ML20002D090

Forwards Requests for Addl Info in Support of Proposed Change 13 Re Insertion of Six High Performance Fuel Bundles in Reactor

ML20002D090
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	09/25/1967
From:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
To:	Haueter R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
References
NUDOCS 8101190410
Download: ML20002D090 (11)

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DIS L B'JTION:

Suppl.

DP1 Reading Branch Reading D. J. Skovholt, DPL ACRS Fom Ltr. (/Q Fornal J. Shea, DRL-S. levine, DRL I?EG & A 6tv0-fabh'L DocwniG Soc 'n Docket No. 50-155 pt.25,lk 7 Consumers Power Conpany 218 West Michigan Avenue Jackson, Michigan 149201 Attention: Mr. Pcbert L. Haueter Assistant Electric Production Superintendent Gentlemen:

As a result of your discussions with the ACRS and the Division of Peacter Licensing earlier this month concerning insertion of 6 high perforfrance fuel bundles in the Big Rock Point Reactor, it has been determined that additional infomation is needed in ort.ler to pemit a continuation of review of the proposed operation.

Inclosed is a list of infomation which should be provided as a topplement to your proposed Change No.13 dated May 26, 1967.

Sincerely yous,

/s/

Peter A. Morris, Director Division of Reactor Liceising Dx:losure:

Required hformation

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%rs e September 25, 1967 4N REPLY REFER To:

Eocket No. 50-155 i

Consumers Pcwer Company 218 West Michigan Avenue Jackson, Michigan 49201 Attention: Mr. Robert L. Haueter Assistant Electric Production Superintendent Gentlemen:

As a result of your discussions with the ACRS and the Division of Reactor Licensing earlier this month concerning insertion of 6 high perfonnance fuel bundles in the Big Rock Point Reactor, it has been detennined that additional inferration is needed in order to pennit a continuation of

.j review of the proposed operation.

Enclosed is a list of inforration which should be provided as a supplement to your proposed Change No. 13 dated May 26, 1967.

Sincerely yours, e k d. M Peter A. Morris, Director Division of Reactor Licensing

Enclosure:

1 Required information I

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REQUEST FOR ADDITIONAL INF0FPATION 1.

Provide a brief sumary of the experiments and the calculations which justify the assumed fuel failure threshold. The discussion should consider recent ANL results and potential diffem nces between pellet and vibratory cmpacted fuel, also the effects of burnup. You are asked to:

(a) Describe the assumed course of events when a fuel pin maches and exceeds this threshold. For those cases during which steam may be generated, estimate the energy deposited in this sink, the pressure history, volume affected and time duration.

(b) Expand (a) to the deceription of the course of events in a fuel bundle when at least some of the pins exceed this threshold..Two cases seem pertinent; these are (i) with coolant flowing and (ii) with coolant stagnant.

(c) Consider (b) for the case of a bundle containing high perfomance fuel pins (with the geometry of the proposed Big Rock experiments).

Compare this to the case of a standard fuel bundle.

2.

Assume a control rod failure which inserts reactivity in an amount which could cause a maximum energy density in a high perfonrance fuel pin of 450 cal /gm. Please follow the course of the accident, at least se:ri-quantitatively, until the power drops subsequent to insertion of available zwactivity, and until the pressure drops to a low value.

Insofar as possible, use realistic assumptions with an indication of uncertainties at each step. Estifrate the radiation doses at the site boundary. Analysis should be perfomed for both hot standby and power conditions. State the reactivity insertion rate and delta k required.

Give fractions of the core at different energy densities. Consider both pellet and vibratory compacted fuel. Pm sent the results assuming fuel failum thresholds of 235, 290, 330 and 425 cal /gm. Also, state the msults for the cases where the control rod has a delta k value of 0.8%

and for intermediate values, such as 1.2 and 2.0%.

