Information Notice 1996-39, Estimates of Decay Heat Using ANS 5.1 Decay Heat Standard May Vary Significantly

Estimates of Decay Heat Using ANS 5.1 Decay Heat Standard May Vary Significantly

ML031060021
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Issue date:	07/05/1996
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-96-039, NUDOCS 9606250199
Download: ML031060021 (15)

KY/UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 July 5, 1996 NRC INFORMATION

NOTICE 96-39: ESTIMATES

OF DECAY HEAT USING ANS 5.1 DECAY HEAT STANDARD MAY VARY SIGNIFICANTLY

Addressees

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 sensitivity

of analytical

results to input parameters

used with American Nuclear Society standard 5.1 on decay heat (Reference).

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.Background

American Nuclear Society standard 5.1 (ANS 5.1 standard)

for decay heat generation

in nuclear power plants provides a simplified

means of estimating

nuclear fuel cooling requirements

that can be readily programmed

into computer codes used to predict plant performance.

The ANS 5.1 standard models the energy release from the fission products of U-235, U-238, and Pu-239 using a summation

of exponential

terms with empirical

constants.

Corrections

are provided to account for energy release from the decay of U-239 and Np-239, and for the neutron activation

of stable fission products.

Although the empirical constants

are built into the standard, certain data inputs are left to the discretion

of the user. These options permit accounting

for differences

in power history, initial fuel enrichment, and neutron flux level.Description

of Circumstances

During a review of decay heat estimates

calculated

using various codes for the same plant, the staff found that the predicted

decay heat varied considerably.

This was unexpected

because the analyses were made using the 1979 ANS 5.1 standard and were to be used in best-estimate" thermal-hydraulic

analyses.The staff compared calculations

of decay heat using MELCOR, TRAC, RELAP, and a vendor code for a pressurized

water reactor operating

at 1933 megawatts thermal (MWT). The staff made 3 calculations

using RELAP but varied certain inputs. These calculations

appear as RELAP,, RELAP 2 , and RELAP in the following

tables. The decay heat estimates

in MWT calculated

?or 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> PD& IC ';cs 95-o3q 9(.oqoS 9606250199

1 O A 0o 161b ussOAf '~'k

IN 96-39 July 5, 1996 after shutdown of the reactor using the various codes and allowable

inputs were as follows: MELCOR -20.70 MWT Vendor code -22.15 MWT RELAP 1 -22.02 MWT RELAP 2 -26.13 MWT RELAP 3 -20.82 MWT TRAC -22.02 MWT ORIGEN -20.90 MWT It should be noted that the differences

in predicted

decay heat resulted from the parameters

selected for input and not from the codes themselves.

The last entry in the table was not calculated

by the ANS 5.1 standard but was calculated

by the ORIGEN computer code. ORIGEN does not use empirical

methods to calculate

decay heat but tracks the buildup and decay of the individual

fission products within the reactor core during operation

and shutdown.ORIGEN also includes the effect of element transmutation

from neutron capture, both in fissile isotopes and fission products.

Because ORIGEN is a rigorous calculation

of all decay heat inputs, it was used in the calculations

for decay heat in attached Figure 1 and is contrasted

with attached Figure 2 using decay heat internally

calculated

by RELAP to the ANS 5.1 standard.Discussion

The staff found that the different

decay heat estimates

occurred because the ANS 5.1 standard was not fully utilized in the selection

of inputs. Attached Table 1 shows the various inputs to the codes to estimate decay heat.Attached Table 2 shows the effect of different

assumptions

on best estimate calculations

of decay heat 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after shutdown of the reactor.The variation

in peak cladding temperatures

with various predictions

of decay heat may be seen by comparing

the attached Figures 1 and 2. These figures are plots of the peak cladding temperatures

for a hypothetical

beyond-design-basis

loss-of-feedwater

event. For Figure 1, values of decay heat predicted

by the ORIGEN code were input directly into RELAP. Figure 2 is the same event with the decay heat internally

calculated

by RELAP using the ANS 5.1 standard.Input assumptions

to the standard were those that produced the highest values of decay heat denoted in Table 1 as RELAP 2.The difference

in predicted

peak core cladding temperatures (approximately

250° K [6300 F]) demonstrates

the importance

of carefully

selecting

required input parameters

when using ANS 5.1 because analytical

results may be significantly

affected.

Depending

on the input parameters

selected the results may be conservative

or nonconservative.

