Information Notice 1995-54, Decay Heat Management Practices During Refueling Outages

Decay Heat Management Practices During Refueling Outages

ML031060243
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:	12/01/1995
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:
References
IN-95-054, NUDOCS 9511290233
Download: ML031060243 (11)

.. I

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 December 1, 1995 NRC INFORMATION NOTICE 95-54: DECAY HEAT MANAGEMENT PRACTICES DURING

REFUELING OUTAGES

Addressees

permits for nuclear power

All holders of operating licenses or construction

reactors.

Purgose

is issuing this information

The U.S. Nuclear Regulatory CommissionNRC(NRC) of licensee control of

notice to alert addressees to recent for assessments decay heat produced from the

refueling operations and the methods fuel removing

pool. It is expected that recipients

irradiated fuel stored in the spent to their facilities and consider

will review the information for applicability problems. However, suggestions

actions, as appropriate, to avoid similar

contained in this information notice is are not NRC requirements; therefore, no

specific action or written response required.

Background

and associated procedural controls

The staff recently reviewed a design change systems at Millstone Nuclear

regarding spent fuel pool decay heat removal controls at Cooper Nuclear

Power Station, Unit 1, and full-core offloading

controls on irradiated fuel movement and

Station. The staff evaluated overall heat removal during refueling operations, the control of irradiated fuel decay safety analysis report commitments, including adequate adherence to final and effectiveness of

implementation of procedures, procedural adequacy, training.

Description of Circumstances

Millstone Unit 1

On October 18, 1993, the licensee for Millstone Unit 1 submitted Licensee

Event Report (LER) 93-11, in which itmay reported that it had determined through

engineering analysis that conditions have existed during which the spent

incapable of maintaining spent fuel

fuel pool cooling system may have been criteria of 66;C [150'F] design limit

pool temperature below the licensee's LER stated that (1)the licensee

for continued operation. Specifically,thetheanalysis performed in support of a

had made inappropriate assumptions in (2)the "normal" refueling sequence

1988 spent fuel pool re-rack project, Final Safety Analysis Report assumed

described in the Millstone Unit 1 Updated a full-core offload considered in the

offload of only one third of a core, (3) (or abnormal discharge) offload was

safety analysis report as an "emergency" (4)under certain circumstances

normally performed at Millstone Unit 1, and

9511290233 PP Xi- IOtl'C. ASHORE L4

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pus < IN 95-54 December 1, 1995 Millstone Unit 1 may have operated outside its design basis for the spent fuel

pool.

The licensee recently implemented a modification to the shutdown cooling

system to provide additional spent fuel pool decay heat removal capability.

In a July 28, 1995 submittal, the licensee stated that the modification would

enable Millstone Unit 1 to perform a full core discharge as a normal offload

practice. Coincident with the development of the modification, the licensee

proposed a license amendment to impose technical specification controls on

shutdown cooling system operability, spent fuel pool temperature and decay

time prior to beginning offload activities. In response to staff questions, the licensee stated it had concluded during a review pursuant to 10 CFR 50.59, that the proposed modification did not represent an unreviewed safety question

and as such did not require prior NRC approval, and that the license amendment

was not required but was being submitted to remove ambiguity regarding the

full core offload refueling practice.

During its review of the procedural controls for the shutdown cooling-spent

fuel pool cooling cross-connect, the staff found that the administrative

procedures for the cross-connect, including controls for the cross-connect

valves and the spent fuel pool-reactor vessel weir gate were not sufficiently

explicit. The licensee addressed these concerns. Because the requested

specifications did not meet the criteria of 10 CFR 50.36 for inclusion as

limiting conditions of operation in the technical specifications, the staff

issued a license condition. The license condition specifies that refueling

operations that include full core offload be conducted in accordance with the

revised controls proposed by the licensee.

Cooper Nuclear Station

On October 20, 1995, the operators of the Cooper nuclear station halted

movement of fuel from the reactor vessel to the spent fuel pool to perform a

review of the design and licensing basis and administrative controls

associated with the removal of decay heat from the spent fuel pool. The

licensee concluded that no licensing restrictions regarding the practice of

conducting a full-core offload existed with regard to decay heat removal. The

licensee further concluded that the installed spent fuel pool cooling system

and backup fuel pool cooling inter-tie from the residual heat removal system

had sufficient capacity to remove the decay heat from the irradiated spent

fuel and reactor cavity for postulated heat loads up to and including those

associated with a full-core offload.