Include at least one value which leads to an energy density of approximately 350 cal /gm with an assumed failum threshold of 330 cal /gm. What measures in addition to administrative procedures might be used to reduce the possible reactivity insertion rates? What will be the maximum uncertainty in rod worth?

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g 3.

Does the presence of the high perfomance fuel pins and bundles cause the postulated reactivity accident to be more or less severe? Pleasc discuss. For reactivity transients, including the rod ejection accident, discuss the effects of possible pressure pulses. Consider the effects of steam explosions when the fuel fails and is dispersed in the coolant and also when intimate mixing of fuel and water occurs as a result of water rushing back following its initial expulsion. Evaluate the effects relative to possible damage to the core, core spray system and the reactor pressure vessel.

4 In analyses of strong reactivity transients, consider the cases where the reactor is initially at hot standby and at power. What is assumed to terminate the accident? Why? Discuss such accidents, assuming contml rod insertion is delayed and does not terminate their course.

Give the basis for assumed shutdown mechanisms other than Doppler.

Discuss relative timing of various effects. What is the effect on the course of accidents if the Doppler effect is 20% less than the value used. Justify use of 1

dependence of the Doppler coefficient.

5. Discuss possible reactivity effects during reactivity transients of the following:

(a) Motion of molten fuel in fuel rods (b) Bowing or other notion of fuel rods (c) Chilling of fuel (and resultant positive Doppler effect) when it is dispersed or mixed in the coolant.

6.

Discuss the possible (unintentional) reactivity insertion rates ard total possible (unintentional) reactivity changes. Include disc.ussion of the probability of occurrence of the more extreme cases.

7.

Prepare a study to show the maximum fuel pin temperatures as a function of pipe break size. Results should show temperatures for normal as well as for the special centermelt pins. Of interest also is the total enthalpy of both types of fuel bundles as a function of break size. Please use zealistic assumptions and estimate uncertainties at each step. What would be the results :Lf conservative assumptions and parameters are used at each step in the analysis? Estimate the radiation doses at the site bourdary for these conditions. Describe the state of the fuel and cladding for the bundle containing the hottest pins. If some of these pins are thought to fail, attempt to describe the course of events, and, if appropriate, any altered hazard to the health and safety of the public.

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8. Is them a criterion for maximum remissible central meltihg? What is its basis?

9.

It is understood that studies are undensay concerning an up-grading of the emergency core cooling system of the Big Rock Point Reactor.

- What is the contemplated timing of improvements which may be suggested by these studies? Can significant impmve: rents in the emergency core cooling system be made in connection with institution of the centenrelt program?

10. Please provide a brief description of the calculational model used to correlate fuel pin behavior to extrapolate to new conditions. Does the same model correlate pellet and powder fuel? khich sets of pins in the pmposed Big Rock experiments am nost appropriate to new reactor designs and which are designed as further proof-tests of existing desiens?

11. Propose appropriate tecnnical specitications reganiing administrative and procedural controls that will be effected while the high perfomance fuel is in the reactor. These specifications should include:

(a) Actions to be taken in the event of detected or suspected primry system leaks.

(b) Notification and appravals that will be required for reactor start-ups, including start-ups following scrams.

(c) Requirements for the pasence of technical specialists during start-ups, power increases or other significant operating events.

12. Discuss the details of the inspection program for the experimental fuel and indicate how this inspection pmgram will enhance the continued safe operation of the fuel. This discussion should include:

(a) The types of inspections, destructive and non-destructive tests that will be perfonred.

(b) The frequency and/or schedule for each of the above.

(c) The limits, where appropriate, that must be met in order for con-tinued operation of the fuel in the reactor to take place.

(d) An assurance that at least one set of destructive tests will be perfomed and evaluated prior to approaching fuel irradiation of 1.

10,000 MWD /T.

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13. Discuss a loss of generator accident in which the electric generator

-loses its load with and without autmatic opening of the turbine bypass valve. Assume coolant meirculation electric pcrer is lost.

