ML19343C375

Generic Info for Barrier Fuel Demonstration Bundle Licensing, Approved Version

ML19343C375
Person / Time
Site:	Quad Cities
Issue date:	02/28/1981
From:	GENERAL ELECTRIC CO.
To:
Shared Package
ML19343C374	List: ML19343C373 ML19343C375
References
81NED253, NEDO-24259-A, NUDOCS 8103230527
Download: ML19343C375 (180)

Text

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ - - - . -

O O'::

CLASSI FEBRUARY 1981 f GENERIC INFORMATION FOR BARRIER FUEL DEMONSTRATION

, BUNDLE LICENSING l l  ;

1 '

l '

l l

l l i l

l l

l l

i g g g gg GENER AL h ELECTRIC

P~

NED0-24259-A 81NED253 Class I February 1981 GENERIC INFORMATION FOR BARRIER FUEL DEMONSTRATION BUNDLE LICENSING .

(The Nuclear Regulatory Commission's Acceptance Letter and Report Evaluation are included.)

l l

NUCLEAR POWER SYSTEMS DIVISION e GENERAL ELECTRIC COMPANY SAN JOSE, CALIFORN! A 95125 GENER AL $ ELECTRIC

I DISCLAIMER OF RESPONSIBILITY

. This document was prepared by or for the General Electric Company, Neither the General Electric Company nor any of the contnbutors to this document:

A. Makes any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the information containedin this docu-ment, or that the use of any information disclosed in this document may not ininnge privately owned rights; or B. Assumes any responsibulary for liability or damage of any kind which may result from the use of any information disclosed in this document.

l l

l l

l l

l I

NEDO-24259-A

1. o UNITED STATES

((>e, g g NUCLEAR REGULATORY COMMISSION W ASHINGTON, D. C. 20555

, L j k.v ...

,o# NOV 121990 MFN -203 -80 General Electric Company 1TTN: R. E. Engel, Manager Reload Fuel Licensing Safety and Licensing Operation 175 Curtner Avenue Su n Jose, California 95125

SUBJECT:

ACCEPTANCE FOR REFERENCING TOPICAL REPORT NED0-24259 " GENERIC INFORMATION FOR BARRIER FUEL DEMONSTRATION BUNDLE LICENSING" The Nuclear Regulatory Commission has completed its review of the General Electric Company Licensing Topical Report Number NEDO-24259 entitled

" Generic Information for Barrier Fuel Demonstration Bundle 'icensing" including the additional information transmitted in your September 11, 1980 letter. The topical report provides information on a proposed large scale (132 bundles) demonstration irradiation (in Quad Cities Unit 2) of PCI-resistant BWR fuel rods containing " barrier" cladding (consisting of a high priority zirconium liner metallurgically bonded to the Zircaloy-2 cladding. The summary of our evaluation is attached.

As a result of our review, we generally concluded that topical report NEDO-24259, as modified to incorporate the information supplied in response to staff questions, serves as an acceptable reference that provides a generic description of the demonstration program. And, based on the information provided, we believe that the PCI barrier fuel demon-stration is licensable, pending the review and approval of a reload appli-cation to be submitted by the Quad Cities Unit 2 licensee. We expect that submittal to provide certain specific information and comitments that have not been received during the course of the topical report review, viz., (a) a detailed operating plan for the demonstration, (b) a comitment to perform on-line monitoring and post-irradiation examinations (of a kind consistent with GE recommendations contained in response to staff question 231.2--see attached SER), and (c) other information traditionally submitt1d in fuel reload applications (such as physics and thermal-hydraulic analytical results).

iii

WEDO-24259-A l i

WCV 2 Es.

Mr. R. E. Engel i

Since, as stated in Section 1.1 Scope of the topical report, " Licensing of the specific core including the special operating procedures of the demonstration will occur as a part of the normal reload licensing effort,"

we do not anticipate any significant problems in acquiring the needed additional information and commitments prior to loading of the demonstration bundles.

We do not intend to repeat the review of the safety features described in the topical report and found acceptable in the attachment. Our acceptance applies only to the features described in the topical report and under the conditions discussed in the attachment.

In accordance with established procedure, it is requested that General Electric Company publish an approved version of this report, incorporating the information provided in your letter of September 11, 1980, within three months of receipt of this letter. The revision is to incorporate this letter and the attached topical report evaluation following the title t page and thus just in front of the abstract. The report identifications of the approved reports are to have a -A suffix.

Should Nuclear Regulatory Commission criteria or regulations change such that our conclusions as to the acceptability of the report are invalidated, General Electric Company and/or the applicants referencing the topical report will be expected to revise and resubmit their respective documen-tation or submit justification for the contir~cd effective applicability of the topical report without revision of their respective documentation.

Sincerely, 8 W Robert L. Tedesco, Assistant Director for Licensing Division of Licensing

Enclosure:

Topical Report Evaluation IV

I

- NEDO-24259-A TOPICAL REPORT EVALUATION Report Number: NE00-24259 Repor t

Title:

Generic Information for Barrier Fuel Demonstration Bundle Licensing Report Date: May 1980 Originating Organization: General Electric Company Reviewed By: Reactor Fuels Section, Core Performance Branch, Division of Systems Integration, October 1980 Sumary of Topical Report The topical report is intended to provide a basis for licensing " barrier" fuel bundles to be used in a demonstration irradiation of pellet / cladding interaction (PCI)-resistant BWR fuel. The planned demonstration involves a large-scale (132 bundles) irradiation in Unit 2 of the Quad Cities Nuclear Power Station, starting with Cycle 6 (Ref.1). It is proposed that about half (64) of the 132 bundles would be power ramped, in groups of 16; i.e., one group of 16 would be ramped at the end of each cf four successive reactor cycles.

The term " barrier fuel" ctems from the use of a 0.003-inch thick, high purity zirconium liner, i.e., barrier, whicn is metallurgically bonded to the zircaloy-2, structural part, of the fuel rod cladding. The dimensions of the fuel rods and the mechanical design of the fuel bundle are the same as the current GE pre-pressurized 8x8 retrofit bundle (P 8x8 R).

As indicated by its title, the topical report provides generic (i.e., conceptual) information on the barrier fuel demonstration, while detailed infomation on the operating procedures, nuclear designs, etc., is to be provided by the licensee in the usual reload-type application. Thus, the topical report contains rather general information on (1) program scope and description, (2) fuel loading and operation, (3) fuel mechanical design and (4) safety analyses. The section on safety analyses, for example, simply refers to the GE generic methods and models for reload fuel safety analyses (Ref. 2), and p ates that (a) those methods and models were found applicable to the barrier fuel, and (b) when the final fuel-loading pattern is established the calculations will be performed and reported for licensing in the same manner as for an ordinary reload core.

Sumary of Regulatory Evaluation During the course of our review of NED0-24259, we issued one formal request for additional infomation (Ref. 3) that was responded to by GE in reference 4.

Following GE's initial formal response, some follow-up questions were raised by v

NEDO-24259-A telephone (Ref. 5). The GE responses to our follow-up questions were transmitted via reference 6. Our formal inquiries and all of the GE responses will be in-corporated into NED0-24259 via amendment.

Ogr. review focused on two factors:

1. The topical report, as submitted, was extremely brief and did not constitute a " stand-alone" referential document. Hence, additional information was requested on the barrier fuels test program structure, test results to date (and how they related to the planned demonstration irradiation in Quad Cities Unit 2), and planned milestone schedules. In addition, some further detail was requested regarding the potential effects of barrier cladding properties on the safety analysis. Responses to those questions (Q 231.1, 231.2 and 231.4) were satisfactorily provided via attachments (Al to A4) to reference 4.

2. We believed there was a special need for adequate failure detection, fuel damage surveillance and analytical PCI failure prediction capability because (a) the planned demonstration irradiation is relatively large-scale, (b) the proposed power ramp feature is unique (i.e., repeated power ramp testing of a new fuel design has not been carried out heretofore in a commercial U. S. power reactor), (c) there is a small, but finite, probability that some rods will fail (particularly during the ramps), and (d) it is desirable to obtain as much potentially useful information from the demonstration as practicable in preparation for future potential reload applications. Although initial responses (Ref. 4) to our request for additional information (Q 231.3) on fuel failure detection capaoility, post-irradiation examination, and PCI failure prediction were not totally satisfactory, sufficient information was provided later (Ref. 6). The substance of these issues is discussed below.

Fuel Failure Detection The topical report, as submitted, contained no information on fuel failure detection capability at Quad Cities Unit 2. Since the barrier fuel demonstration is intended to provide information "which will lead to valid engineering conclusions" regarding the PCI resistance of the design, we believed that it was necessary to determine not only the capability of the failure detection instrumentation at Quad Cities Unit 2, but also the ability to correlate the activity monitor readings with the number and/or location of leaking fuel rods. In addition, the time of failure vi

NED0-24259-A (i.e., moment at which failure occurs) is significant because it may be related to the magnitude of the power ramp or ramp rate. This point is particularly significant in tems of the relative PCI resistance of the barrier fuel as compared with standard design fuel.

I response to our inquiry, GE indicated (Ref. 6) that current on-line activity monitoring capability at Quad Cities Unit 2 consists of a gama-ray detector (located at the steam jet air ejector) that can detect changes in gama-ray intensity within 2 to 5 minutes of changes in the core offgas (e.g., fuel failures), while inferences regarding the numbers of fuel rods failed in any time increcent are now made by isotopic analyses of gas and coolant water samples.

Thus, the gama-ray detector near the steam jet air ejector can be used to initiate a sampling sequence which can then yield an estimate of the number of failed fuel rods.

GE further asserted in response to this question that "therr: is no direct calibra-tion to link total gama-ray intensity with the number of f ailed fuel rods."

As noted in a recent GE paper (Ref. 7) on BWR fuel perfomance, however, " typically, incremental activity values of approximately 3,000 uCi/sec above background measured at the steam jet air ejector are equivalent to one leaker bundle."

Thus, while GE expects the offgas activity at the time of the first demonstration ramp (near end of cycle 6) to be about 55,000 uCi/sec, and while it is stated (Ref. 6) that "it is conservatively estimated that failure of less than 10 fuel rods could be rapidly detected" (emphasis added), it would appear from reference 7 that the sensitivity of the measurement should provide significantly higher precision than that.

Therefore, we believe the detection capability exists at Quad Cities 2, and we will expect the licensee's reload application for the barrier fuel to address the operating plan for evaluation of the . aber of failed fuel rods (if any) caused by each incremental movement of each ramp cell control blade during the planned power ramps. We will further expect that the results of the faflure detection

- be reported to NRC in a timely way, even if the activity values do not exceed technical specification limits.

vii

l NEDO-24259-A Post-Irradiation Examination The topical report, as submitted, did not contain any information on (a) the post-irradiation examination (PIE) program to be undertaken on discharged demon-stration bundles or (b) any interim examinations that would be performed during rWueling outages. However, in view of the stated goal of the program to obtain information that will lead to valid engineering conclusions, it is obvious that such examinations are central to attainment of that objective.

In its initial response (Ref. 4) to our request for information on this matter, GE pointed out that the demonstration program has been structured only through

" PHASE 2," which includes the first two power ramps (through Cycle 7) and that the question of PIE of discharged bundles had been deferred to PHASE 3, the scope of which had yet to be determined. Subsequently (Ref. 6), GE indicated that it will recomend to the licensee that all barrier fuel assemblies that are ramped in a given cycle be sipped along with any buffer fuel assemblies which are scheduled to be returned to the core for additional irradiation. GE also indicated that it will recomend examination of discharged demonstration fuel to assess its condition, including the possible presence of incipient defects.

In view of the objectives and unique features of the demonstration, we believe the proposed GE fuel surveillance recommendations are appropriate. We believe further that the proposed recomendations will not impose any unique or unexpected requirement on the licensee since, as asserted by GE (Ref. 7), "over the years sipping has been shown to be a highly effective means for identifying leaker bundles and is used by all BWR utilities."

Accordingly, we will expec+ the licensee's reload application to address the PIE plan and to comit to performing fuel surveillance consistent with the GE recomendations noted above. We will expect the results of such examinations to be reported to NRC in a timely way.

PCI Failure Prediction With regard to PCI failure prediction, it is GE's position that a reliable analytical model for accurate prediction of PCI failure probabilities does not presently exist (Ref. 4). However, in attachment A2 to reference 4, GE provided viii

.' NEDO-24259-A ramp test data for both standard (non-barrier) fuel and Zr-liner barrier fuel.

Those data defined a so-called failt.re threshold as well as a 100% failure range for the non-barrier fuel. (Barrier fuel tested in the same range of peak powers did not fail.) Since the demonstration ramps are designed so that the fuel in the ramp cells will be ramped to power levels above the failure threshold curve for non-barrier fuel, but where barrier fuel did not fail in test reactor ramps, there is thus a means for determining the relative risk. Quantitative (and conservative) estimates of PCI failure probability, in addition, can be made with independent codes, such as PROFIT (Ref. 8).

Regulatory Position We have completed our review of topical report NEDO-24259, which provides generic infomation for a demonstration irradiation of Zr-liner, PCI-resistant, barrier fuel in Unit 2 of the Quad Cities Nuclear Power Station, and which is intended to provide a basis for licensing. Based on our evaluation of the infomation provided in the topical report and in the responses to our requests for additional information, we conclude that the report, as modified to incorporate that additional infomation, serves as an acceptable reference and generic description of the planned demonstration. We further conclude that the PCI barrier fuel i demonstration is licensable, pending our review and approval of a reload applica-tion to be submitted by the Quad Cities Unit 2 licensee, and that the substitution of Zr-liner barrier fuel for standard (P 8x8 R) fue, in Unit 2 of the Quad Cities Nuclear Power Station will result in negligible changes in safety margins or reliability compared to the reference P 8x8 R core.

We will, however, expect the reload application to provide certain specific information and consnitments as follows:

1. A detailed operating plan for the demonstration.

2. A comitment to perfom on-line monitoring and post-irradiation examinations of a kind consistent with proposed GE recomendations contained in the responses to staff questions.

3. Other information traditionally submitted in fuel reload applictions (such as physics and themal-hydraulic analytical results).

iX

NEDO-24259-A References

1. R. E. Engel (GE), Letter to Thomas A. Ippolito (NRC), May 15, 1980.

2. " Generic Reload Fuel Application," General Electric Company Report, NEDE-24001-P-A-1 (Proprietary) and NED0-240ll-A-1 (non-Proprietary),

July 1979.

3. Robert L. Tedesco (NRC), Letter to R. E. Engel (GE), August 28, 1980.

4. R. E. Engel (GE), Letter to Robert L. Tedesco (NRC), September 11, 1980.

5. (a) W. V. Johnston, R. O. Meyer, and M. Tokar (NRC), Telecomunication with R. E. Engel, R. Proebstle, et al. (GE), September 26, 1980.

(b) W. V Johnston, R. O. Meyer, and M. Tokar (NRC),Telecomunication with R. E. Engel, C. Hilf, et al. (Gi), September 30, 1980.

6. R. E. Engel (GE), Letter to Robert L. Tedesco (NRC), October 2,1980.

7. W. E. Bailey, J. S. Armijo, J. Jacobson, and R. A. Proebstle, "BWR Fuel Performance," Proceedings of American Nuclear Society Topical Meeting on Light Water Reactor Fuel Perfomance, Portland, Oregon, April 29 - May 3, 1979.

8. P. J. Pankaskie, " Mechanistic Considerations Used in the Development of the PROFIT PCI Failure Model," NUREG/CR-1462, May 1980.

l l

X

NEDO-24259-A CONTENTS I Page NRC ACCEPTANCE LETTER iii NRC TOPICAL REPORT EVALUATION v ABSTRACT xv

1. INTRODUCTION 1-1 1.1 Scope 1-2

2. PROGRAM DESCRIPTION 2-1 2.1 Fuel Loading 2-1 2.2 Operation 2-3

3. FUEL MECHANICAL DESIGN 3-1

4. SAFETY ANALYSES 4-1

5. REFERENCES 5-1 APPENDICES A. RESPONSES TO NRC REQUEST FOR ADDITIONAL INFORMATION A-1 B. ADDITIONAL INFORMATION IN RESPONSE TO REQUEST 231.2 B-1

+

e t

1 4

i xi/xii

NEDO-24259-A ILLUSTRATIONS Figure Title Page 2-1. Cross Section of Fuel Bundle of 2.65% Average Enrichment 2-4

'2-2 Cross Section of Fuel Bundle of 2.65% Average Enrichment 2-5 2-3 Cross Section of Fuel Bundle of 2.97% Average Enrichment 2-6 2-4 Cross Section of Fuel Bundle of 2.83% Average Enrichment 2-7 2-5 Ramp Cell Locations, Cycles 6 and 7 2-8 2-6 Ramp Cell Locations, Cycles 8 and 9 2-9 2-7 Proposed Pre-Ramp Locations for Special Barrier Bundles 2-10 2-8 Operational Strategy 2-11 i

3 9 Typical Axial Power Distribution in a Ramp Cell Bundle for Blade Pull of Six Notches (1.5 ft) 2-12 4

4 4

/ ,

/

xiii/xiv

. -. ~. . . . . _ . . - _ - .- .

NEDO-24259-A ,

I ABSTRACT

. ' A review of the analytical methods used for calculations for ticensing BWR cores using standard fuel bundles indicates j that the methods are suitable for licensing specially  !

designed bundles which uitt be used in a large-seate demonstration of fuel designed to be more resistant to the effecta of peitet-cladding interaction (PCI).

The fuel cladding contains a metallurgically bonded liner of airconium, and the fuel bundles have a specific nuclear design to attou for power increases necessary to demonstrate

. PCI resistance.

e

. eww-*

4 xv/xvi t _

. -. - - -. - . __~= - . _. - --.

i l l

NEDO-24259-A l l

1. INTRODUCTION '

Experience in the nuclear industry with fuel rods of Zircaloy-clad urania has revealed several causes of fuel rod failure. Most of these causes have been cor-

! rected by innovative design modifications and by improvements in manufacturing i processes (References 1 through 4). However, one low level class of fuel failures has yet to be eliminated and is presently mininized by operational methods. l These failures have been attributed to pellet-cladding interaction (PCI).

The incidence of such failures is clos- linn=2 to the power history of the fuel rod and to the magnitude, rate, and duration of power changes.  ;

Pellet-cladding interaction fuel failures have occurred in all types of water-cooled reactors that are fueled with urania which is sheathed in Zircaloy: boiling water reactors (BWR), pressurized water reactors (PWR),

, Canadian deuterium-coderated reactors (CANDU), and the steam generating heavy water reactor (SGHWR).

Pellet-cladding interaction was first identified by General Electric in a BWR plant in 1971. General Electric immediately embarked upon a program to understand the PCI pheno =enon and to develop potential remedies. This effort resulted in a series of design. changes to minimize the frequency of these types of failures.

In early 1972, the 7x7 fuel rod design was improved by reducing the ratio of

, pellet length to diameter, chamfering the pellet ends, eliminating pellet dishing to reduce localized strain, and increasing the cladding heat treatment te=perature to reduce variability in cladding mechanical properties. PCI failures are depen-dent on fuel rod power histories. Rod powers were reduced with the 8x8 fuel design-introduced in the Spring of 1974. The 8x8R fuel design further reduced ,

fuel rod local peaking. In the latest design change, the 8-8R fuel rods were pre-l pressurized to improve gap conductance and thus lower fuel temperatures. This reduction in fuel temperature is equivalent to a reduction in linear power and acts to increase resistance to PCI.

A further innovation has been the development.of " barrier fuels" which have a special fuel cladding designed to protect the Zircaloy sheath from the harmful ,

effects of localized stress and reactive fission products during reactor service. F Considerable testing has been performed on barrier fuels.using either a copper

'l-1

i NEDO-24259-A barrier or a zirconium liner (References 5, 6 and 7). Results have been successful, and a large-scale demonstration of the PCl-resistant fuel is now required in a commercial power reactor.