However, the licensee acknowledged that the description of the spent fuel pool

cooling system in the Cooper Updated Safety Analysis Report was confusing and

ambiguous. Consequently, the licensee proposed revisions to that document to

clarify ambiguous language and performed a 10 CFR 50.59 analysis, which

documented the evaluation of the plant's licensing basis for the design and

operation of the spent fuel pool cooling system. Upon approval of the changes

by the Station Operations Review Committee, the licensee updated its refueling

procedures to be consistent with the revised safety analysis report, and

proceeded with the full-core offload.

V

\<J IN 95-54 December 1, 1995 Discussion

The functional capability to protect irradiated fuel from damage due to

inadequate decay heat removal is an important safety attribute. Maintaining

spent fuel pool water temperature below boiling temperature provides adequate

cooling for stored irradiated fuel. However, prolonged operation at elevated

spent fuel pool temperatures may impair the capability of the purification

system to remove contaminants from the spent fuel pool coolant and increase

the rate of heat addition to the fuel storage area atmosphere to a value above

that assumed in the ventilation system design. In addition, high spent fuel

pool temperatures may exceed the temperature used for thermal stress

computation in the structural analysis of the spent fuel pool liner and the

spent fuel pool structure itself.

Shutdown cooling systems, which are aligned to directly cool the reactor

vessel or reactor coolant system, are designed to remove the residual and

decay heat associated with the irradiated fuel in the reactor vessel in order

to bring the reactor coolant system to the cold shutdown condition. Licensees

typically have procedures to maintain the removal of decay heat from the

vessel at all times while irradiated fuel is in the reactor vessel.

Similarly, systems are also installed in nuclear power plants to remove from

the spent fuel pool, decay heat generated by the stored irradiated fuel.

However, these spent fuel pool cooling systems are designed with a lower heat

removal capacity relative to the shutdown cooling system based on the decrease

in decay heat generation within the irradiated fuel as the time after reactor

shutdown increases. At some facilities, including most boiling water reactors

and some pressurized water reactors, the spent fuel pool cooling system is not

designed to remove the decay heat associated with a full core immediately

after shutdown and still maintain a bulk spent fuel pool temperature below

design-basis limits. However, these facilities are designed with backup spent

fuel pool cooling systems, which are generally alternative operating modes of

the residual heat removal or shutdown cooling systems, that supplement the

spent fuel pool cooling system during periods shortly after reactor shutdown

when the decay heat load of a full core may exceed the heat removal capacity

of the normal spent fuel pool cooling system.

The capability of spent fuel pool cooling systems and backup spent fuel decay

heat removal systems is described in the Final Safety Analysis Report, as

updated for nuclear power plants. The decay heat load scenarios used to

evaluate the adequacy of system heat rejection capability may be based on a

series of core offloads and an associated decay time. These scenarios may be

described as "normal" or "abnormal" maximum heat loads for this purpose, which

is consistent with the NRC staff guidance for the review of spent fuel pool

cooling system design contained in Section 9.1.3 of the Standard Review Plan

(NUREG-0800).

Recent licensee reviews of refueling outage practices at Millstone Unit 1 and

Cooper found that the system design bases specified in Final Safety Analysis

Reports, as related to core offload practices, were ambiguous. Administrative

controls on refueling outage plans and practices were inconsistent in regard

s<-a IN 95-54 December 1, 1995 fuel pool were

to ensuring that temperature commitments for the spent Both licensees, after

maintained through all phases of refueling operation. controls related

clarifying and improving the design bases and administrative of performing full

to refueling outages, determined that a routine practice

core offloads was acceptable.

to potential

The NRC has issued two information notices to alert licensees NRC Information

risks associated with a loss of spent fuel pool cooling. After a Loss-of- Notice 93-83, "Potential Loss of Spent Fuel Pool Cooling concerns found at

Coolant Accident," was issued October 7, 1993, and described

Notice 93-83, Susquehanna Steam Electric Station. NRC Informationlicensees of the results of