Show reacter power, centermelt fuel peak heat flux, peak center fuel temperatums, peak clad temperatures, critical heat flux ratio and centemelt fuel bundle coolant flow vs time after the accident in contrast to the (theoretical hot fuel) conditions in the core with-out the centemelt fuel bundles inserted.

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DISTRIBUTION:

Suppl.

DRL Reading Branch Reading D. J. Skovholt, DRL ACRS Form Ltr Forral J. Shea, DRL S. Levine, DRL Dock (t No. 50-155

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Consumers Ibdr Company 218 West Michigan Avenue

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Jackson, Michigan 149201 Attention: Mr. Ro L. Ilaueter Assistant ectric Pmd tion Superint t

Gentlemen:

As indicated by the Chairman o -

ACRS, following the oral pre-sentation to justify insertion 6 high perfomance fuel burdles in 'Ibe Big Rock Point cme by Power Company and General Electric Cmpany reIresentatpes on ptember 7,1967, the comnittee requiess additional informa, tion in to pemit a continuation of comnittee review of sed operat We have added our reque for additional tion, previously discussed with your resentatives on Sept 6, 1967, to that

.epared by the ACRS Enclosed is a copy f the list of information whic should be pro-vided in writing.

Sincerely yours, i

Donald J. Skovholt Assistant irrector for Reactor Operations Division of Reactor Licensing Eh4 Enclosures I,ist DRL M

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REOUFSr FOR ADDITIONAL INFORMATION r

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/' ',IProvide a brief sumnary of the experiments and the calculations which justify the assumed fuel failum threshold. 'Ihe discussion should ccrisider mcent ANL results and potential diffemnces between pellet ard vlbmtory ccrn; acted fuel, also the effects of burnup. Ycu are i

asked to:

(a) Describe the assumed course of events when a fuel pin maches and exceeds this threshold. For those cases during which steam may be generated, estimate the energy deposited in this sink, the pressure history, volume affected and time duration.

(b) Expand (a) to the description of the course of events in a fuel bundle when at least some of the pins exceed this threshold. Two i

cases seem pertinent; these are (i) with coolant flowing and (ii) with coolant stagnant.

(c) Consider (b) for the case of a bundle containing high performance fuel pins (with the geometry of the proposed Big Fock experiments).

Conpare this to the case of a standarti fuel bundle.

,,1d Assume a contml red failure which inserts reactivity in an arount which

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could cav-: a maxirum energy density in a high perfonnance fuel pin of I

450 ca3/F;n. Please follow the course of the accident, at least semi-quanti:atively, until the power dmps subsequent to insertion of availaile reactivity, ard until the pressure drops to a low value.

Insofar as possible, use realistic assunptions with an indication of uncertainties at each step. Estimate the radiation doses at the site i

coundary. Analysis should be perfomed for both hot standby and power conditions. State the reactivity insertion rate and delta k required.

i Give fmetions of the core at different energy densities. Consider both pellet and vibrator'y corpacted fuel. Pasent the results assuming fuel failure thresholds of 235, 290, 330 and 425 cal /gm. Also, state the j

results for the cases where the control rod has a delta k value of 0.8%

and for interinediate values, such as 1.2 and 2.0%.

Include at least one l

value which leads to an energy density of approximately 350 cal /gm with an assumed failure threshold of 330 cal /gm. What measums in addition to administrative procedures might be used to reduce the possible reactivity insertion rates? What will be the maxinum uncertainty in md worth?

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Does the presence of the high performance fuel pins ard bundles cause q

the postulated mactivity accident to be more or less severe?. lease discuss. For reactivity tmnsients, including the md ejection accident, discuss the effects of possible pressum pulses. Consider the effects of steam explosions when the fuel fails and is diapersed in the coolant and also when intimate mixing of fuel and water occurs as a result of water mshing back following its initial expulsion. Evaluate the effects relative to possible damage to the core, com spray system and the reactor pressure vessel.

g.[ g In analyses of stmng mactivity transients, consider the cases where the reactor is initially at hot standby and at power. What is assumed to teminate the accident? Why? Discuss such accidents, assuming contml md insertion is delayed and does not teminate their course.