Among the advantages expected from successful completion of this program and the implementation of PCI-resistant fuel are: increased capacity factor, improved load following capability, reduced occupational exposure at plant sites, and lower offgas rates.

1.1 SCOPE The purpose of this document is to provide a basis for licensing the barrier fuel bundles to be used in a demonstration of PCI-resistant fuel. Current plans are for a demonstration that uses 132 fuel bundles containing barrier cladding. The barrier consists of a high purity zirconium liner metallurgically bonded to the

-Zircaloy-2 cladding.

The schedule for the demonstration requires placing the demonstration fuel bundles into the core of Unit 2 of the Quad Cities Nuclear Power Station as part of a normal reload batch beginning in Cycle 6.

The demonstration is so designed that the PCI resistance of the barrier fuel can be demonstrated by appropriate power increases, while the power changes of the conventional fuel are held within specified limits to prevent affecting its integrity.

With this document, licensing is sought for use of these bundles on a generic basis under normal operating conditions. Licensing of the specific core includ-ing the special operating procedures of the demonstration will occur as a part of the normal reload licensing effort.

1-2

NEDO-24259-A l

2. PROGRAM DESCRIPTION The goal of this program is the demonstration of a PCI-resistant fuel under con-ditions which will lead to valid engineering conclusions. The PCI-resistant fuel selected for demonstration utilizes the barrier concept to protect the fuel cladding from failure caused by PCI. The particular barrier fuel design celected has a fuel sheath, or cladding, which is comprised of Zircaloy-2 and a liner of high purity zirconium metallurgically bonded to the Zircaloy. The zirconium liner is 0.003-in. thick, approximately 10% of the total cladding wall thickness. The dimensions of the fuel rods and the mechanical design of the fuel bundle are the same as the current prepressurized 8x8 D-lattice retrofit bundle (P8x8R).

Major emphasis has been directed at selection and analysis of the fuel loading strategies. The analyses performed include: (1) Haling analysis (Reference 8) to determine cycle exposure capability; (2) reactivity margin checks (hot excess and cold shutdown); (3) stepwise burns through each cycle using critical rod patterns; (4) energy capability comparison between the demonstration fuel cycle schedule and a nominal fuel cycle schedule; (5) core response during the ramping of the PCI-resistant fuel; (6) core response to several assumed accidents; and (7) scram reactivity comparisons.

It is convenient to define the nomenclature that will be used. The cells for which the end of cycle power ramps are planned are called " ramp cells". The 132 bundles of barrier fuel (i.e., the PCI-resistant uel) to be demonstrated are called the " demonstration fuel bundles". Of these, the 64 scheduled for power ramps in the special ramp cells are called "special demonstration bundles" or "special barrier bundles", while the 68 remaining are called " standard demonstra-tion bundles" or " standard barrier bundles".

The special demonstration bundles have nuclear designs which provide the desired power conditions for the power ramping. The demonstration fuel bundles are listed in Table 2-1; the special demonstration bundles are shown in Figures 2-1 through 2-3, and the standard demonstration bundle is shown in Figure 2-4.

2-1

NEDO-24259-A 2.1 FUEL LOADING The 64 special barrier bundles which are scheduled to be power ramped are divided into four groups of 16 as shown in Table 2-1. One group of 16 is to be ramped at the end of each of four successive reactor cycles. Thus, one group is scheduled to be ramped at the end of Cycle 6, another at the end of Cycle 7, etc. In Cycles 6 and 7, the bundles to be ramped are placed into four ramp cells (one cell in each quarter core) as shown in Figure 2-5. In Cycles 8 and 9, there will be eight ramp cells, and it is possible that fresh fuel bundles will have to be used within the ramp cells to boost the power to obtain a good demonstration of PCI resistance during the power ramps. In that event, each quarter core would have two ramp cells, each with two demonstration fuel bundles and two fresh driver fuel bundles as shown in Figure 2-6. The demonstration bundles which are to be ramped in a particular cycle are loaded in the special ramp cells at the beginning of that cycle; bundles which are scheduled to be ramped in subsequent cycles are loaded near the core periphery in the locations indicated in Figure 2-7.

2.2 OPERATION The general operating procedure planned for Cycles 6 through 9 is shown in Figure 2-8. The control blades in the ramp cells are kept at least 60% inserted.

During this portion of the cycle, the power is kept low through proper control blade pattern sei etion. The ramping starts at the point in the cycle when all the ramp cell blades .re about 40% withdrawn and all other control blades are fully withdrawn (EOC'). This corresponds to about 12 to 21 full power days before the end of full power capability.

The power ramp in the special demonstration bundles is achieved by withdrawing the ramp cell control blades in 1.5-ft increments. The reactor power is allowed to coast down between 1% and 5% prior to pulling the blades so that the core power will stay at or below 100% of rated power following the ramp. Each ramp cell blade is pulled 1.5 ft, in turn, prior to any further withdrawal of a ramp cell blade. The procedure (coastdown followed by blade withdrawal) is repeated over the last 15 to 20 full power days until the ramp cell blades are fully withdrawn.

2-2

~.

i l

NEDD-24259-A 1 A typical power distribution in a special demonstration bundle during ramping is

,i shown in Figure 2-9. Figure 2-9a shows the linear heat generation rate (LHGR) in kW/ft for the average fuel rod before and after a 1.5-ft control blade i withdrawal. Figure 2-9b shows the peak power rod response. The peak power rod j will be the fuel rod in the corner of the bundle adjacent to the control blade

-(W-W corner rod).

i i

l Table 2-1 I

PLANNED DEMONSTRATION FUEL LOADING STRATEGY Nominal Number of Bundles Bundle Average Loaded (All Fuel Enrichment Gadolinia Loaded in Cycle 6) (wt% U-235) Content comments

.t s

16 2.65 6 rods @ 2% Ramped in Cycle 6 16 2.65 6 rods @ 3% Ramped in Cycle 7 special demonstration 16 2.97- 7 rods @ 4% Ramped in Cycle 8 bundles 16 2.91 7 rods @ 4% Ramped in Cycle 9 68 2.83 6 rods @ 3% Not ramped - standard demonstra-1- tion bundle 132 1

1

! T T

2-3

l l

NEDO-24259-A I

I .

l 6 5 4 4 4 4 4 5 5 4 2 Gd 2 2 2 4 4 2 2 2 1 1 Gd 2 4 Gd 2 2 HO 2 1 1 2 4 2 1 HO 2 1 1 Gd 2 4 2 1 1 1 1 1 2 4 2 Gd 1 Gd 1 2 3 5 4 2 2 2 2 3 4 ROD TYPE N o. wt % (U.235) wt % (Gd23 O) 1 14 3.80 -

2 21 3.00 -

3 2 2.40 -

4 14 2.00 -

5 4 1.70 -

6 1 1.70 -

Gd 6 3.00 3.00 l l

Figure 2-1. Cross Section of Fuel Bundle of 2.65% Average Enrichment 2-4 1

1

NEDO-24259-A 6 5 4 4 4 4 4 5 5 4 2 Gd 2 2 2 4 4 2 2 2 1 1 Gd 2 4 Gd 2 2 HO 2 1 1 2 4 2 1 HO 2 1 1 Gd 2 4 2 1 1 1 1 1 2 4 2 Gd 1 Gd 1 2 3 5 4 2 2 2 2 3 4 ROD TYPE No. wt % (U 235) at % (Gd203) 1 14 3.80 -

2 21 3.00 -

3 2 2.40 -

4 14 2.00 -

5 4 1.70 -

6 1 1.70 -

Gd 6 3.00 2.00 Figure 2-2. Cross Section of Fuel Bundle of 2.65% Average Enrichment 2-5

}

NEDO-24259-A

)

6 7 5 4 4 4 5 6 7 Gd1 4 3 Gd2 2 3 5 5 4 2 1 1 1 Gd2 4 4

4 3 1 1 HO 2 1 1 2 l l

l 4 Gd2 1 HO2 1 1 1 2 4 2 1 1 1 1 Gd2 3 5 3 Gd2 1 1 Gd2 1 4 6 5 4 2 2 3 4 5 l

ROD TYPE N o. wt % (U-235) wt % (Gd23 O) 1 18 3.95 -

l 2 7 3.80 -

)

3 6 3.30 -

1 4 12 2.80 -

I 5 7 2.40 -

6 3 2.00 -

7 2 1.70 -

4.00 Gdi 1 1.70 )

Gd2 6 3.00 4.00 Figure 2-3. Cross Section of Fuel Bundle of 2.97% Average Enrichment 2-6

l NEDO-24259-A BLADE GAP k

O

$ 7 6 5 5 4 4 4 5 5

m 6 4 4 3 2 Gd 2 4 5 4 Gd 1 1 1 Gd 2 5 3 1 1 H$ 1 1 2 4 2 1 Hg 1 1 1 2 4 Gd 1 1 1 Gd 1 2 4 2 Gd 1 1 1 1 3 5 4 2 2 2 2 3 4 ROD TYPE N o. wt % (U-235) wt % (Gd203) 1 19 3.80 2 12 3.30 3 4 3.00 4 12 2.40 5 6 2.00 6 2 1.70 7 1 1.30 Gd 6 3.00 3.00 Figure 2-4. Cross Section of Fuel Bundle of 2.83% Average Enrichment 2-7

e NEDO-24259-A

!?2~ 08+o8+o888888o o x8+8m8+8m m84 mo o 8+s48+88+884848+88+884840 8+8 M d if 8 8 8+8 8+8 8+8 84 M M E 8f om8+88+88+88+88+88+88+88+88+8848+8840 8+88484848f8+88f8f8+88+88+88+88+88+88+8

+8848+88+88+88+88f8+88+88+88f848f8+88+8 8+88+88f888fM848+88+8848+8848f8f8+8 8+8848+884M8+88f84848f8f848+88f8+8 1848+88+8"+8848+88+88+88484848+88+88+8 848+888848+88f8+88+88fM8+8848f 84 M M E 8+8 8f 8f 8f 8+8 M H E M 8+88+8848f848+88+88+88+88484 84&BM8f8+88+88+8848 8+884848+88+8 Figure 2-5. Ramp Cell Locations, Cycles 6 and 7 2-8

NEDO-24259-A

. l'"1- o8888888888o

%+8888888888888880 084 8+s H E E Po8f M H if 84 o 88888888888888888+888888888 oBEHi88888BBBBBBB8888:HE8o 888888888888888888888888888888 888888888888888888888888888888 888888888888888888888888888888 888888+88888888888888888888888 8

EM84eMe8fM848f8fM8fFo8f BEHi88BB8888888888BBENE8 88888888888888888888888888 8888HE888888888HB888 888888888888888888 888B888888 Fly,ure 2-6. Ramp Cell Locations Cycles 8 and 9. Driver Fuel Indicated by D 2-9

NEDO-24259-A oBaeaeafaa80 osavaB88888BB88eaa+ o N

o848f8f84BfE8fBfBf8fB4 B!E88888888888888888888!8 oBIBBB888BBBBBBBBB8888888!8o bub 888888880888888888888888828 B:B8888888888888888888888888!8 B:B8888888888888888888888888!8 B:888888888888888888B8888888!8 Bf848f848fE8f848f848f88f8fEf B!B88888888888 888888888!8 B!B888888888888888888888!8 o8888BBBBBBBB88888888BB MMB888BBBBBBEE!e 888eE8M!8

~

l E PROPOSED BUNDLE LOCATIONS Figure 2-7. Proposed Pre-Ramp Locations for Special Barrier Bundles 2-10

i NED0-24259-A l

l NORMAL OPER ATION R AMPING C b

! - 370 fpd -

12-21 fod +

l l BOC = BEGINNING OF CYCLE 7 100 -

EOC = END OF CYCLE z fod = FULL POWER DAYS o

C EXPECTED RANGE OF E BLADE INSERTION N 75 -

l l5 ///// /

50 -

25 -

, I I BOC EOC* EOC l

l l

l l

l l

Figure 2-8. Operational Strategy 2-11

zm8AOw?>

4 1

2: a L

A L I 2 WA AW 1

l l

R A u D R P H D I o T H t e

^ I T d WI a E W l

- D E D ) ) B O A D I 8 f t

b R L A / (

r B L W o K B k A

E P \ -

- E R R O E F T E F B A I

6

(

R G

H L

f l

d e

n u

B

- I 4

Y l

( I ll p

I 2

l C

e p

m a

- - - - - 0 R 2 0 1

8 s 4 2 o a 1

n i

n o

i _

t _

u b

i r

t s) i t 4

1 Df I l r5 EE ~ C e .

w1 I 2 o(

1 P s

l e ah i c I 0 xt 1

Ao N

D l O )

ax R I 8 ft ci E

G A

\ /

/

Wk )

iS p

yf

/

(

a T o R R (

E V

I 6 G A H .

L 9

/(ll '

I l 4 2

e r

u g

i 2

F I

- - - - - O 2 o 8 6 4 2 o 1 t

?5 G2 as:

7C -

NEDO-24259-A

3. FUEL !!ECHANICAL DESIGN The fuel and design of the barrier demonstration fuel is identical to the prepressurized 8x8 D-lattice retrofit fuel (P8x8R) described in Reference 9 except for the 0.003-in., high-purity zirconium liner metal-lurgically bonded to the inside sur' ace of the Zircaloy-2 cladding. The overall tube wall thickness is identical to the P8x8R tube wall thickness.

The fuel loadings as described in Figures 2-1 through 2-4, although differ-ent fron any described in Reference 9, have been selected because of demonstration program ramp requirements, not for any requirements of barrier fuel mechanical design.

The zirconium liner fuel meets the same thermal-mechanical requirements as those applied to the generic P8x8R design.

Other material property values and calculational methods different fron those described in Reference 9 are listed below:

(1) For all mechanical design analyses performed, the structural strength of the liner is ignored as soon as the material is irradiated. For the structural strength analyses in the unirradiated condition (beginning-of-life), the zirconium liner yield strength is set at 3250 psi (0.2% offset) at 700*F.

(2) Of the two analyses performed for each time point and condition analyzed and described in Section 2.5.3.1.2 of Reference 9, one is slightly modified. In the generic design evaluations, the first analysis assumes a differential pressure resulting from the maxinum coolant pressure and a zero psia internal gas pressure. For this analysis in the barrier fuel demonstration design evaluation, the internal gas pressure is set to a nini-mum fillgas pressure applied throughout the design lifetime of the analyzed rod.

(3) The stress concentration factor (K g) used in the fatigue evalua-tion of the zirconiun liner rod design is based on the cladding 3-1

NEDO-24259-A maxinum overall wall thickness (Kg = 2.20). The stress evaluation, however, is based on a minimun wall thickness equal to the minimun thickness of the Zircaloy-2 part of the cladding.

The global mechanical and thermal cycling stresses are cal-culated throughout the design lifetime of the fuel rod, and the fatigue evaluation is performed with the maximum alternating stress level applied to all cycles.

The calculated cumulative fatigue damage for the zirconium liner fuel rods is less than the allowable fatigue damage.

(4) For flow-induced vibration, calculated as described in Section 2.5.3.1.6 of Reference 9, the predicted vibrational amplitude of the zirconiun liner fuel rods, with the liner structural strength ignored, neets the design requiremente.

1 3-2

i NEDO-24259-A

4. SAFETY ANALYSES The generic methods and models for reload fuel safety analyses, as described in Reference 9, were reviewed for their applicability to the calculations required for the zirconium-lined barrier fuel demonstration bundles. All methods and models were found applicable to the barrier fuel demonstration bundles. When the final fuel-loading pattern is established, the calculations will be performed and reported for licensing in the same manner as for licensing an ordinary reload core. The fuel-operating parameters are within the bounds of the applicability of GETAE. There-fore, the bounding statistical analysis used to establish the MCPR safety limit is applicable to the PCI-resistant fuel.

Calculational methods for the following parameters and accidents were reviewed:

(1) MCPR operating limit; (2) vessel pressure ASME code compliance; (3) stability; (4) loss-of-coolant accident; (5) fuel loading error (mislocated or. rotated bundle); and (6) rod drop accident.

The largest uncontrolled k , calculated for the irradiated nonstandard fuel bundles in the barrier fuel demonstration bundles was within the range of values for standard fuel bundles. Since k,is less than 1.30, the nonstandard fuel bundles meet the criteria for storage in either Type A or Type B rack spacing or for high density storage racks designed by the General Electric Company.

4-1/4-2

NEDO-24259-A

5. REFERENCES

1. H. E. Williamson and D. C. Ditmore, " Current State of Knowledge High Performance BWR Zircaloy-Clad UO2 Fuel", NED0-10173, May 1970.

2. H. E. Williamson and D. C. Ditmore, " Experience with BWR Fuel Through September 1971", NEDO-10505, May 1972.

3. R. B. Elkins, " Experience with BWR Fuel Through September 1974",

NEDE-20922 (Proprietary) and NEDO-20922, June 1975.

4. R. B. Elkins, " Experience with BWR Fuel Through December 1976",

NED0-21660-P (Proprietary) and NEDO-21660, July 1977.

5. " Demonstration of Fuel Resistant to Pellet-Cladding Interaction; Second Semi-Annual Report, January - June 1978", General Electric Co.,

September 1978 (CEAP-23773-1).

6. " Demonstration of Fuel Resistant to Pellet-Cladding Interaction; Phase I Final Report", General Electric Co., March 1979 (GEAP-23773-2).

7. " Demonstration of Fuel Resistant to Pellet-Cladding Interaction",

Presentation by GE personnel to the U.S. Nuclear Regulatory Commission Staff,-March 25, 1980, USNRC, Bethesda, Maryland.'

8. R. K. Haling, " Operating Strategy For Maintaining an Optimum Power Distribution Throughout Life", TID-7672 ANS Topical Meeting, San Francisco, CA, September 26-27, 1963.

9. " Generic Reload Fuel Application", General Electric Co., NEDE-24011-P-A-1 (General Electric Co. Proprietary) and NEDO-240ll-A-1 (non-Proprietary)

July, 1979.

5-1/5-2

NEBO-24259-A APPENDIX A RESPONSES TO NRC REQUESTS FOR ADDITIONAL INFORMATION (Appendix A consists of Attachment A and its Attachments Al through A5 to a letter dated September 11, 1980.)

A-1

l NEDO-24259-A '

GENERAL h ELECTRIC NUCLEAR POWER SYSTEMS DIVISIO N GENERAL ELECTRIC COMPANY,175 CURTNER AVE., SAN JOSE, CALIFORNIA 9512s MC 682, (408) 925-3344 MFN-156-80 REE-054-80 September 11, 1980 U.S. Nuclear Regulatory Commission Division of Licensing Washington, D.C. 20555 Attention: Robert L. Tedesco Assistant Director for Licensing Gentlemen:

SUBJECT:

ADDITIONAL INFORMATION ON NEDO-24259, " GENERIC INFORMATION FOR BARSIER FUEL DEMONSTRATION BUNDLE LICENSING" The additional information requested in your letter dated h gust 28, 1980 is provided for your review and approval in Attachment A and in its Attachments Al thru AS.

Since you expressed a desire to have the background information as a part of the generic licensing document, the responses and attachments will be incorporated in the final document as appendices after approval .\

has been received.

We are concerned that the target date of September 15, 1980 for approval cannot be met. We believe that your approval by September 30, 1980 is necessary so that hardware manufacture can begin in October 1980 for the ti:nely implementation of this project.

We've noticed that most of the additional information requested deals with the nature of the pryram and its future plans. Very few of the requests dealt with safety issues. We are pleased with your apparent interest in the program, and ve believe that there are no outstanding safety problems. For this reason, we feel that from a licensing stand-point, there should be no reason that the required approval date could not be met. We will be pleased to keep you fully informed of the future I I

progress of the project.

)

A-2  ;

NEDO-24259-A GENERAL D ELECTRIC U,5. Nuclear Regulatory Commission Page 2 September 11, 1980 This project is considered to be of major importance to the General Electric Company and to the nuclear indcatry. We hope that you will make every effort possible to expedite the review and meet our necessary

j" schedule.

