Information Notice 1997-41, Revised - Potentially Undersized Emergency Diesel Generator (EDG) Oil Coolers

Revised - Potentially Undersized Emergency Diesel Generator (EDG) Oil Coolers

ML031050489
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:	06/27/1997
From:	Slosson M Office of Nuclear Reactor Regulation
To:
References
IN-97-041, NUDOCS 9706230171
Download: ML031050489 (7)

UNITED STATES "REVISED PAGE"

NLEAR REGULATORY COMMISSION, ADDRESSEE LINE

OFFICE OF NUCLEAR REACTOR REGULATION CHANGED

WASHINGTON, D.C. 20555-0001 June 27, 1997 NRC INFORMATION NOTICE 97-41: POTENTIALLY UNDERSIZED EMERGENCY

DIESEL GENERATOR (EDG) OIL COOLERS

Addresses

All holders of operating licenses or construction permits for nuclear power reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alert

addressees to the discovery of potentially undersized EDG oil coolers at Limerick

Generating Station, Units 1 and 2. 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 are not NRC

requirements; therefore, no specific action or written response is required.

Description of Circumstances

Philadelphia Electric Company (PECO) Nuclear, the licensee for Limerick Generating

Station, Units I and 2, and its consultant Stone and Webster were recently evaluating EDG

heat exchangers in response to NRC Generic Letter (GL) 89-13. In the course of this

evaluation it was determined that the Limerick EDG lubricating oil coolers were undersized

relative to the design conditions reported on the heat exchanger data sheet. The oil coolers

in question are used to cool lubricating oil for the Coltec EDGs and were designed and

manufactured by American Standard in May 1976. The cooling water for heat removal

circulates through the tubes and the lubricating oil circulates on the shell side. Finned

tubes are used to provide additional heat transfer surface. In the process of verifying the

design adequacy of the heat exchanger, the licensee utilized the widely used computer

modeling program ST-5, Mod 0.5-1.3, developed by Heat Transfer Research Inc. (HTRI).

HTRI is the leading association for the heat-exchanger industry; its membership includes all

major heat exchanger manufacturers and designers. The licensee used data obtained from

the design data sheet of the heat exchanger. This data included the design geometry and

design conditions, as well as the tube-side fouling factor of 0.002 and the oil-side heat

transfer rate of 83.2 BTUI(hr ft2 'F) for SAE 30 oil. The calculation indicated that the heat

exchanger was 22.8 percent undersized. The licensee informed Coltec about this

discrepancy and requested further evaluation.

Discussion

An evaluation performed by Coltec and its consultants indicates that all design calculations

performed by American Standard in 1976 for this heat exchanger were complete and

correct, TR Is NOrICEt 9 7C7061

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IN 97-41 June 27 1997 including the proper application of the finned tubing surface area ratio to the specified tube- side fouling factor. PECO Nuclear and its consultant originally suspected that the 0.002 fouling factor was erroneously applied unmodified to the outside surface in the original design

of the heat exchanger, resulting in an undersized heat transfer surface. The evaluation

demonstrated that this was not the case. Heat transfer calculations supported by HTRI at the

time of design were considered "state of the art" and the heat exchanger design was based

on the methodology that was current at that time.

The discrepancy between the newly calculated and original design heat transfer surfaces, according to Coltec and is consultants, was caused by a revision in the calculational

methodology for designing heat exchangers implemented in 1985. Calculations based on the

revised method invariably lead to a lower heat transfer surface in comparison with the

previously used calculation procedure. Thus heat exchangers designed before 1985, if

evaluated in accordance with the revised design methods, would be considered undersized.

In 1985, after extensively testing industrial-sized heat exchangers, HTRI modified its

calculation method for cooling viscous shell side fluids. The new calculation method is

considered to be more precise in predicting actual heat transfer and pressure drop

performance. In general, the calculated shell-side heat transfer coefficients obtained with this

revised method are lower than those obtained with the former method. In some cases, the

coefficient can be appreciably lower, depending on fluid viscosity, operating temperatures, flow velocity, and fin geometry.