Supplement 1, was issued August 8, 1995, to inform

the NRC review of the concerns at Susquehanna.

notices, and the plant

The events described in this and previous information of:

reviews discussed above, illustrate the importance

refueling

• assuring that planned core offload evolutions, including with the

practices and irradiated decay heat removal, are consistent

Safety Analysis Report, technical

licensing basis, including the Final

specifications, and license conditions;

of the

• assuring that changes are evaluated through the application

provisions of 10 CFR Part 50.59, as appropriate; and

core offloads have

• assuring that all relevant procedures associated with

been appropriately reviewed.

to the need to

The staff is continuing to review this matter with respect

issue additional generic communications.

written response. If

This information notice requires no specific action or

notice, please contact

you have any questions about the information in this Office of

one of the technical contacts listed below or the appropriate

Nuclear Reactor Regulation (NRR) project manager.

ennis M. Crutch ld Director

Division of Reactor PrormMnget

Office of Nuclear Reactor Regulation

Technical contacts: Joseph W. Shea, NRR Steven R. Jones, NRR

(301) 415-1428 (301) 415-2833 David L. Skeen, NRR

(301) 415-1174 Attachment: List of Recently Issued NRC Information Notices

&( ork

"-Ketachment

IN 95-54 December 1, 1995 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Subject Issuance Issued to

Notice No.

12/01/95 All holders of OLs or CPs

95-53 Failures of Main Steam for nuclear power reactors.

Isolation Valves as a

Result of Sticking

Solenoid Pilot Valves

Unexpected Opening of a 11/30/95 All holders of OLs or CPs

95-47, for nuclear power reactors.

Rev. 1 Safety/Relief Valve and

Complications Involving

Suppression Pool Cooling

Strainer Blockage

Control and Oversight of 11/28/95 All holders of OLs or CPs

94-13, for nuclear power reactors.

Supp. 2 Contractors during Re- fueling Activities and

Clarificaiton of Applica- bility of Section 50.120 of

Title 10 of The Code of

Federal Regulations to

Contractor Personnel

Potential for Data 11/22/95 All holders of OLs or CPs

95-13, for nuclear power reactors.

Supp. 1 Collection Equipment to

Affect Protection System

Performance

11/22/95 All holders of OLs or CPs

91-29, Deficiencies Identified for nuclear power reactors.

Supp. 3 during Electrical

Distribution System

Functional Inspections

Legal Actions Against 11/15/95 All holders of OLs or CPs

94-86, for nuclear power reactors.

Supp. 1 Thermal Science, Inc.,

Manufacturer of Thermo-Lag

Fire Endurance Test Results 11/14/95 All holders of OLs or CPs

95-52 for nuclear power reactors.

for Electrical Raceway Fire

Barrier Systems Constructed

from 3M Company Interam Fire

Barrier Materials

OL = Operating License

CP = Construction Permit

IN 95-54 December 1, 1995 to ensuring that temperature commitments for the spent fuel pool were

maintained through all phases of refueling operation. Both licensees, after

clarifying and improving the design bases and administrative controls related

to refueling outages, determined that a routine practice of performing full

core offloads was acceptable.

The NRC has issued two Information notices to alert licensees to potential

risks associated with a loss of spent fuel pool cooling. NRC Information

Notice 93-83, "Potential Loss of Spent Fuel Pool Cooling After a Loss-of- Coolant Accident," was issued October 7, 1993, and described concerns found at

Susquehanna Steam Electric Station. NRC Information Notice 93-83, Supplement 1, was issued August 8, 1995, to inform licensees of the results of

the NRC review of the concerns at Susquehanna.

The events described in this and previous information notices, and the plant

reviews discussed above, illustrate the importance of:

• assuring that planned core offload evolutions, including refueling

practices and irradiated decay heat removal, are consistent with the

licensing basis, including the Final Safety Analysis Report, technical

specifications, and license conditions;

• assuring that changes are evaluated through the application of the

provisions of 10 CFR Part 50.59, as appropriate; and

• assuring that all relevant procedures associated with core offloads

have been appropriately reviewed.

The staff is continuing to review this matter with respect to the need to

issue additional generic communications.

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 Office of

Nuclear Reactor Regulation (NRR) project manager.