Very truly yours, R. E. Engel, Manager Reload Fuel Licensing REE:1m/1467,1480 Attachment cc: M. Tokar, NRC R. O. Meyer, NRC R. B. Bevan Jr. , NRC L, S. Rubenstein, NRC l

t 5

A-3

Mttdtnilitm t, a NEDO-24259-A l

l RESPONSE TO kEQUESTS BY NRC ON NED0-24259 REQUEST 231.1 Although the report is intended to provide a basis for the demonstration irradiation of PCI-resistant fuel in a commercial power reactor, hardly any background discussion is provided on the barrier fuels test program.

Although references are cited in the text, it is desirable to have a brief summary discussion of the barrier fuel test program. The discussion should focus on (a) test results that have indicated that this particular barrier material and design is effective against PCI failure and (b) how the tests to date support the belief that the insertion of the demonstration bundle in Quad Cities Unit 2 will not result in reduced safety margin or increased fission product release. The response to this question should be incorporated into NED0-24259, perhaps as an appendix, following completion of this review, so that the report constitutes a " stand-alone" document (which references other documents containing greater detailed information on specific points).

RESPONSE TO 231.1 The requested background information is provided in the attached text (Attachment A1), which has been excerpted from the report GEAP-23773-2 (Reference 6 of NEDO-24259). This information is a summary of Phase 1 of the program, " Demonstration of Fuel Resistant to Pellet-Cladding Interaction". Notice that within the Phase 1 work fuel test data were obtained that indicated that barrier fuel of the Zr-liner type had PCI-resistance to power ramps up to 18 KW/ft at a burnup of >16 mwd /kg U. More recent data are available which show similar PCI resistance of l the barrier fuel to a burnup of >23 mwd /kg U. These data are from ramp tests in a test reactor and are shown in Attachment A2. The portion of )

the figure on A2-2 within the dotted region shows the power /burnup range l in which failures were observed in reference fuel (conventional Zircair cladding). The Zr-liner fuel successfully withstood a ramp beyond the upper curve which marks the range in which 100% of the reference fuel A-4

NEDO-26259-A rods have failed. The superior performance of the barrier fuel under severe PCI conditions is evident.

However, in Document NE00-24259, licensing is sought for use of the specific barrier fuel bundles on a generic basis under normal operating conditions. Implicit is the inference that this barrier fuel will not result in reduced safety or in increased fission product release. The thermal-mechanical design work and the safety analyses for these bundles have shown all safety parameters to be within acceptable levels for a plant of the BWR/3 type.

In this program, tests have been performed for the effects of both the reactivity insertion accident (RIA) and the loss of coolant ac,:ident (LOCA), and results have indicated that Zr-liner barrier fuel behaves as well as conventional (non-barrier) fuel under these postulated accident situations. The results of the RIA tests appear here as Attachment A3 which is excerpted from the Phase 2 first semiannual report, GEAP-25163-1.

The RIA tests conducted at the Nuclear Safety Research Reactor in Japan have been fully documented in the report by J. Hoshi, K. Iwata, J. Yoshimura, and M. Ishikawa, " Fuel Failure Behavior of PCI-Remedy Fuels Under the Reactivity Initiated Accident Conditions", JAERI-K 8836 (May 1980).

Results of simulated LOCA tests of Zr-liner cladding appeared in the Phase 2 second semiannual report, GEAP-25163-2, which is hereby included as Attachment A4. See Section 3.3 for the LOCA data.

Release of fission products from barrier fuel rods which somehow become perforated has been addressed both in laboratory tests and in reactor tests of perforated fuel rods. No increased release of activity for the barrier fuel was observed or inferred from these tests. See Attachment A4, Sections 3.2.1 and 3.4.2.

Testing to date through the entire scope of the program has indicated the+ Zr-liner barrier fuel behaves at least as well as conventional fuel under all normal operating conditions. Further proof of this point is expected to be available in the Fall of 1980, when the two lead test assemblies of Zr-liner fuel will be examined after exposure to s12 mwd /kg U A-5

l NEDO-2 42'i9-A in Quad Cities Unit 1 (substantially higher exposure than estimated earlier in the program). Those results will be made available to NRC in the normal reporting format for this program; see response to 231.4. ,

REQUEST 231.2 The barrier fuel demonstration in Quad Cities Unit 2 is intenaed to demonstrate the comparative resistance of the design to PCI failure, not only through normal reactor operation, but also when subjected to planned power ramps near the end of four fuel cycles. This is a large-scale demonstration (involving 132 bundles of which 64 will be ramped) and the ramp feature of the demonstration, in particular, is unique. Because the fuel design (Zr-liner cladding) is novel; because the demonstration involves a large number of bundles; because repeated power ramp testing of a new fuel design has not been carried out heretofore in a commercial power reactor (i.e., this sets a precedent); because some rods may fail (particularly during the ramps); and because it is desirable to obtain potentially useful information on the performance of the barrier fuel subjected to the demonstration (in preparation for possible future reload applications), there is a special need for adequate failure detection, fuel damage surveillance and analytical failure prediction capability. Please address, therefore, the following concerns:

a. On-Line Failure Detection, Describe the on-line failure detection capability at Quad Cities Unit 2. Discuss the utility's commitment to use the instrumentation; e.g., if gas samples are to be obtained at the steam jet air ejector, how often would such samples be taken? Provide any correlations that might be used to relate activity monitor readings or coolant radiochemistry to the number and/or location of leaking fuel rods.

What is the minimum " delay time" (the time interval between the instant of cladding failure and the time at ' ich the failure can be detected)? Discuss the potential benefi u and costs of installing an on-line gamma spectrometer (GELI detector).

A-6

NEDO-24259-A

b. Post-Irradiation Surveillance The report should contain a discussion of the PIE program to be undertaken on the discharged demonstration bundles as well as any interim examination to be performed on tnat fuel during refueling outages. The disposition of failed fuel should be addressed as well as any examination that might be directed toward detecting

" partially damaged" fuel (i.e. , incipient failures).

c. PCI Failure Prediction Provide pre-ramp predictions of PCI failure probability using whatever model or code GE is currently using for that purpose.

Briefly describe the analytical method.

RESPONSE TO 231.2 This request refers to various aspects of the program work scope, but seems to express concern over fuel failures. Even with the power ramps at the ends of the cycles, all operation is planned to be within established limits and within the Technical Specifications. All test information indicates that fuel failure will not occur. Any additional restrictions on operation are unwarranted.

a. On-Line Failure Detection Within the scope of this generic license request the utility has no commitment beyond normal operation and the normal failure detection instrumentation and procedures. Pending NRC review and approval of the generic license document, NED0-24259, which will permit the utility to accept the barrier fuel bundles and to insert them in the core, a detailed operating plan for the demonstration will be developed jointly oy GE and the utility. That plan will address the question of increased sampling before and after the ramp. The correlations of bundle failure with offgas and water analyses will be considered at that time.

A-7

NEDO-24259-A It should be noted, however, that all operations will be within the plant's Technical Specifications, and the sampling methods and parameters described there are considered adequate, particularly i since, with the barrier fuel, the probability of failures is decreased.

b. Post-Irradiation Surveillance The demonstration program has been structured only through PHASE 2, which includes the first two power ramps in Quad Cities Unit 2 (through Cycle 7). Within the present scope of work the barrier fuel bundles will be sipped and visually examined at the discretion of the utility. The question of post-irradiation examination of discharged demonstration bundles has been deferred to PHASE 3, and the scope of work of this phase has yet to be determined.

c. PCI Failure Prediction With the current state of the art, General Elu tric does not believe a reliable analytical model exists to accurately predict PCI fuel failure probabilities. The ramp test data (Attachment A2-2) indicate no failures in the Zr-liner barrier fuel in severe power ramp tests. Since the power ramps in the demonstration will not be nearly as severe, no failures of the Ir-liner barrier fuel are expected. With regard to the conventional fuel in the core, the demonstration will keep power levels within current BWR practice and the experience base clearly indicates a high probability that the demonstration will produce no fuel failures. Reliance on experience and experimental data is consistent with the General Electric philosophy of test-before-use and is deemed to be the best engineering practice.

REQUEST 231.3 Section 4 " Safety Analysis" of the report provides little specific information on the potential effects of change in cladding properties on A-8

NED0-24259-A the results of the safety analysis. While it may be necessary to wait for the establishment of a final fuel loading pattern before licensing calculations can be performed and reported, general trends can surely be determined now.

Therefore, for each of the 6 parameters and accidents listed on page 4-1 of the report, please list the associated major cladding property parameter change that will have the greatest effect on the analysis of the accident and discuss in general terms what that effect will consist of.

RESPONSE TO 231.3 Refer to NE00-24259, p. 4-1/4-2. For items 1 through 3 and item 5, the cladding properties of interest are those involving the flow of heat from the fuel to the coolant. The flow of heat is influenced principally by the gap conductance and only secondarily by the thermal conductivity of the cladding. The barrier cladding is manufactured to the same specification for surface finish (i.e. roughness) as is conventional Zircaloy cladding, and no effect is anticipated regarding gap conductance.

The thermal conductivity of zirconium so closely matches that of Zircaloy that no effect is anticipated. The flow of heat is assured by the metallurgical bond between the zirconium liner and the Zircaloy. No evidence of de-bonding has ever been observed, even after severe deformation tests (strain $10%) of high exposure cladding samples. In manufacture the tubing is inspected for delamination over 100% of its length to assure soundness of bond and unimpeded flow of heat.

' Item 4 refers to the loss of coolant accident (LOCA) situation, which focuses on the peak cladding temperature (PCT). This, too, is affected by the flow of heat radially through the cladding, and the response for Items 1-3 and 5 applies here as well. In addition, the strength of the cladding must be considered. Previous calculations were performed for the two Zr-liner lead test assemblies and were shown in the report,

" Quad Cities Nuclear Power Station Unit 1 Reload 4 Supplemental Licensing Information for Barrier Lead Test Assemblies," NED0-24147 (September 1978).

In that analysis it was conservatively assumed that cladding strength A-9

NED0-24259-A l

was reduced 10% (i.e., the liner contributes zero strength). There was no effect on the calculational methods, however, the lower strength leads to an increase in the calculated number of perforations at a given PCT. Even with that unrealistically conservative assumption, the effect i upon LOCA performance was deemed acceptable. In Attachment A4, pp. 3-18 through 3-24*are the results of simulated LOCA tests, which show that the behavior of Ir-liner cladding (unitradiated) is similar to that of conventional Zircaloy cladding.

Item 6 refers to the rod drop accident. Testing at the Nuclear Safety Research Reactor in Japan has demonstrated that the presence of Zr-liner barrier cladding has no effect under such conditions (Attachment A3 and the previously referenced report JAERI-M 8846).

REQUEST 231.4 The report contains no description of key milestones or schediales.

Although some of that information was presented at the March 25, 1980 meeting between GE, DOE, Commonwealth Edison, and NRC staff, it would also be desirable to have that information in writing (to be incorporated into the report) along with a discussion of the intended plan for timely reporting of pertinent information to NRC regarding the results of the '

demonstration.

I RESPONSE TO 231.4 1

Milestones and target dates are shown in Attachment A5. All data generated in this program are reported informally and in a preliminary manner each month, with formal progress reports at semiannual intervals. Several members of the NRC staff now receive the semiannual report.

Results of the demonstration will be reported within the normal program report format. Requests for additional information should be made through the utility, and the question of data transfer to NRC will be considered at the next meeting of the Program Steering Committee, which guides the program within the bounds set by the program contract.

• pages A4-48 through A4-54 of this report A-10

NEDO-24259-A Attachment A1 (from GEAP-23773-2)

1. INTRODUCTION Experience in the nuclear industry with fuel rods of Zircaloy-clad urania has brought to light several causes of fuel rod f ailure. Most of these causes have been corrected by innovative design modifications and by improvements in manuf acturing processes. However, there persists one class of fuel f ailures which has yet to be eliminated and which presently is controlled by reactor design and operational constraints. These failures are caused by the direct interaction between the irradiated urania fuel, including its inventory of fission products, and the Zircaloy fuel sheath, or cladding. This phenomenon is called " fuel / cladding interaction" or " pellet cladding interaction" (PCI). The incidence of such f ailuresis closely linked to the power history of the f uel rod and to the severity and duration of power changes. Pellet-cladding interaction fuel f ailures have occurred in all types of water cooled reactors that are fueled with urania which is sheathed in Zircaloy: boiling water reactors (BWR), pressurized water reactors (PWR), Canadian deuterium-moderated reactors (CANDU), and the steam generating heavy water reactor (SGHWR).

Recently, national policy regarding light water reactor (LWR) technology has focused on the goal of improved uranium utilization in a fuel cycle that does not depend upon f uel reprocessing. Higher burnup can improve uranium utilization, but the design of fuel for high bumup service requires an acceptable resistance to PCI at those high burnup levels.

Of more immediate concern for utilities are the operational constraints which have been imposed on commer-cial power reactors to ameliorate the PCI phenomenon. While these operational procedures have been successfulin reducing the incidence of fuel failure,the procedures constrain certain reactor operations and are costly in terms of capacity factor. There is a strong incentive to provide a remedy,i.e., a fuel which is resistant to the PCI failure mechanism and which can be operated to high burnup with improved plant capacity f actors.

Building upon the General Electric Company's extensive previous efforts (1969 - 1977) to understand the PCI phenomenon and to develop potential remedies, this program was designed to exploit two remedies which General Electric (GE) had already identified as having good potential for success: (a) Cu barrier fuel and (b) Zr liner fuel.

Copper-barrier fuel has a Zircaloy sheath with a very thin layer of copper plated on the inner surface. Zirconium-liner fuel has a Zircaloy fuel cladding with a metallurgically bonded layer of zirconium on the inner surface. Both the Cu-barner fuel and the Zr liner fuel are known collectively as "barner fuel" The ultimate objective of this program is to realize demonstration of the PCI-resistance of a fuel based on one o}

these potential PCI remedies.The demonstration will be in a commercial BWR and it is intended to test a sufficient quantity of fuel to form a reliable data base regarding the performance characteristics of the new fuel. While it is not yet known in which reactor the actual demonstration will occur,it probably will be in a reactor of the BWR/3 type with a steady-state core, where the barrier fuel will be introduced as part of a reload batch.

Prior to the actual demonstration there must be an adequate data base to enable design and licensing; fabrication and quality assurance problems must be addressed; and there must be extensive nuclear physics, fuel management, and power history analyses so that the experimental fuel is properly tested with minimum risk to other fuel in the core. Consequently, the program has been structured to consider each of these aspects.

This program leads ultimately to the large-scale demonstration of one of the two remedy concepts discussed here: Cu-barrier or Zr liner. The overall program has been divided into three phases:

PHASE 1. Design and Supporting Tests PHASE 2. Large-Scale Demonstration PHASE 3. Demonstration Extending to High Bumup PHASE 1 now has been completed and includes all work from July 1,1977, through February 28,1979. PH ASE 1 included:

Al-1

NED0-24259-A (from CEAP-23773-2)

1. A generic nuclear engineering study to show that the demonstration is feasible in a reactor of the BWR/3 type.

l I

2. Laboratory and reactor tests to verify the PCI resistance of the Cu-barrier and the Zr-liner fuel types. l

3. Laboratory tests simulating loss-of-coolant accident (LOCA) conditions.

4. Design, licensing documentation, fabrication and pre-irradiation characterization of four lead test tssemblies (LTAs) for irradiation in the Quad Cities Nuclear Power Station Unit 1, beginning in Cycle 5.

PHASE 2 will continue the work of PHASE 1, and it will also include:

1. Selection of the remedy fuel for the demonstration.

2. Nuclear design and core management of the demonstration, expanding from the generic feasibility study in PHASE 1 to a specific reactor and target cycle, including bundle nuclear designs.

3. Design, licensing documentation, and manufacturing of the demonstration fuel.

4. The demonstration per se;i.e., the irradiation (including specially designed power rampe to test PCI resistance) and the evaluations. As presently perceived, PHASE 2 will include the irradiation through September 30,1984.

5. Continued irradiation and evaluation of the four LTNs.

PHASE 3 is intended to extend the demonstration to high burnup. It is contingent on successful completion of PHASES 1 and 2, and details of the scope have yet to be defined.

This report is the Final Report for PHASE 1 of this program. lt covers progress since the last progress report,'

as well as c summary of the entire PHASE 1 effort (Section 2).

l Al-2

NED0-24259-A (from GEAP-23773-2)

2.

SUMMARY

FOR PHASE 1 2.1 DESIGN OF LARGE-SCALE DEMONSTRATION Using Unit 1 of the Quad Cities Nuclear Power Station at the beginning of Cycle 6 as an example,the feassbility of the demonstration irradiation was determined. Quad Cities 1 is an operating commercial power reactor of the BWR'3 type with a steady-state core. The power density and other design features of a BWR'3 make such a reactor well-suited for the demonstration, but the results of the demonstration should be applicable generally to LWR's.

The demonstration, as presently perceived, willinvolve the insertion of the advanced. PCI-resistant f uel as part of a normal reload batch. The demonstration has been so designed that (a) the PCI resistance of the advanced fuel can be demonstrated by suitable power increases on certain nodes (i.e., axiallocations) of the advanced fuel bundles;(b) simultaneously, the power limits and power changes on the conventional, non-remedy fuel are held within limits specified to minimize the risk to the conventional fuel; (c) the demonstration does not inhibit unduly the reactor performances as a central station power plant; and (d) the operational procedures are compatible with the needs and capabilities of the utihty which operates the plant. The demonstration plan which has been developed fulfills these goals.

The demonstration nuclear core design involves the use of test cells which contain the barrier fuel assemblies and which are symmetrically placed in the core. Each test cell contains four barrier f uel assemblies surrounding one cruciform contru blade. The test cells are operated with their control blades inserted 60 to 100% of their length during most of the reactor cycle. Near the end of the cycle the control blades of the test cells are withdrawn in a stepwise f ashion to impart a rapid increase in power in the barrier fuel to test its resistance to PCI. The test cells are surrounded by a buffer of high exposure (~20 mwd /kg-U) fuel bundles.This buffer zone serves to isolate the increase in power due to the withdrawal of the test cell control blades and thereby to protect the standard fuelin the core.The entire process has been analyzed to compare the suggested operation using the demonstration fuel and the demonstration mode of operation to what would normally be expected for Cycles 6 through 13.The demonstration mode produces very nearly the same energy as the normal mode of operation, but the extra neutron absorption of the copper barrier (~0.25%

reactivity penalty) results in -0.14% energy penalty for the de nonstration. Use of Zr-liner fuel results in no energy penalty. Power ramp simulation analyses using a 3-dimensional coupled nuclear-thermal hydraulic sin:ulation have shown that the demonstration is feasible, providing both adequate design margin and a good demonstration of PCI resistance of the barrier fuel, while protecting the conventional fuel bundles in the core from power changes likely to produce fuel cladding penetrations by PCI. Also, margins for transient and accident situations were shown to be adequate in the demonstration mode.

2.2 SUPPORT TESTS FOR LARGE-SCALE DEMONSTRATION 2.2.1 Laboratory Tests 2.2.1.1 Expanding Mandrel Tests Expanding mandrel tests provide a controlled, localized, noncompliant stress system on cladding specimens along with exposure to temperature and corrosive environments that produce stress corrosion effects in Zircaloy.

Thus, the expanding mandrel tests constitute a laboratory simulation of PCI. Such tests were done with both irradiated and with unirradiated barrier cladding and with suitable control specimens. The expanding mandrel tests were used to compare the stress corrosion resistance of irradiated Cu-barrier, Zr-lined and conventional cladding.