It therefore appears that heat exchangers designed before 1985 are smaller in size for the

same performance requirements than those designed after 1985. This does not necessarily

mean that they are now considered inadequate for meeting the design requirements. It, however, does mean that they have a lower fouling margin, possibly requiring more frequent

cleaning and testing of the heat exchangers in order to maintain operability. PECO Nuclear

has determined that for the Limerick design, sufficient margin is available given the calculated

temperatures of the emergency service water (ESW) system to handle the post-accident

loading (which is below the continuous rating). PECO Nuclear's analysis takes into

consideration the seasonal variation of ambient temperatures and the results indicate that by

scheduling of the heat exchanger cleaning precisely, Limerick will be able to maintain EDG

operability. Evaluation of similar heat exchangers of the same vintage may yield similar

results.

IN 97-41 June 27, 1997 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.

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Jai Rajan, NRR

301415-2788 E-mail: jrr@nrc.gov

John R. Tappert, NRR

301415-1167 E-mail: jrt@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

A[, '-5cAtr

Attachment

IN 97-41 June 27, 1997 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

97-40 Potential Nitrogen 06/26/97 All holders of OLs or CPs

Accumulation Resulting for pressurized-water

from Bakickakage from reactors

Safety Injection Tanks

97-39 Inadequate 10 CFR 72.48 06/26/97 All holders of OLs or CPs

Safety Evaluations of for nuclear power reactors.

Independent Spent Fuel All holders of licenses for

Storage Installations independent spent fuel

storage installations

97-38 Level-Sensing System 06/24/97 All holders of OLs or CPs

Initiates Common-Mode for nuclear power reactors

Failure of High-Pressure- Injection Pumps

96-53, Retrofit to Amersham 660 06/23/97 All industrial radiography

Supp. 1 Posilock Radiography licensees

Camera to Correct Incon- sistency in 10 CFR Part 34 Compatibility

97-37 Main Transformer Fault 06/20/97 All holders of OLs or CPs

with Ensuing Oil Spill for nuclear power reactors

into Turbine Building

97-36 Unplanned Intakes by 06/20/97 All holders of OLs and CPs

Worker of Transuranic permits. All licensees of

Airborne Radioactive of nuclear power reactors

Materials and External in the decommissioning

Exposure Due to Inadequate stage and fuel cycle

Control of Work

OL = Operating License

CP = Construction Permit

IN 97-41 June 27, 1997 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.

original signed by S.H. Weiss for

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Jai Rajan, NRR

301-415-2788 E-mail: jrr@nrc.gov

John R. Tappert, NRR

301-415-1167 E-mail: jrt2nrc.gov

Attachment: List of Recently Issued NRC Information Notices

Tech Editor has reviewed and concurred on 5121/97 DOCUMENT NAME: 97-41.IN *SEE PREVIOUS CONCURRENCES

To receive a copy of this document Indicate In the box c=Copy w/o attachmentlendosure E=Copy with attadhmentlendosure N = No copy

OFFICE Tech EMEB* C:PECB* D:DRPM

Contacts*

NAME JRajan DWessman AChaffee MSlosso

_ __ _ _ _ _ JTa ppe rt_ _ _ _ _ _ _ _ _ _ _

DATE 6/09197 6/09/97 6/16/97 6Z297 /

6/12/97 OFFICIAL RECORD COPY

• . ^ *

IN 97-XX

June x, 1997 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.

Marylee M. Slosson, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Jai Rajan, NRR

301-415-2788 E-mail: jrr@nrc.gov

John R. Tappert, NRR

301-415-1167 E-mail: jrt@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME:G:\RAJAN\EDGCOO.LER *SEE PREVIOUS CONCURRENCES

To receive a copy of this document Indicate in the box C=Copy wlo zmnramPnT1PrvInoiirA E=Copy with attachmentlendosure N = No copy

OFFICE Tech EMEB* C:PECB* D:DRPM

l__Conta_ ct s*ctl

NAME JRajan DWessman AChaffee MSlosson

JTappert

DATE 6/09/97 6/09/97 6/16/97 6/ /97

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IN 97-XX

June xx, 1997 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.

Thomas T. Martin, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Jai Rajan, NRR

301-415-2788 E-mail: jrr@nrc.gov

John R. Tappert

301-415-1.167 E-mail: jrt@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME:G:ARAJAN\EDGCOO.LER

To receive a copy of this document, indicate in the box C=Copy wlo attachment/enclosure E=Copy with attachmentlenclosure N - No copy

• Cogv'AA Huff -e

OFFICE Tech EMEB CI:PECB D:DRPM

Contacts Adf rf f

NAME JRajan IA DWessman AChaffee MSlosson

JTappert M71 I I :1 DATE _6/97 6/7 /97 OFFICIAL

.1 6/ /97 OFFICIAL RECORD COPY