IN 96-39 July 5, 1996 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.Brian K. Grimes, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: W. L. Jensen, NRR (301) 415-2856 Internet:wljenrc.gov

J. L. Birmingham, NRR (301) 415-2829 Internet:jlb4@nrc.gov

Attachments:

1. Table 1, 'Decay Heat Options Using ANS 5.1, 1979" 2. Table 2, "Relative

Importance

of Options 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) After Reactor Shutdown" 3. Figure 1, "Peak Core' Cladding Temperature

Calculated

by ORIGEN" and Figure 2, "Peak Core Cladding Temperature

Calculated

by ANS 5.1" 4. List of Recently Issued NRC Information

Notices Reference: "American

National Standard for Decay Heat Power in Light Water American Nuclear Society Standards

Committee

Working Group, ANS August 29, 1979.Reactors," 5.1, Approved 44A0eiIII

Attachment

1 IN 96-39 July 5, 1996 Table 1. Decay Heat Options Using ANS 5.1, 1979 l I l l Power l Fissile Codes Actinides

R-Factor G-Factor Si History Elements Vendor Yes 0.6 Not ANS 1.347 3 Yrs. 3 RELAP 1 No NA MAX NA Infinite All_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _U 2 3 5 RELAP 2 Yes 1.0 MAX NA Infinite All_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___ ___U 2 3 5 RELAP 3 No NA No NA Infinite All_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _U 2 3 5 MELCOR Yes 0.526 Yes 0.713 1.6 Yrs. 3 TRAC No NA Yes 1.0 Infinite All_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __I_ U 2 3 5 Notes: Actinides:

Neutron adding to the total capture by U238 produces U239 which decays into Np239 which also decays, decay heat. Not all the above code inputs included actinide decay.R-factor:

The actinide production

multiplier.

The standard states that the value of R shall be supplied and justified

by the user.G-factor:

A decay heat multiplier

to account for the effect of neutron capture in fission products.

The standard provides the option of using a maximum value table for the G-factor or a best estimate equation for the first 10,000 seconds.Si: Fissions per initial fissile atom. Si is a multiplier

applied to the G-factor equation.Power History: Length of full-power

operation

before shutdown.Fissile Elements:

The standard permits decay power to be fractionally

attributed

to the fission products of 3 fissile isotopes U235, U238, and Pu239. The vendor input attributed

the fractional

fission product power as 0.487 from U235, 0.069 from U238, and 0.443 from U239. The fractional

fission product power input to MELCOR was 0.647 from U235, 0.0425 from U238, and 0.31 from Pu239. The other code inputs assumed all fission product power came from U235.

Attachment

2* IN 96-39 July 5, 1996 Table 2. Relative Importance

of Options 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) After Reactor Shutdown Complete Set For: Options as InDut and Varied Decay Heat in MWT MELCOR MELCOR assumptions (see Table 1) 20.70______________________________________________________________________________

Increase R from .526 to .6 21.03 Increase Si from .713 to 1.347 21.13 Operation

time from 1.6 years to 3 years 21.40 Vendor fissile isotopes 21.12 Vendor heavy element equation 21.86 Vendor code Vendor G-factor equation 22.15-__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -_ _ _ _ _ _ _ _ _ _ _ _ANS 5.1 G-factor and heavy element eqs. 21.12 No actinides

18.65 Gmax rather than equation 19.44 Infinite operation

20.53 RELAP 1 All fission from U235 22.02 ----------------

RELAP 2 Add actinides

with R=1 26.13 RELAP 3 Remove actinides

and G-factor 20.82 TRAC Include G-factor equation with Si-i 22.02 Note: This table illustrates

the relative importance

of the various options contained

in the 1979 ANS 5.1 standard.

Starting with the decay heat rate calculated

by MELCOR using the inputs listed in Table 1, the options were changed in sequence to those used in the vendor computer code. The options were then changed to those used in the RELAP 1 analyses, the RELAP 2 analyses, the RELAP 3 analyses, and the TRAC analyses.