Tests were done also with unirradiated materials to explore the effects of fabrication parameters. ,

Unirradiated specimens were tested in several environments:(a) flowing iodine (1,)in a carrier gas of argon. (b) pure cadmium (either above or below the melting temperature), anJ (c) liquid cesium saturated with cadmium (Cs/Cd). Cold-worked Zircatoy reference specimens were consistently embrittled in such tests.While some tests were done with unirradiated Cu-barrier tubing, the emphasis was on Zr-lined tubing, where the effects of liner thickness, purity (oxygen content), and grain size were explored. lt was found that in tne unirradiated condition the resistance of Al-3 1

l 1

i l

NEDO-24259-A  ;

(from GEAP-23773-2)

Zr lined Zircaloy tubing to simulated PClis insensitive to either the thickness or the punty of the liner. However,if the grain s!ze of the zirconium liner was allowed to grow to >35 pm, the resistance to PCI was degraded. In tests with unirradiated Cu-barrier Zircaloy tubing it was shown that the PCI-resistance of the Cu-twrrier tubing could be degraded if the Cu-barrier tubing is given an anneal sufficient to significantly interdiffuse the copper and the Zircatoy.

Irradiated specimens were obtained mainly from the unfueled plenum regions of test fuel rods (removable segments from segmented fuel rods) which had been irradiated in commercial BWR's and subsequently power ramp tested for PCI in a test reactor. Expanding mandrel tests were done at reactor temperatures (300 to i 15'C) in atmospheres containing either I, vapor or pure Cd.These tests at burnup levels up to ~10 MWdikg U (fluences up to 2.4 x 108' n/cm', E>1 MeV) showed that when the copper barrier had been diffusion-bonded, the Cu-barrier tubing lost much of its PCI resistance. Irradiated Zircaloy tubing having either an unbonded copper barrier or a zirconium liner showed good resistance to simulated PCI at these fluence levels.

2.2.1.2 Barrier Characterization and Stability Although the early experiments were done by General Electric on electroplated Cu barrier tubing, the Lead Test Assemblies (LTA's) (see Part 3) were prepared by an electroless copper plating method. The electroless technique was thought to have advantages both in ease of f abrication and in product uniformity. Much of the effort in this subtask was devoted to chemical and metallurgical characterization of the electroless copper barrier. The Zr-lined Zircaloy tubing was characterized with respect to crystallographic texture.

The electroless copper barrier was found to have very fine grain size (mean intercept distance <0.5 gm).

Chemical analyses by means of ion microprobe showed the major impurities of the electroless product to be hydrogen and carbon.The crystallographic texture of the zirconium liner and the Zircaloy tube in which it was bonded was not markedly different from that of standard Zircatoy tubing.

The Cu-barrier tubing received further attention with respect to its stability, especially its behavior in the presence of steam-hydrogen mixtures as might occur in a fuel rod with a e! adding penetration. It was found in f abre,atory experiments that the presence of the copper barrier promoted the absorption of hydrogen by the Zircaloy in an environment of steam and hydroger.. The use of copper plated on oxidized Zircatoy (a thin layer of zirconia separating the copper and the Zircatoy) tended to retard the absorption of hydrogen,but did not prevent it entirely.

2.2.1.3 Effects of Irradiation on Zirconium of Various Purities Irradiated specimens of zirconium (flat stock) of different purity levels were tested for resistance to stress corrosion cracking (or embrittlement) in environments of pure cadmium or liquid cesium saturated with cadmium (Cs/Cd). The intention was to determine the influence of purity on the resistance of irradiated zirconium to stress corrosion and thereby to PCI. With sheet specimens the strain rate can be directly controlled and varied by orders of magnitude. Results showed that both crystal bar zirconium and sponge zirconium retain a high degree of resistance to embrittlement in these environments at strain rates ~0.01 min ~', but at much higher strain rates (~0.1 min-') some embrittlement was seen.

2.2.2 Licensing Tests 2.2.2.1 Simulated Loss of-Coolant Accident (LOCA)

Laboratory experiments were done to compare the behavior of barrier fuel with that of reference fuel under simulated LOCA conditions. These experiments invoived the use of cladding with urania dummy fuel pellets; the cladding was subjected to a pressure / temperature transient expected in a postulated LOCA situation. In terms of overall cladding deformation and tendency for perforations to occur,the behavior of barrier cladding (both Cu-barrier and Zr-lined) was not markedly different from that of reference Zircatoy cladding. Under the extreme temperatures involved with a LOCA the copper barrier and the Zircalcy interacted in a eutectic reaction as had been expected.

Al-4

NEDO-24259-A (from GEAP-23773-2) 2.2.2.2 Reactivity initiated Accident Reactivity initiated Accident (RIA) comparisons between barrier fuel and reference fuel are to be done at the Nuclear Safety Research Reactor (NSRR) in Tokai, Japan. Barrier and reference cladding samples were supphed to Battelle Pacific Northwest Laboratory where special fuel pins were fabricated and shipped to Japan. Tests are scheduled to occur in 1979 and will be reported in PHASE 2.

2.2.3 Fuel Irradiation Tests This task addresses directly the question of PCI resistance. it involves the irradiation of expenmental fuel rods and subjects them to power ramp tests in a test reactor especially equipped for such tests. In PHASE 1 such tests were done at burr $up levels ranging to ~16 mwd!kg-U under power history and power ramp conditions that consistently produce cladding perforations by PCI in convention &l fuel (i.e., fuel with nonbarrier reference Zircafoy cladding) of equivalent burnup.

At burnup levels up to 10 mwd /kg-U both the Cu-barrier fuel and the Zr-hner fuel demonstrated supenor resistance to PCI. Not only did these barrier fuei rods remain sound after a ramp to high powers, but careful post-test nondestructive and destructive examinations revealed no incipient cracks of the barrier cladding. Tests at higher burnup showed that while all of the barrier configurations appeared to be superior to conventional fuel, cladding f ailures did ocr'

• in fuel with certain copper barrier configurations. Copper barrier fuel with 5 gm thick copper failed as did the diffusumbonded Cu-barrier fuel. Copper barrier cladding wsh 10 gm thick copper which had not been diffusion bonded durir:g fabrication continued to resist failure by PCI at a burnup of 12.5 mwd /kg-U (rod average). In tests thus far the Zr.hner fuel has resisted failure by PCI to burnups up to 16.6 mwd /kg-U (rod average) and linear powers as high as 59.1 kW/m (18 kW/ft).

Fuel ramp testing is scheduled to continue in PHASE 2 to support the large-scale demonstration in a commer-cial power reactor.

2.3 LEAD TEST ASSEMBLIES The actual demonstration of the Cu-barrier and the Zr-liner fuel concepts starts with the f abrication,lrradiation and evaluation of lead test assemblies (LTNs).The LTNs have f ull sized fuel rods in an 8x8 array and are intended to provide both fabrication experience and lead irradiation experience for the barrier fuels. Thus, the LTA's will start their irradiation before the large-scale demonstration fuel is inserted into a reactor, and the LTNs will lead the large-scale demonstration in burnup. No special power maneuvers are anticipated f or the LTNs;their function is to be irradiated under service conditions like that of conventional BWR fuel and to be evaluated for licensing purpcses with respect to dimensional stability and ability to perform at relatively high power ratings. In PHASE 1 the LTNs were designed and f abricated. trradiation was initiated in Cycle 5 of the Quad Cities-1 power reactor beginning in February, 1979. Their continued irradiation and evaluations are scheduled for PHASE 2 and PHASE 3.

Four LTNs have been fabricated, two with Cu-barrier fuel and two with Zr-finer fuel as follows:

-Copper barrier plated on etched Zircaloy

-Copper barrier plated on autoclave-oxidized Zircaloy

-Zirconium liner (crystal bar zirconium) coreduced with Zircatoy

-Zirconium liner (low oxygen sponge zirconium) coreduced with Zircatoy Each LTA contains 60 full-length fuel rods, two water rods, and two rods which are segmented. The segmented rods were included as a contingency; they each are composed of four short (~ I m long) fuel rod segments which can be readily disassembled for detailed examinations or for fuel power ramp tests in a test reactor should such tests be deemed desirable.

The LTNs were designed for inclusion in symmetric locations in the core of Quad Cities Unit 1, at the start of Cycle 5. Fabrication was completed and the LTNs were delivered to the Quad Cities Nuclear Power Station in December 1978 in time for the scheduled refueling outage (starting January 1979) pelor to the start of Cycle 5 (February 27,1979).

Al-5

NEDO-26259-A (from GEAP-23773-2)

During the fabrication of the LTNs they were thoroughly characterized to facilitate evaluations at subsequent refueling outages of the Quad Cities 1 power plant. Also, preliminary work was done at the Quad Cities Nuclear Power Station to assure the availability of a thorough and complete power history record to aid in the performance  !

evaluations of the LTA's.

I Al-6

l~ 'N

\

RAMP TEST RESULTS - REFERENCES 80 - 24

~

70 -

20 -

60 - 18 -

9 E E -

9 * - Z j 50 - } 16 , f h i TT y T 7 g 5 E I4 4 4h N h h

> y 40 - $ 12 -

h kh4 '$ $

[ k 2 10 -

M 30 - M

$ $8 -

20 - 6 - O CC FAILED O CC SOUND A SRP-FAILED (f FAILED BELOW 4 _

10 - A SRP-SOUND INDICATED POWER) 3 2 -

0 0

I I I I ' I I '

0-O 2 4 6 8 10 12 14 16 18 20 22 8 BURNUP (mwd /kg U) "