Give the basis for assuned shutdown mechanisms other than Doppler.

Discuss relative timing of various effects. What is the effect on the course of accidents if the Doppler effect is 20% less than the value used. Justify use of 1

dependence of the Doppler coefficient.

.W T 1

/ / Discuss possible reactivity effects during reactivity transients of the following:

(a) Motion of molten fuel in fuel mds i

(b) Bowing or other motion of fuel mds (c) Chilling of fuel (and resultar.t positive Doppler effect) den it is dispersed or mixed in the coolant.

G p Discuss the possible (unintentional) reactivity insertion rates and total possible (unintentional) reactivity changes. Inchde discussion of tre i

probability of occurtence of the mom extreme cases.

'7 Ad Pmp a study to h the mime fuel pin temperatures as a function of pipe break size. Pesults should show temperatures for normal as well as for the special centertnelt pins. Of interest also is the total enthalpy of both types of fuel bundles as a function of break size. Please use l

realistic assuiptions and estimate uncertainties at each step. What would be the results of conservative assumptions and parameters are used at l

each step in the analysis? Estimate the rediation doses at the site bourdary for these conditions. Describe the state of the fuel and clam 4g for the bundle containing the hottest pins. If some of these pins are thought to fail, attempt to describe the course of events, and, if j

apptppriate, any altered hazard to the health and safety of the public.

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7 Is them a criterion for maxinum pemissible central melting? What i

is its basis? h vide & N d4b i;.sp^ctim,mm h the j

fuel te i ras sef wetivn ef the fuel in the -tm i

J[ g It is underttood that studies an undemay conceming an up-grading of the emergency com cooling system of the Kig Rock Ibint Peactor.

l What is the cmtemplated timing of impmvements which may be suggested bs/ these studies? Can significant impmvements in the energency core cooling system be made in connection with institution of the centemelt program?

b )<1tf Please provide a breif description of the calculational nodel used to corm late fuel pin behavior to extrapolate to new conditions. Does l

l the same model correlate pellet and power fuel? Which sets of pins in the pmposed Big Rock experiments am nest appropriate to new i

mactor designs and which are designed as further proof-tests of j

existing designs?

i y g Propose appropriate technical specifications regarding administrative i

and procedu..d controls that wi-1 be effected while the high perfonnance fuel is in tl.. reactor. These specifications should include:

(a) Actions to be taken in the event of detected or suspected prirej system leaks.

(b) Notification and approvals that will be required for reactor start-ups, including start-ups following scrams.

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(c) Requirements for the presence of technical specialists during start-ups, power inemases or other significant opemting events.

4 Discuss the details of the inspection program for the experimental fuel l

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i" and indicate how this inspection program will enhance the continued i

safe operation of the fuel. This discussicn shculd include:

l (a) The types of inspections, desetuctive and nco-deseructive tests that will be performed.

s (b) The fm quency and/or schedule for each of the above.

(c) The lilaits, whem appropriate, that nust be met in order for con-tinued opemtion of the fuel in the mactor to take place.

(d) An atit;urance that at least one set of destmetive tests will be perfomed and evaluated prior to approaching fuel irradiation of j

10,000 MWD /T.

i 44 j

[7 Discuss a loss of generator accident in which the atlectric generator loses its load with and without automatic opening of the turbine i

bypass valve. Assume c%lant zweirculation electri: power is lost.

Show reactor power, cenwmit fuel peak heat flux, peak center i

fuel temperatures, peak cleo :emperatures, critical heat flux ratio i

and centermelt fuel bundle coolant flow vs time after the accident f

in contraut to the (theoretical hot fuel) conditions in the cort with-1 out the cantermelt fuel bundles inserted.

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