.i Figure 1 Peak Core Cladding Temperature

1400.0 1200.0 2'CD E 0 1000.0 800.0 Attachment

3 IN 96-39 July 5, 1996- 12000.0 600.0 L 400.0 -0.0 4000.0 8000.0 Time (s)1400.0 Figure 2 Peak Core Cladding Temperature

Ug 1L&... A& IC C 4 var.qy ntIvat 04 1200.0 1-Infinite Operati All U235 Fissic G=Gmax Actinides

with I£'0 a E 02 1000.0 800.0 ,n..ulLwu

U)Y MIND ;.. I on in 1 R=1/600.0 400.0 L 0.C.........I D 4000.0 8000.0 12000.0 Time (s)

Attachment

4 IN 96-39 July 5, 1996 LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Information

Date of Notice No. Subject Issuance Issued to 96-38 96-37 96-36 96-35 96-34 Results of Steam Generator Tube Examinations

Inaccurate

Reactor Water Level Indication

and Inad-vertent Draindown

During Shutdown Degradation

of Cooling Water Systems Due to Icing Failure of Safety Systems on Self-Shielded

Irradia-tors Because of Inadequate

Maintenance

and Training Hydrogen Gas Ignition during Closure Welding of a VSC-24 Multi-Assembly

Sealed Basket Erroneous

Data From Defective

Thermocouple

Results in a Fire Implementation

of 10 CFR 50.55a(g)

(6) (ii)(A),"Augmented

Examination

of Reactor Vessel" Cross-Tied

Safety Injec-tion Accumulators

Inaccuracy

of Diagnostic

Equipment

for Motor-Operated Butterfly

Valves Requirements

in 10 CFR Part 21 for Reporting

and Evaluating

Software Errors 06/21/96 06/18/96 06/12/96 06/11/96 05/31/96 05/24/96 06/05/96 05/22/96 05/21/96 05/20/96 All holders of OLs or CPs for pressurized

water reactors All pressurized

water reactor facilities

holding an operating

license or a construction

permit All holders of OLs or CPs for nuclear power reactors All U.S. Nuclear Regulatory

Commission

irradiator

licensees

and vendors All holders of OLs or CPs for nuclear power reactors All material and fuel cycle licensees

that monitor tem-perature with thermocouples

All holders of OLs or CPs for nuclear power reactors All holders of OLs or CPs for pressurized

water reactors All holders of OLs or CPs for nuclear power reactors All holders of OLs or CPs for nuclear power reactors 96-33 96-32 96-31 96-30 96-29 OL = Operating

License CP -Construction

Permit

IN 96-39 July 5, 1996 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.OrfIoaw Stgned by Brin K. Grimes Brian K. Grimes, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: W. L. Jensen, NRR (301) 415-2856 Internet:wl

jnrc.gov J. L. Birmingham, NRR (301) 415-2829 Internet:jlb4@nrc.gov

Attachments:

1. Table 1, 'Decay Heat Options Using ANS 5.1, 1979" 2. Table 2, 'Relative

Importance

of Options 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) After Reactor Shutdown" 3. Figure 1, "Peak Core Cladding Temperature

Calculated

by ORIGEN" and Figure 2, "Peak Core Cladding Temperature

Calculated

by ANS 5.1" 4. List of Recently Issued NRC Information

Notices Reference: "American

National Standard for Decay Heat Power in Light Water American Nuclear Society Standards

Committee

Working Group, ANS August 29, 1979.Reactors," 5.1, Approved*See previous concurrence

Tech Editor reviewed and concurred

on 03/19/96 DOCUMENT NAME: 96-39. IN To eceiw a copy of this document, hdMcata In the box: 'C' -Copy wlo attechmentenclosure

E' -Copy w/attachment/.nclosure

W -No copy"""7 OFFICE TECH CONTS I C:PECB:DRPM

I I 1II NAME WLJensen*

AEChaffee*

m lJLBirmingham*

C ,v_, DATE 04/02/96 05/16/96 07/1 /96 1 1 03/19/96 1 [ 1 1 __

IN 96-xx July xx, 1996 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.Brian K. Grimes, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: W. L. Jensen, NRR (301) 415-2856 Internet:wlj~nrc.gov

J. L. Birmingham, NRR (301) 415-2829 Internet:jlb4enrc.gov

Attachments:

1. Table 1, "Decay Heat Options Using ANS 5.1, 1979" 2. Table 2, "Relative

Importance

of Options 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) After Reactor Shutdown" 3. Figure 1, "Peak Core Cladding Temperature

Calculated

by ORIGEN" and Figure 2, "Peak Core Cladding Temperature

Calculated

by ANS 5.1" 5. List of Recently Issued NRC Information

Notices Reference: "American

National Standard for Decay Heat Power in Light Water Reactors," American Nuclear Society Standards