01807-1 $

b

RAMP TEST RESULTS - Zr LINER 80 - 24 22 -

s N OO 70 -

20 -

s%s 60 - 18 -

s sA an vTrk.4,,A AA A A

~~~' ' ' -------

E -

N

}g 50 - E 16 s g N s M m x 14 -  %

8

> w w  %*% 8 7 3 40 - 3 12 - 5 N o a.

o

o. '% 3 10 -  %-

• y 30 - y '~~ :I-m W 8 -

20 - 6 -

O CC-SOUND 10 - A SRPSOUND 2 -

~

iI i I i l i I i I i l i I i l i I i l i l i 0 2 4 6 8 10 12 14 16 18 20 22 24 BURNUP (mwd /kgU) 01807-3

NEDO-24259-A Attachrnent A3 (from GEAP-25163-1) i The coolant temperature below the EBR Il core and at tne entrance to the core is nominally 371 'C (700 *F).

Based on the subassembly power, coolant flow rate and heat transfer from surrounding subassemblies, the exit coolant temperature was calculated to be 462*C (864'F) for the test subassembly. A finear temperature rise from 371'C is assumed over the 34.3 cm core length. Ex-reactor control tests with thermal histories correspond-Ing to that of the in-reactor specimens are in progress. A second series (EBR-ll 2) of four nonfueled tube specimens of the following types - reference (bright etched) Zircaloy 2, copper on autoclave-oxidized Zircaloy 2,0.076 mm crystal bar zirconium-lined Zircaloy 2, and 0.076-mm low-oxygen sponge zirconium-lined Zircatoy 2 - is cur.ently under irradiation in Row 4 of EBR ll for Runs 100 through 103. The projected peak fluence (core midplane) for the rods at the conclusion of the EBR-II-2 Irradiation is ~8 x 102' n/cm8 (E > 1 MeV).

The projected fluence at the bottom of the core (lower coolant temperature) is ~4.5 x 102' n/cm8 (E > 1 MeV).

2.2 SUBTASK 11.2. LICENSING TESTS (T. C. Rowland and L. D. Noble)

The objective of this task is to obtain experimental data on the performance of fuel with a copper or zir-conium barrier as compared to that of standard fuel during Rf A.

For a boiling water reactor (BWR), the design basis RIA is a hypothetical case in which the control rod (blade) becomes decoupled from the control drive while in the inserted position. It is then postulated that the control drive is withdrawn, but the control rod remains in the reactor, to drop out, suddenly, at some later time.

Analysis indicates that the most severe transients occur during ambient or hot standby conditions. The barrier tubing will be tested under both of these conditions.

The tests at ambient temperature were conducted in 1978 and 1979 at the Nuclear Safety Research Reactor (NSRR) in Japan. These tests were arranged by the U.S. Nuclear Regulatory Commission (NRC) through their cooperative exchange agreement with the Japan Atomic Energy Research institute (JAERI) for the exchange of r

safety research information. Tests at elevated temperatures are scheduled for late 1979. Hot standby tests will be performed in 1980 and 1981 at the Power Burst Facility (PBF) in Idaho, with irradiated fuel.

Currently,31 tests with GE barrier tubing are planned for NSRR. Sixteen of the tests have been performed at room temperature and atmospheric pressure (0.1 MPa). Included were six reference pins with conventional tubing, and five pins, each of copper and zirconium barrier tubing. Thirteen tests will be performed at high temperature (286 *C) and pressure (7.2 MPa); eight with reference tubing, and five with either copper or zirconium barrier tubing. This test matrix may be modified as a result of test results.

The RIA tests deposit energy into the fuel very rapidly by pulsing the reactor (such as NSRR) with a large power burst of short duration. For NSRR, the power burst may typically have a half width of 4 to 5 ms, and the energy deposition may be as high as 500 callg (2092 J/g) of UO,, depending on the fuel enrichment. At very high energy depositions, the f uel bece mes fragmented, while at low magnitude depositions no visible change occurs.

At intermediate energies, external cladding oxidation, cladding deformation, and small cracks may develop.

The tests planned for NSRR include energy depositions up to approximately 350 cal /g (1464 J/g) as in-dicated in the test matrix of Table 2.21.These span the expected range of test conditions from cladding oxida-l l tion through complete f ragmentation. The energy depositions cited here include room temperature enthaf py and are averaged over the fuel column length.

The fuel pins (i.e. short fuel rods designed especially for testing in the NSRR) were manufactured at Battelle Northwest Laboratories. Tubing was provided by GE. The fuel and fabrication were provided by the NRC.

L 2.2.1 Nuclear Safety Research Reactor RIA Test Results The results of the RlA tests at NSRR will be published in a JAERI report by Hoshi,et al.' Here the results to date will be summarized briefly. The fuel pin characteristics are shown in Table 2.2-2, and the fuel pin is shown

schematically in Figure 2.2-1.(See photograph of NSRR fuel pin assembly in Reference 2, p. 5-40.) There were no flux depressors at the ends of the fuel column so there was a fairly large amount of end flux peaking, especially at the lower end of the fuel column (Figure 2.2-2). Essentially all of the failures occurred at the flux peak at the A3-1

NEDO-24259-A (from GEAP-25163-1) 1 Table 2.21 NUCLEAR SAFETY RESEARCH REACTOR TESTS Total Energy Deposition (callg-UOJ Number Number 150 215 to 240 250 350 Planned Completed Fuel TypelTest Condition 120 4 1 1 8 6 1 1 Reference / Ambient 5 5 Copper / Ambient 0 1 2 1 1 2 1 1 5 5 Zirconium / Ambient 0 1 4 1 1 8 0 Reference /High Temperature 1 1 and Pressure 2 1 1 5 0 Cop'per or ZirconiumIHigh 0 1 Temperature and Pressure 31 16 Table 2.2 2 CHARACTERISTICS OF NSRR RfA FUEL PINS Type of Cladding Tested

1. Reference type Zircaloy-2

2. Zrlined Zircatoy-2

3. Cu-barrier Zircaloy-2 Fuel Pellets 10% U 235 Enrichment Density 95% theoretical 45' chamfered edge Geometry Dimension 10.57 mm Pellet o.d.

Pellet length 10.7 mm Cladding o.d. 12.52 mm Cladding wall thickness 0.86 mm Gap width 0.115 mm

~10% of wall thickness Zr liner thickness

~0.01 mm Cu-barrier thickness l Fuel column length 135.15 mm l

l I

i i

1 A3-2

CENTER OF FUEL COLUMN CORE CENTER I

I .

g 135 mm  ;

SPRING + 33 +4 33 +

TOP END FITTING " I p gTTING IRON SLUG Q

/ TC 3 0 TC 20 TC,i n n oZ I o > O@

e. 9. d..M.. ..S.b5 3b'U6b'o . .

gm

,t; b

TC6 TC4 TC

• 1 5

w -i PELLET CLADDING STAINLESS STE EL DISK v

[ STAINLESS STEEL DISK SPRING HOLDER ZlRCALOY SPACER Figure 2.21. Nuclear Safety Research Reactor RfA Fuel Pin

NEDO-24259-A (from GEAP-25163-1) 2.5 2.0 -

1.5

FUEL STACK: 135.15 mm 5 i s l 2

G 5 '

E l In - -

1 I

I 0.5 -

I 1

I l

l l l l l l LOWER END UPPER END 1 I I t i l i I I I I I I I l l l l AXIAL POSITION (cm/div )

Figure 2.2-2. Typical Axial Power Distribution A3-4

NEDD-24259-A (from GEAP-25163-1) bottom of the fuel column which would indicate that the energy deposition to f ailure should be 10 to 20% higher than the nominal. However, previous tests performed in the NSRR where the flux peaking was eliminated showed that the failure threshold was the same with flux peaking as it was without, so no correction was war-ranted.

Reference fuel pin results are shown in Table 2.2-3, Zr. liner fuel results in Table 2.2-4, and Cu-barrier fuel results in Table 2.2 5. The results are compared in Figure 2.2-3 and the maximum surf ace temperatures are com-pared in Figure 2.2-4.

The fuel failure threshold energy for the reference pins and tne Cu-barrier fuel pins is 260 to 290 callg UO, (1088 to 1213 J/g). This is about the same as for NSRR standard fuel rods and the SPERT IV test results.' The Zr.

liner fuel rod failure threshold appears to be slightly higher, approximately 300 cal /g UO, (1255 J/g UO,). At higher energies, about 400 callg-UO,(1674 J/g), none of the fuel rods in the current tests fragmented while in previous NSRR tests and SPERT IV tests the cladding fragmented. The maximum cladding temperature of the Cu barrier fuel rods was somewhat higher than the other types of fuel.

In st.mmary, no significant differences were observed between the barrier fuel pins and the reference fuel pins in RIA conditions.

2.2.2 Planned PBF Tests Segmented fuel rods which were irradiated in BWR's were shipped to EG&G, Idaho,in March 1979 for RIA testing sponsored by the NRC. The objective of the RIA testing is to determine if the failure threshold changes with exposure.

The fuel rods (length = approximately 1m) which have been shipped to EG&G for testing in the period June 1980 through February 1981 are listed in Table 2.24.

2.3 SUBTASK 11.3. FUEL 1RRADIATION TESTS 2.3.1 Segmented Rod Irradiation Tests (J. H. Davies, E. Rosicky, E. L Esch, D. K. Dennison) 2.3.1.1 Bundle Status The irradiation status of the three segmented test rod assemblies is updated in Table 2.3-1. Four segments were removed from the SRP-3 (Millstone) bundle during the end of Cycle 6 refueling outage in May.

These segments are listed in Table 2.3-2.

2.3.2 Ramp Tests 2.3.2.1 Test Results - 1978 Ramp testing of twelve SRP segments in the R2 Reactor at Studsvik was described previously.' The preliminary results are reproduced in Table 2.3-3. These results were subsequently confirmed by visual examina-tion (Table 2.3-4) and neutron radiography (Table 2.3-5).

Final test results, providing greater detail and more refined estimates of failure powers, are summarized in Table 2.3-6. Note the set of data under the heading, power " spike". This ef fect was briefly mentioned in the previous report.* During ramp testing in R2, rod power is monitored calorimetrically by measuring inlet and outlet temepratures in the rig plus coolant flow rate. Fission product activity in the loop is continuously monitored and a defect is indicated by a large increase in activity. Relative rod power and loop activity are recorded in parallel on a single chart. In five of the nine recorded defects the defect signal was preceded by a small spike or deflection on the strip chart output of the instrument monitoring relative power as a function of time. The time interval between the spike and a large activity release ranged from about 1 minute up to 98 minutes. An example where there was good separation of the two signals, is shown in Figure 2.31. These spikes A3-5

NEDO-24259-A (from GEAP-25163-1) 500

$; FAILURE O: aourai'une l

400 -

G S e 250 -

~ce 8

e 6

e am - 9 9 m

2 g 9 9 a

! 250 -

O FAILURE THRESHOLD FOR NSRR STD FUEL PINS

2. -

O O O o 150 I I i 100 GE-REF Zr-LINED Cu-BAR RIE R Figure 2.2-3. Comparison of Failure Threshold for Reference and Barrier Clad Fuel Rods A3-6

NEDO-24259-A (from GEAP-25163-1)

<oo I

l 3500 -

O NSRR - STANDARD PIN

$ GE REFERENCE O Zi LINER O Cu BARRIER 3m0 -

25 .

G cl.

E a

y 20w -

e E

3 r .,

i5m - 6 o g

• O 8

I 1000 -

O l

l '

g

$w -

I I l l l 100 150 200 250 300 350 ENERGY DEPOSITION (cal /g UO I 2

Figure 2.24. Maximum Cladding Surface Temperature at Axial Midpoint (Data with arrows are lower-bound estimates)

A3-7

Table 2.2-3

SUMMARY

OF TEST RESULTS ON REFERENCE FUEL PINS (GE CLADDING)

Maximum Water Maximum Cladding Surface Temperature

• Maximum Capsule Column Energy No. 2 No. 3 No. 4 No. 5 No. 6 Pressure ' Velocity Deposition Test No.1 bar (MPa) (mis) Post. Test Observation (calig UO,) No. ('C) (*C) ('C) ('C) (*C) (*C) 700 380 540 600 450 - - Cladding surface was slightly 169 501-2 720 discolored in the fuel region.

N1s film boiling. m A

209 501-1 1120 1150 1120 1180 1120 1130 - - Cladding surface was 3$

discolored black over the aE

> entire fuel region. Fuel pin did 90 Y not fail,7-10s film boiling.  ?$

U$

257 501-3 1420 1410 1350 1400 1420 .1330 - - Cladding surface was 7s discolored over the entire fuel y region and oxidized Zircaloy O film flaked away. Fuel pin did not fall,8-13s film boiling.

284 501-4 1690 ;-1520 1530 1630 1520 1530 - - Melted claddinglor fuel was pushed out from the cladding and relatively large ballooning of cladding was observed in the tr'wer partion of the pin.

Several hoids were at the thermocouple locations.

305 501-7 1620 >1670 1600 1640 1640 1620 - -

Fuel rod fractured into two pieces during disassembly. A large void was observed in the fuel in the lower fractured por-tion.

Table 2.2-4

SUMMARY

OF TEST RESULTS ON Zr LINED FUEL PIN Maximum Water Energy Maximum Cladding Surface Temperature

• Maximum Capsule Column Deposition Test No.1 No. 2 No.3 No. 4 No. 5 No. 6 Pressure Velocity (cal /g UO,) No. ('C) ('C) ('C) ('C) ('C) (*C) bar (mPa) (mis) Post Test Observation 393 501-8 >1150 >1030 >1120 >1120 - - 2.5 2.2 Cladding was melted exten-

. sively at the lower portion of the rod. Fuel was expelled from the rod and fragmented.

Oxidation of the cladding was observed in a portion of the plenum.

171 502-2 640 700 480 710 810 800 - - Cladding surf ace was slightly $

discolored over the fuel gg region, N1s film boiling. g 208 502 1 1110 1130 1130 1110 1250 1140 - - Cladding surface was kwN p

y . discolored black over the entire fuel region. Fuel pin did U$

'c not fall,6 3s film boiling. Eh w

304 502 4 1510 1500 1480 1500 1410 1510 - - Cladding surface was b discolored and dulled over the entire fuel region. Fuel pin did not fall,7-11s film boiling.

313 502-3 1690 1530 1510 1650 1600 1650 - - Fuel pin fractured into two pieces during disassembling.

A void was observed in the fuel and the cladding was melted.

394 502-5 1130 1100 1480 1170 - -

3.4 (0.34) 4.8 Cladding was melted exten-sively. Fuel was expelled from the pin and fragmented.

Oxidation of cladding was observed in a portion of the fuel plenum.

Table 2.2-5

SUMMARY

OF TEST RESULTS ON Cu-BARRIER FUEL PINS Maximum Water Energy Maximum Cladding Surface Temperature Maximum Capsule Column Deposition Test No.1 No. 2 No. 3 No. 4 No.5 No. 6 Pressure Velocity (callg UO,) N o. (*C) ('C) ('C) (*C) ('C) (*C) bar (mPa) , (mis) Post-Test Observation 169 503-2 710 730 970 950 830 b30 - - Cladding surface was discolored over the entire fuel region,1-6s film boiling.

201 503 1 1370 1280 1200 failed 1350 1350 - -

Cladding surface was m discolored black over the Q entire fuel region. Fuel pin did $$

D 1640 failed not fall,12-18s film boiling.

a{

283 503-3 1090 1610 158P 1410 - - Fuel pin fractured into two Z 1 pieces during disassembling. OU A void was observed in the $f melted cladding in the broken $>

portion. J.,

v 304 503-4 1500 1550 1430 1590 1580 1620 - - Fuel pin fractured into two pieces. A large void was observed in the fuel and the cladding was melted.

392 503-5 1670 1100 1520 1540 - -

1.5 (0.15) 3.4 Cladding was melted exten-sively. Fuel was expelled from the pin and fragmented.

Oxidation of cladding was observed in a portion of the fuel plenum.

NEDO-24259-A (fren GEAP-25163-1)

Table 2.24 GENERAL ELECTRIC FUEL ROD SEGMENTS

• PSF TESTS Pellet Cladding Approximate Gap Exposure SAP Fuel Type mmlin. M W e% g-U Test

• Rod No.

14.4 Reference RfA 17 W5-2 0.229S.009 15.3 Reference RfA 17 OD07 2 0.299S.009 9.6 Reference Rf A 17 STR-137 0.229 4.009 9.1 Cu-barrier <

Rf A 1-7 OC08-4 0.2294.009 0.22SO 009 13.1 Cu-barriere Rf A 1-3 9C07-1 13.3 Reference RfA 1-3 STR-134 0.2294.009 0.17&c.007 14.0 Reference RfA 17 8D154 13.1 Reference RfA 1-3 OA06-1 0.17&c.007 15.3 Reference RtA 17 5005-5 C.2294.009 0.229 4.009 5.3 Zr hner 0 076 mm RfA 1 7 07B-2406 aRod o a = 12 52 mm f0433 nnenesA ciaomns mate te.csness = 0 864 men 10 C34 medes)

Diest RaA reactmty insert.cn acccNit test Rf A 13 Test Date Sco 1980 R1 A 17 Test Date Fee 1981 OPT ATWS tests CPT 1-1 scheested for June 1980.

Asl tdW mith 1 atenotchere gli MPa) He escoct DTS - 2406 Fuel - 3 etm. $L3 WPa) Fuel Rod Lett;th 966 rnm Q7.6 ini C0 C1 mm (0 0004 wu Co - Di!*uset bonded A3-11

NEDO-24259-A (from GEAP-25163-1) l Table 2.31 SRP IRRADIATION STATUS Highest SRP Average Segment Exposure Average Exposure Segmetet Tier (mwd /kg U) (MWdikg U) Date STR Bundle Top 10.7 12.7 April 1979 SRP-1 Middle Top 15.6 18.6 (Quad Cities 1)

Middle Bottom 15.6 19.4 Bottom 13.2 16.7 Bundle Average 13.8 Top 12.0 16.0 May 1979 SRP2 Middle Top 18.4 24.4 (Monticello)

Middle Bottom 20.8 27.4 Bottom 18.5 24.3 Bundle Average 17.4 Top 11.8 16.1 April 1979 SRP-3 Middle Top 17.1 22.0 (Millstone)

Middle Bottom 19.2 24.6 Bottom 17.6 23.6 Bundle Average 16.4 Table 2.52 SEGMENTS RETRIEVED DURING FOURTH RECONSTITUTION OF BUNDLE SRP 3 (MILLSTONE)

Cladding Estimated Average Wall He Pressure Bumup*

Segment Serial No. Design Features Thickness (mm) (MPa) (MWdIkg U)

Zr Liner (crystal bar) 0.71 1.7 13.4c S1 R 046 STR 049 Zr Liner (crystal bar) 0.71 1.7 20.0 DTC 2303 5 pm Cu-Barrier (on oxide) 0.86 0.3 5.6 DTC 2305 5 pm Cu Barrier (on oxide) 0.86 0.3 6.7 aCiaddmg heat treatment. recrystallization anneal; fuel density 95.5%; diametral gap 0.23 mm.

bEstimated segment burnups subject to revision following evaluation of *Cs gamma scan data.

CIop segment; peaklaverage bumup ratio approx 6mately 1.5.

l A3-12

NEDO-24259-A Attachment A4 (from GEAP-25163-2)

UC 78 March 1980  !

DRF No. J11102 DEMONSTRATION OF FUEL RESISTANT TO PELLET CLADDING INTERACTION PHASE 2 Second Semiannual Report, July-December 1979 Compiled by H.S. Rosenbaum Program Manager Approved: / {,

'J. S. Armijo, Manager Core Matarlais Technology Prepared for the Commonwealth Research Corporation under Subcontract 3-20-46 U.S. Department of Energy ,

Prime Contract DE-ACO2-77ET34001 (Formerly Contract EN-77-C-02-4473)

Printed in the United States of America Available from j National TechnicalInformation Service U.S. Department of Commerce l

5285 Port Royal Road l

Springfield, V A 22161 Price: Printed Copy $4.00; Microfiche $2.25 A4-1

l NEDO-24259-A i (from GEAP-25163-2) l LEGAL NOTICE This report was prepared by General Electric as an account of work sponsored by the U.S. Department of Energy (" DOE"). Neither DOE, members of DOE, nor GE, nor any person acting on behalf of either, including Commonwealth Edison Company and Commonwealth Research Corporation:

A. Makes any warranty or representations, express or implied, with respect to the accuracy, completeness, or usefulness of the information con-tained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of, any information, apparatus, method, or process disclosed in this report.

i e

. A4-2

NEDO-24259-A (from GEAP-25163-2)

TABLE OF CONTENTS Page ABSTRACT.......................................................................................ix C O N T RI B U TI N G AU T H O RS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

H I G H LI G H T S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AC K NOW LE DG E M EN TS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

1. I N T R O D U CT IO N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. TASK 1. NUCLEAR DESIGN AND CORE M AN AGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . .21 2.1 Objectives. . .. . .. ... .. . .. . .. .. . . . ..

. . . . . 2-1 2.2 Introduction. . . . . . . . . . ..... .. ... ... .... . . .

. 2-5 2.3 Energy Utilization Plan (EUP). ... ... .... ..... .. . .. .. ...

2-6 2.4 Power Ramp Simulation.... . . .. .. . .. . ... .... . . ... . .. .

3. T AS K 11. SU PPO RT T EST S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. 3-1 Objectives. . .,

5 3.1 . .. . . . . .... .

. 3-1 3.2 Subtaskil.1 Laboratory Tests... . . . .. . .

Subtask 11.1.1 Characterization and Stability. ... . .31 3.2.1 .

. . . . 3-12 3.2.2 Subtask 11.1.2 PCI Simulatic'i Tests . .

. 3-18 3.3 Subtask il.2 Licensing Tests. . . .. .... ... . . . .. .. .

Loss-of-Coolant Accident Simulation. .. .... . . . 3-18 3.3.1 .. .

Subtask 11.3 Fuel trradiation Tests. , . . .. . . . ... . 3-24 3.4 . .. .

3.4.1 Segmented Rod Irradiation Tests .. . . ... . .. . . 3-24 Fuel with Cladding Perforation.. . .. . .... . . .. . . .3-45 3.4.2 .

4. T AS K ill. D EM O N ST R ATIO N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Objectives . . . . . . .. ... . .. . . .. . . . . 4-1 4.1 .... . .. . .. ... .

4-1 4.2 Subtask 111.1 Design and Licensing of Demonstration Fuel. . .. . . ... ..

.. . ... . 4-1

~ 4.3 Subtaskill.2 Fabrication of Demonstration Fuel. ... .. .. . ..

. . . . . . 4-1 4.3.1 Zr. liner. . . . . . . . . .. ... .. .., . .. . ... .

... . . . . . 41 4.3.2 Cu-bar rier. . . ... ....... .. . .. . .

42 Subtask lit.31rradiation and Evaluation..... .. . . .

4.4

5. TAS K IV. L EA D T EST AS S EM B LI ES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DI ST R I B UTIO N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A4-3/A4-4

~

NED0-24259-A (from GEAP-25613-2)

LIST OF ILLUSTRATIONS Figure Title Page 2.21 Ramp Cell Locations, Cycles 6 and 7. . . .

.22 2.22 Ramp Cell Locations. Cycles 8 and 9. Driver Fuel Indicated by D. . . . . . .. ... .2-3 2.2-3 Allowable Pre-Ramp Locations for Special Barrier Bundles. . . . . . . 2-4 2.41 Operational Strategy. .... . . ... .. ... . .. . . . .. . .27 2.4-2 Typical EOC Ramping Schedule, Cycle 6/7. . . . .. . . . .2-8 3.21 Perforated Rod Simulator Test Apparatus. .... . . .. .... ... . . . . .3-3 3.22 The Refreshed Autoclave System Shown Scr ematically.... . .. ......... .. . ... .3-4 3.23 Photomicrographs of (a) low oxygen sponge and (b) crystal bar zirconium lined tubing before testing,(1), and after being tested in the simulator at 350*C in 7.0 MPa (1000 psig) steam for 3 days . . . . . . . . . . . . ... .... ..... ..... . ... .. ..... . .... ..... . 3-5 3.24 Photomicrographs of (1) low oxygen sponge and (2) crystal bar zirconium lined tubing af ter being tested in the simulator at 350'C in 7.0 MPa (1000 psig) steam for 12 days. (a) and (b) represent different locations of the same samples. ... . . ... .. .. .. ... . . . ....... . . . . 3-7 3.2-5 Corrosion Weight Gains for Zr liner Cladding and Reference Zircaloy-2 as a Function of Time at 350 *C and 400 *C in 7.0 MPa (1000 psig) Steam in the Simulator. . ... . .. . .... ... 3-8 3.2-6 Photomicrographs of (a) low oxygen sponge and (b) crystal bar zirconium lined tubing af ter being tested in the refreshed autoclave at (1) 350*C and (2) 400*C in 7.0 MPa (1000 psig)