Dennis M. Crutchfield, Director orig /s/'d by DMC

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Joseph W. Shea, NRR Steven R. Jones, NRR

(301) 415-1428 (301) 415-2833 David L. Skeen, NRR

(301) 415-1174 Attachment: List of Recently Issued NRC Information Notices

TechEd reviewed this document 11/22/95.

DOCUMENT NAME: 95-54.IN

• - See previous concurrence /

To receive a copy of this document, indicate in the box CxCopy w/o attachmentlenclosure E-Copy with * t/nclosure N

• No copy

OFFICE NRR I C/PECB:DRPM I D/DSSA I DXIM

NAME Tech Contacts* AChaffee* GHolahan* &'fi eld l

DATE 11/21/95 11/29/95 111/29/95 7 0t(i/95I

OFFICIAL RECORD COPY

IN 95-54 November 30, 1995 Susquehanna Steam Electric Station. NRC Information Notice 93-83, Supplement 1, was issued August 8, 1995, to inform licensees of the results of

the NRC review of the concerns at Susquehanna.

The events described in this and previous information notices, and the plant

reviews discussed above, illustrate the importance of:

• assuring that planned core offload evolutions, including refueling

practices and irradiated decay heat removal, are consistent with the

licensing basis, including the Final Safety Analysis Report, technical

specifications, and license conditions.

• assuring that changes are evaluated through the application of the

provisions of 10 CFR Part 50.59, as appropriate.

• assuring that all relevant procedures associated with core offloads have

been appropriately reviewed.

The staff is continuing to review this matter with respect to the need to

issue additional generic communications.

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 Office of

Nuclear Reactor Regulation (NRR) project manager.

Dennis M. Crutchfield, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Joseph W. Shea, NRR Steven R. Jones, NRR

(301) 415-1428 (301) 415-2833 David L. Skeen, NRR

(301) 415-1174 Attachment: List of Recently Issued NRC Information Notices

• - See Drevious concurrence

OFC PECB:DRPM jSPLB:DSSA PD I-2:DRPE D/DSSA

NAME DSkeen* SJones* JShea* GHolahan*

DATE 111/21/95 111/21/95 11/22/95 11/29/95 OFC D/DRPE C/PECO:DRPM D/DRPM

NAME SVarga* A ffee DCrutchfield

DATE 11/27/95 l11/29/95 11/ /95

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[OFFICIAL RECORD COPY] DOCUMENT NAME: G:\UL5\1N95-XX.5ff

IN 95-XX

November XX, 1995 review of the concerns at Susquehanna.

The events described in this and previous information notices, and the plant

reviews discussed above, illustrate the importance of:

• assuring that planned core offload evolutions, including refueling

practices and irradiated decay heat removal, are consistent with the

licensing basis, including the Final Safety Analysis Report, technical

specifications, and license conditions.

• assuring that changes are evaluated through the application of the

provisions of 10 CFR Part 50.59, as appropriate.

• assuring that all relevant procedures associated with core offloads have

been appropriately reviewed.

The staff is continuing to review this matter with respect to the need to

issue additional generic communications.

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 Office of

Nuclear Reactor Regulation (NRR) project manager.

Dennis M. Crutchfield, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Joseph W. Shea, NRR Steven R. Jones, NRR

(301) 415-1428 (301) 415-2833 David L. Skeen, NRR

(301) 415-1174 Attachment: List of Recently Issued NRC Information Notices

• - See previous concurrence

OFC PECB:DRPM SPLB:DSSA PD I-2:DRPE D/DSSA

NAME DSkeen* SJones* JShea* GHolahan*

DATE 11/21/95 111/21/95 11/22/95 111/29/95 OFC ID/DRPE IC/PJM:DRPM ID/DRPM

NAME SVarga* _ _ __eeDCrutchfield

_AC_

DATE 11/27/95 11/29/95 11/ /95

[OFFICIAL RECORD COPY] DOCUMENT NAME: G:\DLS\IN95-XX.SFP

IN 95-XX

November XX, 1995 review of the concerns at Susquehanna.