Committee

Working Group ANS 5.1, Approved August 29, 1979.*See previous concurrence

OFFICE SASG:DSSA:NRR

SASG:DSSA:NRR

l D/DSSA:NRR

NAME l WLJensen*

RCaruso* l GMHolahan*

DATE 04/02/96 04/04/96 04/30/96 OFFICE TECHED:RPB

1 PECB:DRPM:NRR

_ C/PECB:DRPM:NRR

AD/DRPM:NRR

NAME B. Calure* JBirmingham*

AEChaffee*

BKGrimes DATE 03/19/96 103/19/96

1 05/16/96 1 / /96 OFFICIAL DOCUMENT NAME: G:\JLB\DKAY4.IN

m,4A

IN 96-xx June xx, 1996 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.Brian K. Grimes, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: W. L. Jensen, NRR (301) 415-2856 Internet:wljenrc.gov

J. L. Birmingham, NRR (301) 415-2829 Internet:jlb4@nrc.gov

Attachments:

1. Table 1, Decay Heat Options Using ANS 5.1, 1979." 2. Table 2, Relative Importance

of Options 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) After Reactor Shutdown'3. Figure 1, "Peak Core Cladding Temperature

Calculated

by ORIGEN." 4. Figure 2, 'Peak Core Cladding Temperature

Calculated

by ANS 5.1.'5. List of Recently Issued NRC Information

Notices Reference:

American National Standard for Decay Heat Power in Light Water Reactors," American Nuclear Society Standards

Committee

Working Group ANS 5.1, Approved August 29, 1979.*Sep nrpvious concurrence

OFFICE SASG:DSSA:NRR

SASG:DSSA:NRR

D/DSSA:NRR

NAME WLJensen*

RCaruso* GMHolahan*

nATF 0a4/02/96 04/04/96 04/30/96_.-OFFICE TECHED:RPB

PECB:DRPM:NRR

C/PECB:DRPM:NRR

AD/DRPM:NRR

NAME B. Calure* JBirmingham*

AEChaffeeX

BKGrimes DATE 03/19/96 .03/19/96 .05//b/96 1 05/ /96)FFICIAL DOCUMENT NAME: G:\JLb\UKAY4.IN

mtEA,

K-,-IN 96-xx May xx, 1996 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.Brian K. Grimes, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: W. L. Jensen, NRR (301) 415-2856 Internet:wl

jnrc.gov J. L. Birmingham, NRR (301) 415-2829 Internet:jlb4@nrc.gov

Attachments:

1. Table 1, "Decay Heat Options Using ANS 5.1, 1979." 2. Table 2, "Relative

Importance

of Options 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) After Reactor Shutdown'3. Figure 1, *Peak Core Cladding Temperature

Calculated

by ORIGEN." 4. Figure 2, "Peak Core Cladding Temperature

Calculated

by ANS 5.1." 5. List of Recently Issued NRC Information

Notices Reference:

'American

National Standard for Decay Heat Power in Light Water Reactors," American Nuclear Society Standards

Committee

Working Group ANS 5.1, Approved August 29, 1979.*Sge ntrvinut concurrence

OFFICE SASG:DSSA:NRR

SASG:DSSA:NRR

D/DSSA:NRR

NAME WLJensen*

RCaruso* GMHolahan*

DATE 4T\1o 04/02/96 04/04/96 04/30/96 OFFICE TECHED:RPB

1 PECB:DRPM:NRR

CAE A AD/DRPM:NRR

NAME B B. Calure* JBirmingham*

AE a fel BKGrimes DATE l 03/19/96 03/19/96 0 5/14/96 ; 05/ /96-rr .. ---r ... --.~. -t -.gA I JFIHUAL WLUMNI KAM: U: \-JLt1\UA1Uq.

IN AV0en&

K>-IN 96-xx May xx, 1996 This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please conta t one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager.Brian K. Grimes, Acting Dire or Division of Reactor Progra Management

Office of Nuclear Reacto egulation Technical

contacts:

W. L. Jensen, NRR (301) 415-2856 Internet:wlj@nrc.gov

J. L. Birmingham, NRR (301) 415-2829 Internet:jlb4@nrc.gov

Attachments:

1. Table 1, "Decay Heat Options Using ANS 5 , 1979." 2. Table 2, 'Relative

Importance

of Option 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) Aft Reactor Shutdown." 3. Figure 1, "Peak Core Cladding Temper ure Calculated

by ORIGEN." 4. Figure 2, 'Peak Core Cladding Tegmp ature Calculated

by ANS 5.1.'5. List of Recently Issued NRC 19o( ation Notices Reference:

'American

National Standard fg ecay Heat Power in Light Water Reactors," American Nuclear Society Sta d ds Committee

Working Group ANS 5.1, Approved August 29, 1979.*See previous concu e OFFICE SASG:DA:NRR