Steam for 3 Days . . . . . . . . . . . . . . . . . . . ............. ... ...... .... .... ...... ........ . . 3-10 3.27 Photomacrographs ans' photomicrographs of specimens after being tested in the refreshed autoclave at 350*C,7.0 MPa (1000 psig) for 13 days:(a) inner surface visual appearance; specimens labeled L have the low oxygen sponge Zr liner while those labeled X have the crystal bar Zr liner; (b) crystal bar liner in the as-received condition; (c) crystal bar liner in the belt ground condition; low oxygen sponge in (d) as received;(e) 1 min etched; (f) belt ground conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. ..... . 3-11 3.2-8 Comparison of Knoop microhardness impressions for irradiated crystal bar zirconium liner and Zircaloy-2 cladding.(Fluence = 1.5 x 102: n/cm 2(E > 1 MeV), Irradiation Te m pe rat u re = 288

• C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... ..... ........ . . 3-13 3.2-9 Knoop Microhardness vs. Fast Neutron Fluence for Zirconium and Zircaloy-2.. . . . . . ..... . . 3-14 3.2 10 Remote Expanding Mandrel Loading System (REMLS)....... .. .. .... . .... ............ . . 3-16 3.3-1 Temperature as a Function of Time for Simulated LOCA Testing... . .. . ...... . . .... .. . 3-19 3.32 Typical Computer Oqtput for LOCA Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . 3-21 3.3-3 LOCA Specimens Tested at 5.2 Mpa Hoop Stress Original Tubing Outer Diameter = 12.3 mm. . . . 3-22 a

A4-5

NEDO-24259-A (from CEAP-25163-2) 3.3-4 LOCA Specimens Tested at 6.9 MPa Hoop Stress . . . . 3-23 3.4-1 Ramp Test Sequence to Investigate Effect of Short(6 Hours) Standardization Phase.

Ramp Test Sequence A. . . . 3-28 3.4-2 Ramp Test Sequence B. . . . . 3-29 3.43 Recorder Chart Output, SRP 2/21. .. . . 3-30 3.4-4 Ramp Sequence A - Ef fect of Standardization Time. .. . . . 3-32 3.4-5 Copper Bartier(Nonbonded) - Total Experience. . . .. . 3-33 3.4-6 Ramp Sequence B Results. ... .. . . .. . .. . 3-35 3.4 7 Nondestructive Test Results - Cu-barrier Rod SRP-2/1. . . . . . . . 3-37 3.4-8 Nondestructive Test Results - Zr liner Rod SRP-3/35. .. . .3-39 3.4-9 Nondestructive Test Data - Reference Rod SRP-2/14. . ....... . .. . . 3-41 3.4-10 SRP Segment Cladding Strain Due to Power Ramp Testing . . .. . . . . . . 3-44 3.4 11 Fabrication Flow in the High Power Region of Zr. liner Fuel Rod SRP-3/35. .. . . 3-46 3.4-12 Microcracks in the High Power and High Strain Region of Zr-liner Fuel Rod SRP-3/35. . .. . . 3-47 3.4 13 Locations of Microcracks on Inner Surf ace of Zr-liner Fuel Rod SRP-3/35.. . . . . . 3-48 3.4 14 Perforated FuelTest Rod. .. . . . .. . .. .. . . . .. . . . . . 3-49 3.4-15 Correlation Between Loop Activity and Loop Pressure During Steady State Operation. .. .3-52 3.4-16 Correlation Between Loop Activity and Loop Pressure Shortly After Reactor Shutdown. . . . . . . 3-53 3.4-17 Trend of loop 2 Coolant Activity Through First Two Cycles . . . .. .. ... . .... .. . .. 3 54 4.3 1 Example of Low-Oxygen Sponge Zirconium-Lined Tubeshell Showing the Zircaloy Zirconium lnterface Prior to Tube Reduction . . .... . . .. .. . . . . 4-2 4.3-2 Electroless Copper Plated on Oxidized Zircaloy, Viewed in Tapered Section.

(a) WLM (b) CRD. . . . ... ....... .. ... ........ ... . ..... . . . . .. . .. . . 4-3 4.3-3 Same as Figure 4.3-2 at 1000 x . . . . . .. . .. .... .. ...... . .... ... ...... .. . 4-4 4.3-4 Scanning Electron Micrographs of Copper Surfaces Electroless Plated on Oxidized Zircatoy.

(a) WLM (b) CRD . . . . . . . . . .. . ... ... . .. .. .. ......... . . . . .. . .45 4.3-5 Copper Electroless Plated on Oxidized Zircaloy Viewed on Polished Cross Sectioned and Etched.(a) WLM (b) CRD. . ... . . ... . .. ... ..... . 4-6

-4.3-6 Zircaloy Tubing Surfaces After Removal of Copper in Dilute aq. HNO3.

(a) WLM (b) CRD . . . . . . . . . . . . . . . . . .. .. ... . . .. . . .. .. .. .4-7 A4-6

NEDO-24259-A (from GEAP-25163-2)

LIST OF TABLES Title Page Table initial Energy Utilization Plan for PCI-Resistant Fuel Demonstration in Quad-Cities Unit 2. . . . 2-5 2.3 1 Reload Bundle Requirements for Demonstration Cycles (Preliminary).... . .. .. 2-6 2.41 .. .

Preliminary Reference Loading Pattern Cycle Exposure Capabilities . . . 2-7 2.4 2 . . ..... . .

2.4-3 Peak LHGR Achieved During Ramping........ . .......... ... . .. . ... .. .......28 Weight Gain Data of Samples Tested in the Simulator at 350 and 400 *C . . . . . . . . . . . . .. ........ 3-6 3.2 1 3.2 2 The Weight Gain (mg/dm') of Cladding Samples Tested in the Recirculating Autoclave at 350 and 400 *C. . . . . . . . . . . . . . . . . . . . . . . . . . . .... .. .. .... .... . ...... .. . ..... 3-9 3.2-3 Weight Gain (mg/dm') of Samples Tested in the Re-circulating Autoclave Test Conditions:

350 *C,7.0 M Pa (1000 psig),13 Days. . . . . . . . . . . . . . . . . . . . . . . . ...... . . . .. ....... ..... 3-9 3.2-4 Tensile Tests of Zircor. lum Irradiated at 327'C to Fluence 6.8 x 10" n/cm' (E > 1 M eV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . ..... . . ........... . . . . . . . . 3-15 3.31 LOC A Te s t Su m ma ry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 4 3.41 SRP Irradiation Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...... .......... ... ..... . . . . . . 3-25 3.4-2 Description of Fuel Rods Ramp Tested in 1979. . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . 3-26 3.e3 1979 SRP Pamp Test, Program Result Summary. . .. . ... ...... .... . . . . . . . . . . . . . . . 3-31 3.4-4 1978 Ramp Tests - Nondestructive PIE Results Summary.. ...... .. .. .. . .. .. .. . . . . . . . . . 3-36 3.4 5 Cladding Strains - Zr Liner Rods . . . . . . ..... ... ... ..................................343 3.4 6 Correlation Between Microcracks and Cladding Duty in SRP.3/35. . . . . . . . . . . . . . . . . . . . . . . . . . . 3-45 3.4 7 Perforated Rod Design Details... ... . .. . . . .. ......................... ............ ... . . . 3-50 3.48 Special Reactor Startup Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 50 3.4-9 Water Sample Activity Analysis - Data Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-55 A4-7/A4-8

NEDD-24259-A (from GEAP-25153-2)

ABSTRACT This program has as its ultimate objective the demonstration of an advanced fuel design that is resistant to the failure mechanism known as fuel pellet-cladding Interaction (PCI). Two fuel concepts are being developed for possible demonstration within this program: (a) Cu-barrier fuel and (b) Zr-liner fuel.

These advanced fuels (known collectively as " barrier fuels") have special fuel cladding designed to avoid the harmful etlects of localtzed stress and reactive fission products during reactor service. Within the work scope of this program one of these concepts will be selected for demonstration in a commercial power reactor.

In the current report period the nuclear design of the demonstration was begun. The design calls for 132 bundles of barrier fuel to be inserted into the core of Quad Cities Unit 2 at the Beginning of Cycle 6. The nuclear design uses the scheme which was developedin PHASE 1 of this program. Near the end of Cycles 6, 7, 8 and 9, sixteen bundles of demonstration fuel will be power ramped to demonstrate resistance to PCI. Thus, 64 bundles will be ramped in this manner.

Laboratory and in-reactor tests were started to evaluate the stability of Zr liner fuel which remains in service after a defect has occurred which allows water to enter the rod. Results to date on Intentionally defected fuelIndicate that the Zr-liner fuelis not rapidly degraded despite ingress of water.

Irradiation tests of barrier fuel, including power ramping, have shown that Zr-liner fuel has excellent PCI resistance at burnup levels to 16.6 mwd /kg U despite plastic deformation in excess of 0.5% Induced by the severe power ramp test. Cu-barrier fuel with copper plated onto etched Zircaloy (no inter-mediate oxide diffusion barrier) tends to lose its resistance to PCI at exposures >14 mwd /kg U. However, it continues to perform better than does reference fuel.

Four lead test assemblies of barrier fuel (two of Zr-liner and two of Cu-barrier) are presently under Irradiation in 0 :ad Cities Unit 1 and have achieved a burnup of approximately 6.5 mwd /kg U thus far.

A4-9/A4-10

NEDO-24259-A (from GEAP-25163-2)

CONTRIBUTING AUTHORS R. B. Adamson, Nuclear Fuel and Services Engineering Department,(NFSED)

D. E. Allen, Wilmington Manufacturing Department,(WMD)

J. A. Baumgartner, Nuclear Fuel and Services Engineering Department,(NFSED)

R. E. Blood, Nuclear Fuel and Services Engineering Department,(NFSED)

R. E. Brown, Nuclear Fuel and Services Engineering Department,(NFSED)

8. Cheng, Nuclear Fuel and Services Engineering Department,(NFSED)

J. H. Davies, Nuclear Fuel and Services Engineering Department,(NFSED)

D. K. Dennison, Nuclear Fuel and Services Eng'neering Department,(NFSED)

R. E. Donaghy, Wilmington Manuf acturing Department, (WMD)

E. L Esch, Nuciear Fuel and Services Engineering Department,(NFSED)

W. J. Grubb, Corporate Research and Development,(CRD)

C. C. Guitton, Nuclear Fuel and Services Engineering Department ,(NFSED)

J. O. Hegland, Nuclear Fuel and Services Engineering Department ,(NFSED)

G. H. Henderson, Nuclear Fuel and Services Engineering Department,(NFSED)

R. D. Jones, Nuclear Fuel and Services Engineering Department,(NFSED)

R. J. Mack, Wilmington Manufacturing Department,(WMD)

H. H. Paustian, Nuclear Fuel and Services Engineering Department,(NFSED)

M. B. Reynolds, Nuclear Fuel and Services Engineering Department,(NFSED)

E. Rosicky, Nuclear Fuel and Services Engineering Department,(NFSED)

J. R. Thompson, Nuclear Fuel and Services Engineering Department,(NFSED)

R. P. Tucker, Nuclear Fuel and Services Engineering Department,(NFS9 S. B. Wisner, Nuclear Fuel and Services Engineering Department, (NF5c c A4-ll/A4-12

NEIm-24259-A (from GEAP-25163-2)

HIGHLIGHTS .

• Power ramp testing of barrier fuel continues to show superior PCI resistance compared to the reference conventional fuel.

• The Zr-liner fuel tested at lead burnup (16.6 mwd /kg U) successfully sustained diametral plastic strain of approximately 0.5%; comparable reference fuel failed at much lower plastic strain in these ramp tests.

• Many crack nuclei were found on the inner surf ace of the highly strained regions of the Zr liner cladding.

These crack nuclei were uniformly limited in length to approximately 12 pm.Thus, while cracks nucleated at high powers they did not propagate into the zirconium liner despite the large strain.

• Although Cu-barrier fuel out performs reference fuel, the design with copper plated onto etched Zircaloy (i.e. no oxide layer between copper and Zircaloy)is not immune to PCI f ailures at burnups >14 mwd /kg U.

The tests are consistent with the hypothesis that interdiffusion of copper with Zircaloy tends to reduce the resistance to PCI.

• Laboraterf tests of the stability of Zr-liner fuelindicate that under conditions which simulate a fuel clad-ding perforation the zirconium liner oxidizes rapidly and that the reaction slows markedly when the oxidelmetal interface enters the Zircatoy.

• An in-reactor test of deliberately perforated Zr liner fuel is in progress with early results showing no sign of rapid degradation of the cladding.

• Four lead test assemblies (LTA's) of barrier fuel are under irradiation in the core of Quad Cities Unit 1 since February 1979, and they have achieved a burnup of approximately 6.5 mwd /kg U through December 1979. These assemblies include both Cu barrier and Zr-liner fuel.

l A4-13/A4-14

NEDO-24259-A (from GEAP-25163-2)

ACKNOWLEDGEMENTS The help of the following people is gratefully acknowledged:

J. S. Armijo of the GE Nuclear Fueland Services Engineering Department for his continued encouragement and leadership.

M. L. Ishikawa of the Japan Atomic Energy Research Institute for his help in implementing the RIA tests which were reported in this program.

W. V. Johnston and R. VanHouten of the FuelBehavior Research Branch of the U.C. Nuclear Regulatory Commission for their continued interest in this pro-gram and for their help in effecting safety tests for barrier fuel.

W. M. Kiefer of the Commonwealth Edison Company for his continuedinterest and for his participation in the Program Steering Committee.

P. M. Lang of the U.S. Department of Energy for his support and for his par-ticipation in the Pingram Steering Committee.

A. S. Mehner of the U.S. Department of Energy (on leave from EG&G idaho, Inc.)

for his encouragement and for helpful discussions.

D. R. O'Boyle of the Commonwealth Edison Company for his ective support from the bspinning of this program and for his critical review of the manuscript o ' this report.

A4-15/A4-16

NED0-24259-A (from GEAP-25163-2)

1. INTRODUCTION An important mechanism for fuel failure in power reactors involves the direct interaction between the ir.

radiated uranium fuel, including its inventory of fission products, and the Zircaloy fuel sheath. This fuel failure mechanism is known as " fuel / cladding Interaction" or " pellet-cladding interaction" (PCI). This fuel failure mechanism is known to occur in all types of power reactors fue'ed with uranium oxide which is sheathed in Zir-caloy. Building upon the General Electric Company's efforts from 1969 to 1977 to understand the PCI phenomenon and to develop potential remedies, this program was designed to exploit two remedies which General Electric (GE) had already identified as having good potential for success:(a) Cu-barrier fuel and (b) Zr.

' liner fuel. These f uel concepts are known collectively as barrier f uel, and they have been previously described."

This program leads ultirqately to the large-scale demonstration of one of the two remedy concepts discussed here: Cu-barrier or Zr-liner. The overall program has been divided into three phases:

PH ASE 1. Design and Supporting Tests PH ASE 2. Large-Scale Demonstration PH ASE 3. Demonstration Exter ding to High Burnup PHASE 1 now has been completed and its final report issued.a PHASE 1 included:

1. A generic nuclear engineering study to show that the demonstration is feasible in a reactor of the BWR/3 type.

2. Laboratory and reactor tests to verify the PCI resistance of the Cu-barrier and the Zr-liner fuel types.

3. Laboratory tests of Darrier cladding under simulated loss-of-coolant accident (LOCA) conditions.

4 Design, licensing documentation, fabrication and preirradiation characterization of four lead test assemblies (LTA'st for irradiation in the Quad Cities Nuclear Power Station Unit 1, beginning in Cycle 5. Irradiation of the LTA's was begun in February 1979.

PHASE 2 continues the work of PHASE 1, and includes:

1. Selection of the fuel design for the demonstration.

2. Nuclear design and core management of the demonstration, expanding from the generic feasibility study in PHASE 1 to a specific reactor and target cycle, including bundle nuclear designs. As presently contemplated, the reactor and target cycle are Quad Cities Unit 2, beginning with Cycle 6 (tentatively scheduled to begin in January 1982).

3. Design, licensing documentation, and manufacturing of the demonstration fuel.

4 The demonstration per se; i.e., the Irradiation (including specially designed power ramps to demonstrate PCI resistance). As presently perceived, PHASE 2 will include the irradiation through 1984 and is intended to include two full demonstration cycles and end-of-cycle ramps (depending on reactor schedule).

5. Continued irradiation and evaluation of the four LTA's.

6. Cc.ntinued testing of barrier fuel to assure PCI resistance at burnup levels relevant to the demonstration.

PHASE 3 is intended to extend the demonstration to high burnup. It is contingent on successful comple-tion of PHASE 2, and details of the scope have yet to be defined.

A 's-17

NED0-24259-A (from GEAP-25163-2) l The first semiannual progress report for PHASE 2 has been issued previously' and includes work done in the first half of calendar year 1979. This is the second semiannual progress report for PHASE 2; it includes work during July-December 1979.

The task structure of PHASE 2 is as follows:

Task 1. Nuclear Design and Core Management

• Design of the core and the licensing of the demonstration including the mode of operation to power ramp the demonstration of fuel bundles in the test cells.

• Core management activities associated with the demonstration (but excluding that effort which would be normally required M the absence of the demonstration).

Task II. Support Tests Subtask 11.1 Laboratory Tests

• Characterization of barrier fuel and assessment of barrier stability.

• Simulated PCI tests.

Subtask 11.2 Licensing Tests

• Tests to assess behavior of barrier fuel under accident conditions:(a) reactivity-initiated accident (RIA) and (b) loss of-coolant accident (LOCA).

Subtask 11.3 Fuel Irradiation Tests

• Power ramp tests in a test reactor to evaluate the PCI resistance of barrier fuel at various burnup levels.

• Stability of barrier fuel with a through-wall defect.

Task 111. Demonstration Subtask 111.1 Design and Licensing of Demonstration Fuel

• Design and licensing activities associated with the barrier fuel itself.

• integration of design and f abrication.

Subtask ill.2 Fabrication of Demonstration Fuel

• Fabrication of 132 demonstration bundles of barrier fuel.

l l

l A4-18

NEDO-24259-A (from GEAP-25163-2)

Subtask !!!.3 Irradiation and Evaluation

• Monitoring power history.

• Evaluation of performance of the demonstration fuel and analysis leading to engineering inferences.

Task IV. Lead Test Assemblies

• Evaluation of the in-reactor performance of the LTA's including correlations with power history.

A4-19/A4-20

NED0-24259-A (from GEAP-25163-2)

2. TASK 1. NUCLEAR DESIGN AND CORE MANAGEMENT (H. H. Paustlan and R. E. Brown, NFSED) j 2.1 OBJECTIVES

1. Design the demonstration irradiation for a specific reactor and target cycle (tentatively Quad Cities 2, Cycle 6) including technical evaluation of the fuel ioading pattern and the reactor opera.

tional mode to effect both the demonstration and the efficient production of electricity as dictated by the needs of the Commonwealth Edison Company (CECO).

2. Develop and implement a core management plan for the demonstration irradiation.

3. Design the demonstration fuel bundles.

4. Provide the nuclear licensing support required for the demonstration irradiation and the associated reactor operating plan.

5. Work with CECO a) to define the operational constraints imposed by the reactor owner-operator, and b) to obtain mutually satisfactory arrangements required to conduct the demonstration irradiation.

2.2 INTRODUCTION

in PHASE 1 a generic nuclear design was done8 8 to determine the feasibility of a large-scale demonstra-tion of PCI-resistant fuelin an operating commercial power reactor of type BWR/3.The generic design involved 132 bundles of the PCI-resistant fuel (i.e., barrier fuel), of which 64 were to be power ramped.These 64 bundles were divided into four groups of 16 with one group to be ramped at the end of each of four successive reactor cycles. Thus, taking Quad Cities Unit 1, Cycles 6-9 as an example of a BWR/3 core on which to base the generic study, one group of 16 bundles would be ramped at the end of Cycle 6, another at the end of Cycle 7, etc. In each of these cycles the bundles to be ramped were placed into four particular cells (one cell in each quarter core);

these cells comprised a single cruciform control blade and four demonstration bundles surrounded by a buffer zone of one row of low reactivity conventional fuel bur'dles. In each cycle the control blade in these assemblies was held ~70-100% inserted until very near the end of the cycle, when the blade was withdrawn in increments of 0.457 m (1.50 feet) to effect a controlled and localized power ramp.

This generic design was studied in PH ASE 1, and calculations were performed to evaluate cycle exposure capability, reactivity margins, critical control rod patterns, core response to assumed accidents and transients, and core response to the power ramping of the demonstration fuel assemblies.8 8 Having shown in PH ASE 1 the feasibility of a large-scale demonstration in an operating reactor, attention has been turned to the detailed design required for the demonstration in a specific reactor and cycles, Quad Cities Unit 2, Cycles 6 through 9. However, the basic concept utilizing special ramp cells surrounded by a buf fer zone was retained from the generic study. The locations and configurations of the special ramp cells are shown in Figure 2.21. In the later demonstration cycles (Cycles 8 and 9)it is possible that fresh fuel bundles will have to be used within the ramp cells to boost the power to obtain a good demonstration of PCI resistance during the power ramps, in that event each quarter core would have two specia! ramp cells, each with two demonstration fuel bundles and two fresh driver fuel bundles as shown in Figure 2.2-2. In accord with the generic study the demonstration bundles which are to be ramped in a particular cycle are loaded in the special ramp cells at the beginning of that cycle; bundles which are scheduled to be ramped in subsequent cycles are loaded near the core periphery in the locations indicated in Figure 2.2-3.

