, review and use of procedures, and communications. Factors that contributed

the event included the following: to

1. Lack of awareness by the plant staff that the reactor conditions

for the torsional test were difficult to maintain, required

2. Insufficient comprehension of written procedures regarding reactivity

control,

3. Lack of specific training for the performance of the torsional test

for achieving and maintaining the reactor conditions required, and

4. Failure to communicate valuable information from previous shifts, and

5. Lack of adequate supervision of the nuclear operator.

IN 91-04 January 28, 1991 Page:3 of 3 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 NRR project manager.

Chares.oss, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: E. Trager, AEOD

(301) 492-4496 B. Kaufer, AEOD

(301) 492-4544 Attachment: List of Recently Issued NRC Information Notices

Attchmnt 1 LIST OF RECENTLY ISSUED January 25, 1991 NRCINFORMIATION NOTICES Page I of i

Ietoroation taate oof

_ tte* Ka. Sub3ect Issuence Issued to

---

----

91-03 Management Of Wastes Contaminated 01/07/I1 All medical licensees.

with Radioactive Materials ("Red

sage Waste and Ordinary Trash)

91-02 trachytherapy Source Management 01/07/91 All Nuclear Regulatory

Cormission (NRC) medi- cal licensees author- ized to use byproduct

material for medical

purposes.

91-01 Supplier of Misrepresented 01/04/91 All holders of OLs or

Resistors CPs for nuclear power

reactors.

90-12 Requirements for Use Of 1/31/90 All registered users

Nuclear Regulatory Cor- of NRC-approved

packages.

ission-(NRC-)Approved

Transport Packages for

Shiprent of Type A quanti- ties of Radioactive Materials.

fitness for Duty 12/24/10 All U.S. Nuclear

Regulatory Coulssion

(IIRC) material and

mon-power reactor

licensees.

90-80 Sand Intrusion Resulting 12/21/90 All holders of OLs or

in Two Diesel generators CPs for nuclear power

Becoming Inoperable reactors.

90-79 Failures of Main Stean 12/20/90 All holders of OLsaor

Isolation Check valves CUs for nuclear power

Resulting In Disc Separation reactors.

90-78 Previously Unidentified 12/15/90 All holders of OLs or

Release Path from Boiling Vts for eo111no wat r

Water Reactor Control Rod reactbrs (WRs).

lydraulic Units

90-77 Inadvertent Removal of Fuel 12/12/90 All holders of OLs or

Asseblies from the Reactor CPs for pressurized- Core water reactors (PWRS).

OL

• Operating License

CP a Construction Permit

IN 91-04 January 28, 1991 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 NRR project manager.

Original SIgytI41Y

Chades F R1oW

Charles E. Rossi, Director

D1i1v1on of Operdtional Events Assesswent

Office of Nuclear Reactor Regulation

Technical Contacts: E. Trager, AEOD

(301) 492-4496 B. Kaufer, AEOD

(301) 492-4544 Attachment: List of Recently Issued NRC Information Notices

It ,i .5>t

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SEE PREVIOUS CONCURRENCES. v / i/ 'I l

OFC :OEAB :TechEd :SC:OEAB :C:OEAB :C:OGCB OD: Q );NRR:

NAME :*TGreene

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DATE :01/15/91 :01/15/91 :01/16/91 :01/17,18/91 :01/22/91  : t/of4I //

OFFICIAL RECORD COPY£

Document Name: IN 9J-04

IN 91- rJ

January XW', 1991 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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: E. Trager, AEOD

(301) 492-4496 B. Kaufer, AEOD

(301) 492-4544 Attachment: List of Recently Issued NRC Information Notices

OFC :OEAB :SC:OEAB OCa

CC:OE'. D:DOEA:NRR  :

NAME :TGreene :Tech Ed :HBailey haffee :CBerlinger :CRossi 9e

DATE :01/15/91 :01/15/91 :01/16/91 :01/17/91  :#OI# /  : / /  :

OFFICIAL RECORD COPY

Document Name: INFO/NOTICE/TRAGER

9 IN 91-XX

January XX, 1991 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 NRR project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: E. Trager, AEOD

(301) 492-4496 B. Kaufer, AEOD

(301) 492-4544 Attachment: List of Recently Issued NRC Information Notices

OFC :OEAB  : :SC: :C:OEAB :C:OGCB :D:DOEA:NRR  :

NAME :TGreene :Tech Ed W

5Wi~fee :CBerlinger :CRossi

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DATE ///:*l/Sl : /ji :1'YI

l/15l  : l 9  : / /  : / /  :

OFFICIAL RECORD COPY

Document Name: INFO/NOTICE/TRAGER