SASG:DSSA:NRR

D/DSSA:NRR

NAME WLJfaen* I RCaruso* GMHolahan*

DATE I 04 2/96 1 04/04/96 I 04/30/96.1. .. .*OFFICE f ECHED:RPB

PECB:DRPM:NRR

C/PECB:DRPM:NRR

AD/DRPM:NRR

NAME- / B. Calure* JBirmingham*

AEChaffee

BKGrimes DATE / 03/19/96 03/19/96 05/ /96 05/ /96 bew Tl Ir-luzT l u .s .. -1 -1 %vV UFFIGJAL UDUMEIN NAME: W \)Lb \UKAY4. 11 &W

IN 96-xx May xx, 1996 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.Brian K. Grimes, Acting Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: W. L. Jensen, NRR (301) 415-2856 Internet:wlj@nrc.gov

J. L. Birmingham, NRR (301) 415-2829 Internet:jlb4@nrc.gov

Attachments:

1. Table 1, "Decay Heat Options Using ANS 5.1, 1979." 2. Table 2, wRelative

Importance

of Options 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) After Reactor Shutdown.'

3. Figure 1, wPeak Core Cladding Temperature

Calculated

by ORIGEN.3 4. Figure 2, uPeak Core Cladding Temperature

Calculated

by ANS 5.1." 5. List of Recently Issued NRC Information

Notices Reference: "American

National Standard for Decay Heat Power in Light Water Reactors," American Nuclear Society Standards

Committee

Working Group ANS 5.1, Approved August 29, 1979.A*See Drevious concurrence

OFFICE SASG:DSSA:NRR

SASG:DSSA:NRR

D1XaS.a NAME W W ensen RCaruso k M -ahan DATE 04/02/96 04/04/96 i4/ 0/96 OFFICE TECHED:RPB

PECB:DRPM:NRR

C/PECB:DRPM:NRR

D/DRPM:NRR

NAME B. Calure* JBirmingham*

AEChaffee

DLCrutchfield

DATE 1 03/19/96 03/19/96 1 04/ /96 j 04/ /96 UN ILIAL UL r *:- W..DtuF in WFICIAL UUCUMMN NAM: U: XJLt$UKU>Y4.

IrN

IN 96-xx April xx, 1996 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.Denni .Crutchfield, Director Division f Reactor Program Management

Office of lear Reactor Regulation

Technical

contacts:

W. L. Jensen, NRR (301) 415-2856 Internet:wlj~nrc.gov

J. L. Birmingham, NRR (301) 415-2829 Internet:jlb4@nrc.gov

Attachments:

1. Table 1, Decay Heat Options Using ANS 5.1, 1979.0 2. Table 2, "Relative

Importance

of Options 7200 Seconds (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) After Reactor Shutdown." 3. Figure 1, NPeak Core Cladding Temperature

Calculated

by ORIGEN." 4. Figure 2, "Peak Core Cladding Temperature

Calculated

by ANS 5.1." 5. List of Recently Issued NRC Information

Notices Reference:

American National Standard for Decay Heat Power in Light Water Reactors," American Nuclear Society Standards

Committee

Working Group ANS 5.1, Approved August 29, 1979.*See previous concurrence

OFFICE SASG:DSSA!RR

SASQ: PSSA:NRR D/DSSA:NRR

NAME jW Jenkeg( RCaJ & GMHolahan DATE I 04/2 /96 I 04/10/96 I 04/ /96 OFFICE TECHED:RPB

PECB:DhPM:NRR

C/PECB:DRPM:NRR

D/DRPM:NRR

NAME B. Calure* JBirmingham*

AEChaffee

DLCrutchfield

DATE 03/19/96 03/19/96 04/ /96 04/ /96 FFICIAL DOCUMENT NAME: G:\JLB\UKAY4.IN

5. List of RecentlySosued

NRC Information

Notices Reference:

1. "American

National Standard for Decay Heat Power in Light Water Reactors," American Nuclear Society Standards

Committee

Working Group ANS 5.1. Approved August 29. 1979.OFFICE SASG:DSSA:NRR

SASG:DSSA:NRR

D/DSSA:NRR

NAME WLJensen RCaruso GMHolahan DATE 03/ /96 03/ /96 03/ /96 03/ /96 OFFICE TECHED:RPB

PECB:DRPM:NRR

C/PECB:DRPM:NRR

D/DRPM:NRR

NAME JBirmingham

AEChaffee

DLCrutchfield

DATE 03//7/96 03/ /96 03/ /96 03/ /96 OFFICIAL DOCUMENT NAME: G:\JLB\DECAY

HT.JLB