A4-21

l (fr GE.iP- 5 63-2) 7 e c < o8+88+88+88+88+8o a mMMMMM8+Mo o a+s f M 8+8 M B+8 8+8 8+8 8+8 8e o 84 M A E 8+8 8+8 84 84 8+8 M M M M oM8+8M8fM8+88+88f848+8M84Mo 8+8 M M 84 8 8+8 8+8 8f 8+8 8+8 8+8 8+8 8+8 8+8 8+

8+ M 8+8 8+8 8f M M 8+8 8+8 8+8 8+8 8f 8+8 8+8 84 8+8 84 8+8 8f 84 M 84 8+8 8+8 8+8 M M 8f M +8 8+88+88f8+8848+884848+8f84884848+8 Bf 84 8+8 8+8 8+ 8+ 84 84 8+8 84 M 84 8+8 8+8 8+8 M8+aafa+88+888+88+88+88+a8+aaf8f BfMMEM8f8+8848+8MMEM 848+8848484848f8+88+8M8f M M 8f 84 8+8 8f 8f M M l 8+8888+88+88+8 BWR/3 724 BUNDLES l

Figure 2.2-1. Ramp Cell Locations, Cycles 6 and 7 l

A4-22 l

m:= :L l R y cett o 80 bbbbbbo

+ 4888f8888888884o o888+eME8888888BE!!E888o 88888+88888888888fM888888 E o8BHE8BB8888888oB888825EB8o 888888888888E88888888888M8BBB 888888888888888888888888888888 888888888888888888888888888888 888888gB8888888888888888888888 888888288888888888888888888888 88 ME88888888888888888H 8 88888888888888888888888888 888BHB8BBB8888BMB888 /

88 M E 84 8 84 E M E 8888888888 BWR/3 724 BUNDLES Figure 2.2-2. Ramp CeII Locations, Cycles 8 and 9. Driver FuelIndicated by D A4-23

NED0-24259-A (from GEAP-25163-2)

OiO OiO O CJO O O O 00155'sB WEYY WE OO O 5 bO00 YEO Od O O C C C D Obd O

BI8888888888888888888888E8 0 0 0 D 0 O

B288888888888888888888888888E8 C DO OO YO DO D DE O O O Q 00 DO C 8:88888888888888888888888888:8 0 bO EO d O DD 0 0 D 000  ! ~

BC BIB 88888888888888888888838 88888888888888888GB888

'8M8888BBB888M 55100 M

1 00555E55+00lO C D D O O'O O E ALLOWA8LE BUNDLE LOCATIONS Figure 2.2-3. Allowable Pre-Ramp Locations for Special Barrier Bundles A4-24

NEDO-24259-A (from GEAP-25163-2)

At the beginning of the design work in PHASE 2 it is convenient to define the nomenclature that will be used. The cells for which the end of cycle power ramps are planned are called " ramp cells". The 132 bundles of barrier fuel (i.e. the PCI. resistant fuel) to be demonstrated are called the " demonstration fuel bundles". Of these, the 64 scheduled for power ramps in the special ramp cells are called "special demonstration bundles" or "special barrier bundles"; while the 68 remaining are called " standard demonstration bundles" or " standard barrier bundles". In the generic study the special demonstration bundles had a special nuclear design to in-crease the power change near the wide-wide corner of the bundle (i.e. those fuel rods nearest the control blade axis) during the end.of. cycle power ramp. Somewhat dif ferent nomenclature was used in the PH ASE 1 reports 2-4 A prerequisite to the nuclear design is a realistic energy utilization plan (EUP). A reference EUP was ob-tained f rom CECO, and preliminary reference loading patterns for Cvcles 6 through 9 were derived. Simulated power ramping studies for each of the four demonstration cycles (6 through 9) were also done. Each of these is discussed in the following paragraphs.

2.3 ENERGY UTILIZATION Pl.AN (EUP)

Table 2.3-1 shows the energy utilization plan which is anticipated for the demonstration. Note that these are full power cycle exposure capabilities; no end-of cycle power coastdowns are included. Quad-Cities Unit 2 has just completed an end-of cycle coastdown for Cycle 4, and a similar end-of-cycle coastdown is anticipated for Cycle 5. Thus, at the beginning of Cycle 6 the fuel remaining from previous cycles has relatively low re-activity. In the current analyses of the demonstration it was assumed that no coastdown would occur in Cycles 6-9. Cycisa 10 through 13 are listed because it is anticipated that by the end of Cycle 13, all of the demonstration f uel will have been removed f rom the core and all ef fects of the demonstration will have been removed. It is likely that PHASE 3 of this program will involve retaining some of the demonstration fuel for extended burnup, but ex-tended burnup has not been considered in the fuel cycle comparisons. Thus, by considering cycles through Cycle 13, any fuel cycle comparisons done between the demonstration loading patterns and a normal loading pattern will be on a consistent basis. The normal loading considered here is one involving the control cell core concept.5 This Energy Utilization Plan includes higher cycle exposure capability requirements then did the EUP utilized in the PHASE 1 generic study.8 Thus, it was necessary to significantly revise the loading strategies developed in PHASE 1. However, the test cell locations, buffer zone locations, and incubation of the special demonstration bundles one row from the core periphery, were retained. In the preliminary reference loading pat-terns, the same number of bundles and enrichment of the special demonstration bundles to be ramped were also retained.The size of the reload batches and in some cases the enrichment of the reload fuel were changed, however, to meet the EUP, The demonstration fuel loading patterns have progressed through a number of itera-tions, as the EUP was evolved and as Cycle 4 was coasted down beyond previously calculated end-of-cycle ex-posures. The detailed design is being developed, and some changes in loading patterns can be expected.

Table 2.3-1

!NITIAL ENERGY UTILIZATION PLAN FOR PCI-RESISTANT FUEL DEMONSTRATION IN QMD-CITIES UNIT 2 Cycle Exposure Capability Cycle (MWdIkg U)

'6 6.3 Demonstration 7 7.5 Cycles 8 7.5

,9 7.5 10 7.5 11 7.5 12 7.5 13 7.5 A4-25

NEDO-24259-A (from CEAP-25163-2) 2.4 POWER RAMP SIMULATION To find what modifications would be required in standard bundle designs to raise peaking to values where the resulting linear heat generation rates in the fuel would adequately demonstrate its PCI resistance, one of the loading patte;.1 was selected for ramping calculations. Table 2.4-1 shows the reload bundle requirements of the loading patterns used in the ramping simulations. Table 2.4 2 shows the cycle exposure capability obtained from these loadings. The ramping simu.ations were done using the three-dimensional coupled thermohydraulic-nuclear BWR core simulator program. A Haling analysis was done with the ramp cell blades withdrawn to Notch Position 18 (48 = fully withdrawn) until the end of full-power capability with those blades inserted was reached.

This point is called EOC'(see Figure 2.4-1). The ramp cell blaces were then withdrawn in 0.457 m (1.50 f t) in-crements interspersed with periods of coastdown such that reactor power would not exceed 100% following the ramp. To estimate the powers obtained in fuel after rod pull, xenon was held constant following the rod pull. It was then allowed to reach its new equilibrium level and was then followed by the next coastdown interval. This procedure was repeated until all ramp cell blades were fully withdrawn. Figures 2.41 and 2.4 2 illustrate the operating strategy.

Table 2.4-3 shows the maximum power obtained in the ramped special demonstration bundles for each of the four demonstration cycles. Note that these estimated peak power levels include the effect on bundle local power distributions of extended periods of exposure accumulation with the adjacent control rod inserted (con-trol blade history or CBH). Based on the work in PHASE 1 it can be anticipated that special nuclear design of the demonstration bundles can increase the peak power levels attainable by 10-15%. Such bundle designs are in progress.

Table 2.41 RELOAD BUNDLE REQUIREMENTS FOR DEMONSTRATION CYCLES (PRELIMINARY)

No. of Reload Enrichment Cycle Bundles Cladding (Bundle Avg) Comments 16 Barrier Special demonstration 16 Barrier 2.39 }i 2.65 bundles to be 6 32 < Barrier 2.82, power ramped 68 Barrier 2.82 100 Conventional 2.82 7 168 Conventional 2.65 8 184 Conventional 2.65 g

56 Conventional 2.65 152 Conventional 2.82 A4-26

NEDO-24259-A (from GEAP-25163-2)

Table 2.4 2 PRELIMINARY REFERENCE LOADING PATTERN CYCLE EXPOSURE CAPABILITIES Cycle Exposure

• Cycle Exposure

• Total Cycle 4 Total No. of from BOC to EOC' from EOC' to EOC Exposure (

Reload Bundles (mwd /kg U) (mwd /kg U) (MWdikg U)

Cycle 232 6.28 0.19 6.47 6

7.43 0.15 7.58 7 168 184 7.08 0.30 7.38 8

7.27 0.37 7.64 9 208

• Halin0 analyses with ramp cell blades withdrawn to notch position 18 from BOC to EOC' and with all ramp cell blades completely withdrawn from EOC' to EOC. See Figure 2.4-1.

NORM AL OPER ATION R AMPING O F

! - 375 fpd  :  : 8-21 fpd ->

l BOC = BEGINNING OF CYCLE 3 100 -

EOC = ENO OF CYCLE fpd = FULL POWER DAYS P Alt.OWABLE RANGE OF

$ BLADE INSERTION e 75 -

l5 ///// /

50 -

25 -

l I BOC EOC* EOC Figure 2.4-1. Operational Strategy A4-27

NEDO-24259-A (from GEAP-25163-2) too - - -

_ 4 POWER LEVEL 3 E

=

e o

C

~

6 8E E >

12 u-g -

w w Q 12 g CONTROL BLADE VERTICAL POSITION O $g e, So - - - - - - - - -

18 m 8 j$-

k - ----- -

24 o 5 e sy 3o a i

r $

36 $2 o e

- = - 42 0 I I  ! I I I '

e o 2 4 6 8 to 12 EOC* DAYS (full power days) EOC Figure 2.4-2. Typical EOC Ramping Schedule, Cycle 617 Table 2.4-3 PEAK LHGR ACHIEVED DURING RAMPlNG W W Corner Rod Blade Movement Peak Axial Nodal Linear Heat Generation Rate for Highest Peak Bundle Fuel Exposure Af ter Blade Movement Cycle LHGR Location

• Segment b (mwd /Fg U) kWim (kWitt) 6 24 to 30 (8, 8) 11 5.7 35.1 (10.7) 7 24 to 30 (8, 8) 11 10.0 33.1 (10.1) 8 30 to 36 (9, 6) 8 18.1 30.5 ( 9.3) 9 24 to 30 (9, 6) 11 26.5 26.6 ( 8.1) a Utili2ing the & fold symmetry of the core. the bundle locations are designated t?y Considering the upper left quadrant (see Figures 211 aM 2 2@ and counting bund!e rows from left to right and then from top to bottom.

DAntal fuel segments correspond to core node designat6ons which are numbered from the bottom 1 to 24. Thus the axial segment 1 cor. ,

responds to the bottom 6 inches (153 mm) of the core; segment 24 is the uppermost 6-ench (151mm) segment of the fuel column. .

I T

s e.

\

A4-28

NEDO-24259-A (from GEAP-25163-2)

ACKNOWLEDGEMENTS

. The contributing authors gratefully acknowledge the contributions of their colleagues to the work reported in Section 2:

R. L Crowther and P. J. Savola for their encouragement and direction.

P. Wei for performing the nuclear analyses of the bundle designs and for assistance in the ramping simulations.

J. S. Gunz and D. K. Cheng for their assistance in developing the nuclear assumptions and reference point for the start of the nuclear design.

l i

i i .'

A4-29/A4-30

NEDO-24259-A (from GEAP-25163-2)

3. TASK 11. SUPPORT TESTS 3.1 OEJECTIVES

1. Assess the long-term stability of the advanced fuel and develop supporting information needed for licensing.

2. Develop materials performance data needed to support the demonstration in a commercial power reactor.

3. Assess Cu-barrier and Zr. liner fuel performance under Loss of Coolet Accident (;.OCA) and Reac-tivity Initiated Accident (RIA) conditions.

4. Determine the capability of the advanced fuel to resist PCI.

5. Assess the in-reactor behavior of barrier fuel with cladding perforation.

6. Develop data needed to justify recommendation of a primary PCI-resistant fuel design for the demonstration and to maintain a viable backup design.

3.2 SUBTASK 11.1 LABORATORY TESTS 3.2.1 Subtask 11.1.1 Characterization and Stability 3.2.1.1 Oxidation of Zirconium-Lined Zircaloy (B. Cheng, J. O. Hegland, and R. B. Adamson, NFSED) 3.2.1.1.1 Introduction The use of a metallurgically bonded zirconium liner on the inner surface of Zircaloy-2 fuel cladding has been shown in ex reactor mandrei tests (Subtask 11.1.2) and by in-reactor power ramp tests (Subtask II.3) to in.

crease resistance to PCI. Since zirconium can oxidize more rapidly than Zircaloy 2 in steam and water en.

vironments in the temperature range of intereste (288-400*C). It is important to determine whether the Zr liner fuel can remain stable in the event that the cladding is breeched and water (steam) has entered the fuel rod. In this subtask laboratory tests are used to study this effect under conditions wbre parameters of the experiment can be varied. and in Subtask 11.3.2 an in-reactor experiment is in progress.

The ingress of H2O into a fuel rod is expected to result in a steam / hydrogen mixture. The entering water (initially at approximately 288'C,7.0 MPa) will be flashed into the vapor phase as it encounters the hotter fuel rod interior. The outer surface temperature of the UO2 pellets will be ~650*C, while the inner surface temperature of the fuel ciadding (i.e. that of the zirconium liner) will be in the range 300-400*C. Oxidation of the fuel and the zirconium is expected to occur and some hydrogen will be produced.

The aim of the present experiment was to study the corrosion resistance of zirconium-lined cladding in an environment which simulates that in a failed fuel rod. The corrosion resistance of the barrier cladding in pure

- steam was also investigated.

3.2.1.1.2 Experimental Procedure Full ring specimens 2.5 cm long were prepared from both the crystal bar and low oxygen sponge Zr liner cladding. The specimens lined with crystal bar zirconium were from a single tube, as were those lined with low oxygen sponge zirconium. These tubes were manufactured by General Electric's Wilmington Manufacturing Department (WMD) in 1977. The inner surface was grit blasted and etched.

A4-31

NEDO-24259-A (from GEAP-25163-2) 1 After samples were cut from the tubes, they were cleaned in soapy water in an ultrasonic bath for 5-10 min. and then etched to remove ~ 0.003 mm (~ 0.0001 in.) of zirconium.

The experimental apparatus, which produces a test condition simulating that of a fuel rod with a cladding perforation is shown schematically in Figure 3.2-1. A reservoir of water is maintained at 288*C, 7.0 MPa (1000 psig). Two separate temperature chambers are interconnected: UO2 pellets are maintained at temperature T, and the t 3rrier tubing test specimens are held at T 2. Temperature T, is 650 *C and T2 is the test temperature of interest in the range 300-400*C. Initially, the UO,is equilibrated at T, and the barrier tubing specimens at T 2; both chambers have an environment of He at 0.3 MPa (3 atm). The test starts with the admission of steam from the water reservoir into the chambers with UO, and cladding tube specimens. The flow of steam is through an orifice, which is typically 0.13 mm diameter. The steam reacts with the cladding at T2while simultaneously reacting with the urania at T,. The entire test is in a relatively small volume where H, remains to af fect the reac-tions. The environment changes as the reactions proceed. The tests were conducted with T, at 650*C and T2 at 350-400 *C for various durations.

Corrosion tests were also carried out in a refreshed autoclave shown schematically in Figure 3.2-2. The test temperature and pressure were 350-400 *C and 7.0 MPa (1000 psig), respectively. Due to the nature of the re-circulation system, the hydrogen generated from corrosion of the test samples lef t the autoclave rapidly and was removed from the feedwater with argon, which was bubbled through the water in the feedwater tank.

Corrosion rates in both tests mentioned above were determined by weight changes and by metallographic examination.

3.2.1.1.3 Results and Discussion (A) Simulation Tests The specimens tested in the simulator at 350 *C for 3,12 and 36 days all exhibited white powdery ap-pearance on the inner zirconium liner surfaces. Tne outer surfaces of all specimens and the reference Zircaloy-2 tubing specimens showed the typical black oxide color. The weight gain data shown in Table 3.2-1 indicated that the low oxygen sponge liner has slightly better corrosion resistance than does the crystal bar liner.

Metallographic examination of untested specimens showed that the thicknesses of the barriers (Zr-liner) were 0.0025 0.0001 and 0.0026 z 0.00007 inches (63.5 2 2.5 and 66.0 21.8 pm) for crystal bar and low oxygen sponge samples, respectively, Figure 3.2-3. Conversion of the zirconium liners completely to zirconium oxide gives weight gains of ~ 1460 and 1520 mg/dm2 for the crystal bar and the low oxygen sponge specimens, respectively. In comparison with the data shown in Table 3.21, it cen be seen that both types of barrier were completely oxidized in 36 days at 350 *C, whereas the 3 and 12 day tests resulted only in partial oxidation of the liners. The weight gain data are consistent with the results obtained from metallographic examination, Figures 3.2-3 and 3.2-4. One interesting feature observed in the photomicrographs shown in Figure 3.2-3 is that zirconium hydrides tended to concentrate at the vicinity of the interface between the zirconium liner and the Zircaloy.

The weight gain data, Figure 3.2 5, showed a linear relation with test duration for the 3 and 12 day tests. The reaction rate of the crystal bar liner is slightly higher than that of the low oxygen sponge liner. Extrapolations of both lines intercept the dashed line at 18.5 and 24.5 days for crystal bar and low oxygen sponge-based liner, respectively.The dashed line represents the weight gain of a com-pletely oxidized zirconium liner of 0.065 mm (0.00255 in.)in thickness. Since the weight gain data from the 36 day test are nearly the same as the value estimated to have reached af ter only 18.5 and 24.5 days for crystal bar and low oxygen sponge liners, respectively, it apoears that the corrosion reaction was stopped at the zirconium-Zircaloy interface, and no signifi at reaction occurred for 12-18 days af ter the complete oxidation of the barriers.

A4-32

z1$hs~ ye

• t' Sg9 Cg*o [u S4 ,

E 1 R

UE /,

SG SU EA RG \g P

E TE R L O P NV U EL T VA  ! A1 O C

V O  ?' F E O 2

H N M E R S G E T H E _

M )C T L -,

{'  :

L EA *8 =

E 8 C T

P S (2 T 2 .

O E r '

U R l s

R UK - u A

L TI PD SE t a

r U U a N R p N E p A C A I

NE t FI OV NT s

R I L e O A T l A L V r

. O t o

El S I l a

C *C ,

u A0 , r N56 i m

R( 3 U S C

F T d 2 l, _.! o

_ O R U d

l. 5 2 t

e C a E) T r C *C f o

A0 Y r e

N04 A R - l R P U00 - NT F 3 ISA 1 E( EN -

L LI 2 P , PM 3 M r MU e A ,

AL r S SA u g

E ,

'[

i N -

F O _

Z l M

E UE E UV R CL H AA T VV L

L I

F 1

=

K C

C^

EC A

- T RS B I

UD T

P E 2 U R E R U /,

SG .

SU EA R

P G

${w

1. LOW PRESSURE CENTRIFUGAL PUMP

2. F LOW M ETER

3. DE-lONIZER ( COVER GAS

4. CONDUCTIVITY METER

5. HIGH PRESSURE POSITIVE DISPLACEMENT PUMP

6. FILTER ' 9 U

7. THERMOCOUPLE

8. BLOWOUT RELIEF DISK . , _

4

" ~

9. ASHCROFT PRESSURE GAUGE '

10. BRISTOL PRESSURE RECORDER 13

=

11. NONREGENERATIVE HEAT EXCHANGER 3

12. BACK PRESSURE REGULATOR ' DOME FILL TANK

13. FLOW METER LOADING T J_.

14. REGENERATIVE HEAT EXCHANGER g GAS - ~.

d_

12

_g_ X 2 am a8 M '

9 10  ;- > ,o 11 CHILL WATER 1 5 N.

' L M O X

AUTOCLAVE M -

l 14 ---

7 6 8 5 T

Figure 3.2-2. The Refreshed Autoclave System .3hown Schematically

NEDO-24259-A (from CEAP-25163-2) if, u ' --

5 1

k ,e y}

I

• g- 3 l

~

% (

f ,

.. h ,

,A ,

' ej t/q 12 N'~

i DFC 1 -

1 .-y :

l ~ '

.;.. n ,T '

. s. . s: 4 xy.

l ,

s

2 -

, s- 2b , _ , .

500x Figure 3.2-3. Photomicrographs of (a) Low Oxygen Sponge and (b) Crystal Ber Zirconium Lined Tubing Before Testing, (1), and After Being Tested in the Simulator at 350*C in 7.0 MPa (1000 psig) Steam for 3 days (2).

A4-35

NEDO-24259-A

,, (from GEAP-25163-2)

Table 3.21 WEIGHT GAIN DATA OF SAMPLES TESTED IN THE SIMULATOR AT 350 AND 400*C

, Weight Gain, mg/dm2 Crystal bar Low Oxygen Temperature *C Duration, days Zircoloy 2 Only* Sponge Only*

352 2 3 3 7.9 276 20 192 2 56 356 2 6 12 14.7 963 48 750 89 354 2 4 36 19.3 1451 2 1486 54 407 7 3 --

894 57 877 2 3 403 2 2 12 26.1 1443 93 1556 2 0

• Average Of IWO SpeCirnens with range ind:Cated.

The weight gain data obtained at 400*C are shown in Table 3.2-1 and in Figure 3.2 5. Assuming that linear reaction kinetics exist also at 400*C, it is shown in Figure 3.2-5 that both liner types will be completely oxidized in ~ 5 days. In other words, the corrosion reaction at 400*C has also been stopped at the zirconium Zircaloy interface and no significant reaction occurs for 7 days af ter the complete oxidation of the liners.

The reaction rates are obtained from the slopes of the lines shown in Figure 3.2-5 and are tabulated as follows:

Material 350 *C, pm/ day 400'C, pm/ day Zircaloy-2 cladding 0.05 not measured Crystal bar zirconium 5.14 19.90 Low oxygen spor'ge zirconium 4.05 18.96 (B) Autoclave Test Corrosion tests in the refreshed autoclave system were carried out at 350 and 400*C in steam at a pressure of 7.0 MPa (1000 psig).

The corrosion weight gains for both types of barriers in 350*C steam for 3 days were only ~ 1/3 of those obtained in the simulation tests, Tables 3.2-2 and 3.2-3. Metallographic examinations showed no evidence of hydrogen up in the first three days at 350*C, Figure 3.2-6.

A 13 day test at 350*C showed that the crystal bar liner formed a white powdery oxide layer, while the low oxygen sponge liner remained essentially black, L 1 and X 1 in Figure 3.2 7(a). The weight gain data showed only slight increases from the 3 day test. Also at 400*C the corrosion rate of both liner types are significantly lower than those obtained from the simulation tests. A weight loss of 370 mg/dm2 was obtained for the crystal bar liner in the 400*C test because of the powdery nature of the oxide (samples hung vertically). The photomicrographs of the samples are shown in Figure 3.2-6.

A test was conducted at 350*C for 13 days to compare the effect of surface finish, e.g., as-grit blasted and light etched, one minute etched, and hand polished with sic paper (grade 600 grit). It was found that the one minute etching resulted in a corrosion rate of 18-30% less than the other two types of surface 1.ntments. The effect of surface finish is, however, only secondary as com-pared to the alfference between the liner types, Figure 3.2-7.