The events described in this and previous information notices, and the plant

reviews discussed above, illustrate the importance of:

• assuring that planned core offload evolutions, including refueling

practices and irradiated decay heat removal, are consistent with the

licensing basis, including the Final Safety Analysis Report, technical

specifications, and license conditions.

• assuring that changes are evaluated through the application of the

provisions of 10 CFR Part 50.59, as appropriate.

• ensuring that all relevant procedures associated with core offloads have

been appropriately reviewed.

The staff is continuing to review this matter with respect to the need to

issue additional generic communications.

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 Office of

Nuclear Reactor Regulation (NRR) project manager.

Dennis M. Crutchfield, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Joseph W. Shea, NRR Steven R. Jones, NRR

(301) 415-1428 (301) 415-2833 David L. Skeen, NRR

(301) 415-1174 Attachment: List of Recently Issued NRC Informaticin Notices

• - See Drevious concurrence

OFC PECB:DRPM SPLB:DSSA PD I-2:DRPE 1 NAME DSkeen* SJones* JShea* I ol ahan

DATE 11/21/95 11/21/95 11/22/95 I / 95

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DATE 11/27/95 / /95 I/ /95 FiCAL CY-U-AM

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[OFFICIAL RECORD COPY]

IN 95-XX

November XX, 1995 Notice 93-83, "Potential Loss of Spent Fuel Pool Cooling After a Loss-of- Coolant Accident," was issued October 7, 1993, and described concerns found at

Susquehanna Steam Electric Station. NRC Information Notice 93-83, Supplement

1, was issued August 8, 1995, to inform licensees of the results of the NRC

review of the concerns at Susquehanna.

The events described in this and previous information notices, and the plant

reviews discussed above, illustrate the importance of performing the following

actions in a timely manner:

• evaluating the licensing basis, including the Final Safety Analysis

Report, technical specifications, and license conditions, as it pertains

to refueling practices and irradiated fuel decay heat removal.

• ensuring that all relevant procedures associated with core offloads have

been thoroughly reviewed and analyzed by the appropriate onsite review

committee, per 10CFR, Part 50, Appendix B.

• effectively implementing the necessary training to ensure the above

requirements are met.

The staff is continuing to review this matter with respect to the need to

issue additional generic communications.

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 Office of

Nuclear Reactor Regulation (NRR) project manager.

Dennis M. Crutchfield, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Joseph W. Shea, NRR Steven R. Jones, NRR

(301) 415-1428 (301) 415-2833 David L. Skeen, NRR

(301) 415-1174 Attachment: List of Recently Issued NRC Information Notices

• - See previous concurrence

OFC PECB:DRPM SPLB:DSSA PD I-2:DRPE D/DSSA

NAME DSkeen* SJones* JShea* GHolahan

DATE 111/21/95

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IN 95-XX

November XX, 1995 * Licensees are expected to ensure that all relevant procedures associated

with a full-core offload have been thoroughly reviewed and analyzed by

the appropriate onsite review committee.

• Licensees are expected to effectively implement the necessary training

to ensure the above requirements are met.

Related Generic Communications

The NRC has issued two information notices to alert licensees to potential

risks associated with a loss of spent fuel pool cooling. NRC Information

Notice 93-83, "Potential Loss of Spent Fuel Pool Cooling After a Loss-of- Coolant Accident," was issued on October 7, 1993, and described concerns found

at Susquehanna Steam Electric Station (Susquehanna). NRC Information Notice 93-83, Supplement 1, was issued on August 8, 1995, to inform licensees of the

results of the NRC review of the concerns at Susquehanna.

Since October 1994, the staff has been implementing a generic action plan to

review concerns related to SFPs. Additional generic communications may be

issued at the completion of the staff's generic review.

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 Office of

Nuclear Reactor Regulation (NRR) project manager.

Dennis M. Crutchfield, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Joseph W. Shea, NRR Steven R. Jones, NRR

(301) 415-1428 (301) 415-2833 David L. Skeen, NRR

(301) 415-1174 Attachment: List of Recently Issued NRC Information Notices

OFC PECB:DRPM SPLB:DSS X PD I-2:DRPE D/DSSA

NAME DSkee SJones X :hea

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DATE ZI/95 ,It /,X295 1 /Z2/95 / /95 OFC I D/DRPE I C/PECB:DRPM I D/DRPM

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