A4-36

1 NEDO-24259-A (from GEAP-25163-2) y m .?qg :- we ', g4 m . 4. ,. % . .

" 't _

h' R ,<F s ,g:$ :

y;Opf...'3i.; 3

. yg'3}g L iA Ig.

,, f -

.'y 3 s

9

~w

) lE.y tR ? *, . l ' ~ ,': ~ , r <;;.

qypy*l.l:Gi};ij'&"

4

,fsy'tpT;,-

4;ll@%;,f)' '

.[ ~(.

. ,  :. .k

^

- "?g A".' *

'?

Ql ' , ',d j];i4[t!2$ 0 D lj e i

, u. s, 2y 1

,S,!?A, *

• Y..

! , h *

g. ,

l 6

m1:**f f m,. &'

f 79l, ,

n<, t',

i- /

"Yihi/ n gag [N h.

i h*1 -

m*$.' ,

. 4 s 500X Figure 3.2-4. Photomicrographs of (1) Low Oxygen Sponge and (2) Crystal Bar Zirconium Lined Tubing After Being Tested in the Simulator at 350*C in 7.0 MPa (1000 psig) Steam for 12 days. (a) and (b) Repre-sent Different Locations of the Same Samples.

A4-37

3000 Os CRYSTAL BAR (CB)

O E LOW OXYGEN SPONGE (LOS) 2500 -

2000 -

n-E F

9 n

?, ,soo ___ D ___ _ _ ___ 8Em

>d 0 hf 400* C .1 yw b

00 c LOS 7b G CB N.

g 350'C $>

1000 -

LOS

[

CB Il 500 -

350 C ZlRCALOY - 2 RE FERENCE A ' ' ' '

0 f I _ O __

h-0 5 10 15 20 25 30 35 40 TEST DURATION (days) i Figure 3.2-5. Corrosion Weight Gains for Zr Liner Cladding and Reference Zircaloy-2 as a Function of Time at 350*C and 400*C in 7.0 MPa (1000 psig) Steam in the Simulator

fiEDO-24259-A (from GEAP-25163-2) '

Table 3.2 2 THE WElGHT GAIN (mg/dm') OF CLADDING SAMPLES TESTED IN THE RECIRCULATING AUTOCLAVE AT 350 AND 400'C Low Oxygen Temperature *C Duration, days Reference Crystal Bar Sponge 350 3 3.4 97 4 65 2 0 350 13 11.3 150 2 4 65 1 400 3 4.5 370 2 12 180 2 4 Table 3.2 3 WEIGHT GAIN (mg/dm') OF SAMPLES TESTED IN THE RE CIRCULATING AUTOCLAVE TEST CONDITIONS: 350*C,7.0 MPa (1000 psig),13 DAYS Hand Polished As received 1 Min Etched (#600 SIC)

Crystal Bar 150 4 103 2 6 142 2 3 Low oxygen sponge 65 1 52 2 5 61 1 Reference 11.3 The dif ference in corrosion performance of the zirconium liners in the simulator and the refreshed autoclave is believed to be due to the presence of hydrogen in the simulator. Tests of rirconium-based alloys in various laboratories have shown that higher corrosion rates can be expected if the tests are conducted in a small closed autoclave in which corrosion produced hydrogen can accumulate.'

3.2.1.1.4 Conclusions

1. The corrosion rates of zirconium liners in simulated defected rod conditions are significantly higher than those obtained in the refreshed autoclave. The accelerated reaction is attributed to the presence of significant amounts of hydrogen produced by the corrosion reaction.

2. The reaction rates obtained from the simulation tests at 350*C are 0.05 pm/d for Zircaloy 2,5.14 pm/d for the crystal bar liner, and 4.05 pm/d for the low oxygen sponge liner.

3. The corrosion react'on in the simulator at 350 and 400*C appears to have stopped at the zirconium-Zircaloy interface. No significant corrosion of the underlying Zircaloy have occurred for up to 36 days at 350*C and 12 days at 400 *C.

3.2.1.2 Characterization of Irradiated Zirconium Liners - (R. P. Tucker and R. B. Adamson, NFSED)

To characterize the zirconium liner materials, work is in progress to measure the relative microhardness of irradiated and unirradiated zirconium liners and Zircaloy cladding. A microhardness measurement plan has been carried out that provides a self-consistent and reliable data base for evaluating the effect of neutron fluence on the relative microhardness o' Zircaloy 2, crystal bar zirconium and low oxygen sponge zirconium. The testing was conducted primarily on one instrument by a single operator. Based on preliminary data using Knoop and diamond pyramid indenters and loads from 50 to 500 grams, the Knoop indenter and a 100 gram load were selected for generating reliable and di.ectly comparable myrohardness measurements for Zircaloy 2 tubing specimens with 0.076-mm thick zirconium liners.

A4-39

l NEDO-24259-A

) (from GEAP-25163-2)

! ?BBh ,

b .

l x ' -

N y 3 't

- ~

l '4

~

y j . l

'fp

'tr-

/ . 's.g,,

& ~'

' Ugw y < .  ;

g *< ,

) 4,

/ 9 h M*!;Q M. v ' , ./4 = ag 8

,I

' .[. ~' t i.

J.

3 r

2O y 2' soox Being stedin the Retre bed Autoc a e a 1)3

• an (2) 'Cl 70 MPa psi )S eam for 3 Days A4-40

NED0-24259-A (from GEAP-25163-2)

L1 L-4 L5 X-1 X-3

. man m

,,,, j illllIllll H illllll[Illl[Illllllll[ll H lH H [H H lH H [H Hl a

, Nf ]

jyn kf $f ,

gy - 7'3 %' 2

~

? '

. ,% ' h- L -0 ( i

. . ~

i

^

.. N ,\ i

^

. ' .Y'hh 'A ;j b d,,$ C j i, I

f. Y  ; 6{h

              ' i\                                                                                                                         $
           >                                                                                                                                  $. 1
                                ,.                     1         -                N       ,                             1      -
                                     ~
                                                   '^                                                                          '               '

l ., M* b

                                                                                                           )

P' w.

                                                                                                                       .J '

l , t.

            >                                                    L e                                                    Ii
                                                                             . J.A 500X Figure 3.2-7.          Photomacrographs and Photomicrograph:s of Specimens After Being Tested in the Reftashed Autoclave in Steam at 350*C, 7.0 MPa (t000 psig) for 13 days: (a) Inner Surface Visual Appearance; Specimens Labeled L have the Low Oxygen Sponge Zr Liner While Those Labeled X Have the Crystal Bar Zr Liner;(b) Crystal Bar Liner in the As-Received Condition;(c) Crystal Bar Liner in the Belt Ground Condition; Low Oxygen Sponge in (d) As Received;(e) 1 min Etched; (f) Belt Ground Conditions.

A4-41

NEDO-24259-A (fram GEAP-25163-2) The Knoop hardness numbers (KHN) reported here are the average values from a minimum of three hard-ness impressions made at a load of 100 grams. The tests were conducted at room temperature. As anticipated, the microhardness values for annealed, unirradiated materials were lowest for high purity crystal bar zirconium (KHN = 56 71), higher for low oxygen sponge zirconium (KHN = 118), and were highest for Zircaloy 2 (KHN = 173-185). Following neutron irradiation to fluences in the range 1.3 2.0 x 102' n/cm2 (E > 1 MeV), the microhard-ness measurements indicated hardening had occurred in all three materials, with Zircaloy 2 showing the greatest incret se. The relative hardness of these materials remained in the same order as existed prior to ir-radiation. For Zircaloy-2 irradiated in '.ne Segmented Rod Program (SRP), where the irradiation temperature was

  ~ 288'C, the hardness was in the range of 232 255 KHN. At higher Irradiation temperatures of 343*C (IMC-5 isothermal materials capsule irradiated in the GE Test Reactor) and 375'C (EBR-il1), the Kncop hardness numbers for Zircaloy 2 were 191201 and 220, respectively. The results indicate that irradiatica hardening is somewhat reduced at the higher irradiation temperatures.

The crystal bar zirconium from irradiated SRP rods exhibited Knoop hardness values in the range 81 107, whereas the low oxygen sponge zirconium irradiated in EBR-ll-1 at ~ 375'C measured 126 KHN. Figure 3.2-8 presents a visual comparison between the Knoop impression size for crystal bar zirconium liner and Zircaloy cladding in an irradiated sample. The results on crystal bar zirconium indicate that although neutron irradiation results in hardening, the microhardness remains well below that of unirradiated Zircaloy 2 for fluences up to ~ 2 x 102' n/cm2. Currently, the only microhardness measurements on irradiated low-oxygen sponge zirconium are en material irradiated in the EBR-ll at temperatures of 371'C and above. Since the effect of irradiation temperature on microhardness in this material remains to be documented, an Inference regarding the amount of hardening to be expected in sponge zirconium under BWR conditions cannot be drawn yet. However, the data show that sponge zirconium at a fluence of ~ 1.5 x 102' n/cm2 remains softer than unirradiated Zircaloy-2 and suggest that even at high fluence the sponge liner probably will not exceed the hardness of unitradiated Zircaloy 2. Figure 3.2-9 summarizes the Knoop microhardness results for Zircaloy-2 and zirconium liner materials as a function of fast neutron fluence. 3.2.1.3 Irradiation Hardening of Zirconium -(R. B. Adamson and G. H. Henderson, NFSED) Tensile tests have been conducted on irradiated zirconium sheets of two different purities. Crystal bar (200 ppm O) and sponge (800 ppm O) materlats were irradiated at 327'C to a fluence of 6.8 x 102o n/cm2 (E > 1 MeV) and tensile tested at 310'C. The sheet thickness was 1.27 mm (0.050 inches) and the specimen geometry was that previously described 4 for miniature unlaxial tensile specimens. Table 3.2-4 presents the data. It is seen that uniform elongation for both materials is low and the reduction in area is high. It is seen that the sponge material is significantly stronger than crystal bar material. Transmission electron microscopic characterization and optical metallography of these mateilats is in progress. 3.2.2 Subtask II.1.2 PCI Simulation Tests 3.2.2.1 Irradiations in the EBR il - (R. P. Tucker and R. B. Adamson, NFSED) Irradiation experiments are being conducted in the Experimental Breeder Reactor (EBR ll) to provide can-didate barrier Zircaloy 2 cladding with high fluence exposures for post-irradiation evaluations of these materials including their resistance to stress corrosion cracking under simulated PCI conditions, i.e., expanding mandrel tests. lrradiation has been completed on two series, each with four nonfueled tubing rods. The'se rods have been received at the Vallecitos Nuclear Center for measurement, sectioning, characterization and ter, ting. The materials in the first experiment (EBR fi 1) were:(1) reference (bright etched) Zircaloy-2,(2) copper on etched Zircaloy-2, (3) copper on autoclave-oxidized Zircaloy-2 and (4) 0.076-mm low-oxygen sponge zirconium-lined Zircaloy 2. The experimentally evaluated neutron fluences (E > 1 MeV) for rods (1) and (2) were 2.1 x 102 n/cm2 at core midplane (T = 410 *C) and 1.9 x 102 n/cm2 near the bottom of the core (T = 371'C) and for rods (3) and (4) the corresponding fluences were 1.8 x 102' n/cm2 and 1.4 x 102' n/cm2, respectively. The four rods have been sectioned and mandlel samples prepared for testing. Microhardness measurements have been obtained on selected sections from the sponge zirconium liner and Zircaloy 2, with additional measurements required to euluate the effect of irradiation temperature on microhardness. A4-42

NEDO-26259-A (from GEAP-25163-2)

                                                                               + 6('~C[,
                                                                                                                                   ?                                -
                                                                                                                                                                        ; .4 . ?7.         ,

4 4 /- Zr Liner

                                                                                                                                                          ~

Zircoloy-2

                                                                                                                                                                  +

25oX Figure 3.2-8. Comparison of Knoop Microhardness Impressions forIrradiated Crystal Bar Zirconium Liner and Zircaloy-2 Cladc!ng. (Fluence = 1.5 x 102' n/cm2 (E > 1 MeV), Irradiation Temperature

                                                                                                                      == 288'C).

Metallographic evaluations of the EBR-il 1 materials indicate:

1. Blistering and delamination of the copper liner on the autoclave-oxidized rod.

2. Corrosion and/or porosity of the copper liner on both the oxidized and etched rods.

3. Interdif fusion of copper with Zircaloy in the copper on etched rod with the dif fusion layer increasing in thickness with increasing irradiation temperature.

4. No macroscopic visual evidence of radiation effects on the sponge zirconium liner.

5. Hydrides, Indicative of ~ 100 ppm hydrogen in all rods with no evidence of increased hydrides at the zirconium liner / cladding interface. (The hydrogen concentration was determined by comparison with metallographic standards.)

Metallographic evaluations of unirradiated control specimens which simulate the thermal histcry of the EBR ll-1 experiment are consistent with the results on the companion irradiated specimens. The second series of rods (EBR-II-2) included the following materials: (1) reference (bright-etched) Zircaloy 2,(2) 0.076-mm low-oxygen sponge zirconium-lined Zircaloy 2,(3) 0.076-mm crystal bar zirconium-lined Zircaloy-2 and (4) copper on autoclave-oxidized Zircatoy 2. Irradiation to an estimated fluence (E > 1 MeV) of ~ 8 x 1021 n/cm2 at core midplane and ~4.5 x 102' n/cm2near the bottom of the core was completed in October 1979. A4-43

280 TEST LOAD = 100 grams e 240 - g g 326 C C

             ~

ZlRCALOY 2 ' h375C O 410*C O

             ~

343cC O E M: E - e p g 160 - oZ 2

   $                                                                LOW 4XYGEN SPONGC ZlRCONIUM                                                                                                  h o

140 - A y 3 Y o z , - - --- - 375oC g 410'C k$ i w d nw & 1 120& Y g we 4 w e 1 o 100 - m O O a [] $ 0 326 C e 6 343 C U 80 - CRYSTAL BAR ZlRCONIUM O O ZlRCALOY 2 60 ' A LOWCXYGEN SPONGE ZlRCONIUM 40 - O CRYSTAL BAR ZlRCONIUM IRRADIAT!ON TEMPERATURE = 288 C 20 - UNLESS OTHERWISE NOTED I  !  !  ! I  ! I  ! 0 0 2 4 6 8 10 12 14 16 18 20 FAST FLUENCE x 10 (nkm . E > 1 MeV) Figure 3.2-9. Knoop Microhardness vs. Fast Neutron Fluence for Zirconium and Zircaloy 2

NED0-24259-A (from GEAP-25163-2) Table 3.2 4 TENSILE TESTS OF ZlRCONIUM IRRADIATED AT 327'C TO FLUENCE 6.8 x 10 n/cm8 (E > 1 MeV) Unifum 0.2% Offset Ultimate Elongation Reduction Yield Strength Strength Total Elongation From Chart in Area Specimen MPs (ksi) MPa (ksi) (%) (%) (%) (.) Annealed 362.8 (52.6) 364.8 (52.9) 24.7 0.43 64.1 Zirconium Sponge 375.9 (54.5) 378.6 (54.9) 31.3 0.53 73.0 Annealed 257.9 (37.4) 257.9 (37.4) 25.3 0.20 76.4 Crystal Bar Zirconium 216.6 (31.4) 233.1 (33.8) 22.3 0.89 71.0 261.4 (37.9) 261.4 (37.9) 24.0 0.20 65.7

• Final thickness measurement la accurate. Final width was hard to measure accurately because the fracture tapered to a knife. edge. The

   " reduction in area" values reported are minimum values.

These rods are currently belrg sectioned to obtain expanding mandrel specimens, flux monitors and metallographic/microhardness specimens. Irradiation of a third series of rods (EBR-II 3) began in December 1979 and is scheduled for completion in August 1980. The projected fluence (E > 1 MeV)is ~ 4.2 x 1022 n/cm2 at core midplane and ~ 3.8 x 102 n/cm2 at the bottom of the core. The materials in EBR-II-3 are:(1) reference (bright-etched) Zircaloy 2,(2)0.076-mm low-cxygen sponge zirconium-lined Zircaloy-2,(3) 0.076-mm low-oxygen sponge zirconium-lined Zircaloy-2 heat treated to recrystallize the liner and to stress telleve the cladding and (4) thin (~ 0.03-mm) low-oxygen sponge zirconium-lined Zircaloy 2. The special heat treatment of material with 60-70% cold work (item 3) was a four hour isother. mal anneal at 480'C. The thin zirconium liner (item 4) was prepared by coating the outside and end surfaces of the tube with lacquer to prevent chemical attack and then immersing the tube for short times in a bath of 45% HNO3 (conc),2% HF and 53% H2O to reduce the liner thickness.This rod will provide irradiated material for the evaluation of the effect of liner thickness on the resistance to failure under simulated PCI conditions. i 3.2.2.2 Expanding Mandrel Tests -(S. B. Wisner, G. H. Henderson and R. B. Adamson, NFSED) To simulate the behavior of high fluence and high activity ;> 100 R!hr) Zircaloy cladding under PCI stress conditions and environment, a fully remote expanding mandrel 'oading system (REMLS) has been designed and Installed in a remote handling cell at General Electric's Vallectos Nuclear Center. The in-cell expanding mandrel test is similar to the out of-cell test except for some special equipment that was redesigned or modified for remote use. Figure 3.210 is a photograph of the REMLS and shows the special equipment. In the lef t foreground is a spotwelder which positions and welds a chromel-alumel thermocouple on-to the outer surface at the midline of the specimen. This thermocouple is used to monitor the specimen temperature and for thermal control. The extensometer positioner is a vehicle that moves oa, tracks and pre-cisely positions an extensometer around the specimen midplane diameter.The extensometer gives the average diametral extension during a test. Also seen in the figure at the right side is the remote handling " slave." There are two slaves, lef t and right, with extensive x-y-z linear motion and 360' rotary capability at the gripping Jaws. The REMLS is now fully operetional, and simulated PCI tests on specimens irradiated in the EBR-ll-1 and EBR-11-2 experiments are now in progress. A4-45

' NEDO-24259-A j (from GFAP-25163-2) t P00R ORIGINAL

                                                                                                                                                             .         .,a REMOTE HANDLING                                     . ;. /

4 _ g; . _ SLAVE , [ fi . i y' ,. .. ,. F" g.. .

                                                                                                     . L'JI'                        . , - .
                                                                                                                                                                / / ,, '
                                                                                                                                                                  >u
                         .         er                                                                                                                                      'O 4                                                                                                                                      >
                                                       ~

4'* e' gee 3 -P. - N .. , 4- . m h o w e $ e t>4 9 ' #

                                                                                                                                                      . + , .                -:
                                                                 . 7                                               :

M l . m * <

                .'z                                          -

as .._

                                                                                                                                                  .W
                                                  ..         2             .s                      .

l Figure 3.210. Remote Expanding Mandrel Loading System (REMLS) A4-46 f

i NEDO-24259-A (from GEAP-25163-2) j ACKNOWLEDGEMENTS The co7tributing authors of Subsection 3.2 gratefully acknowledge the in<stuable assistance of: R. E. Blood and R. D. Jones of NFSED in the preparation and shipping of rods for the EBR-Il experiments. 4 ! R. E. Smith, D. L Orton and R. D. Sanchez of the Irradiation Processing Operation for hot cell metallography and microhardness measurements. G. C. Martin, R. D. Reager and D. M Simpson of NFSED for fluence determinations on rods irre.3%ted at l. the EBR-il. G. R. Lundeen and D. Pereyra of NFSED for metallographic support. 4 W. L. Denison, M. A. Bell, G. E. Dunning and W. E. Maki of Nuclear Power Systems Engineering Depart-ment for fabrication and characterization of rods for the EBR-il experiments. ] l 4 A4-47

NEDO-24259-A (from GEAP-25163-2) 3.3 SUBTASK 11.2 LICENSING TESTS 3.3.1 Loss of Coolant Accident Simulation - (M. B. Reynolds, R. E. Blood, r.. D. Jones, NFSED) 3.3.1.1 Introduction An experimental program designed to compare, under simulated loss of coolant accident (LOCA) condi-tions, the behavior of reference Zircaloy cladding and various types of barrier cladding has been carried out and reported earlier.:In those experiments a segment of cladding tubing containing depleted UO, pellets was sur-rounded by saturated steam at atmospheric pressure and heated electrically at rates postulated for a LOCA event. Fission gas pressure loading on the tube test segment was simulated by pressurizing with argon. Tests were carried out at fixed argon pressures corresponding to hoop stresses of 3.45,5.17 and 6.90 MPa. Tube f ailures were not observed at the lowest (3.45 MPa) hocp stress level within the heating times used (6.2 minutes). The present series of exoeriments was carried out to supplement the earlier work. 3.3.t2 Experimental Details A. Test Material The following materials were used in these tests:

1) Bright reference Zircaloy 2 (unlined) tubing

2) Low oxygen sponge Zirconium-lined tubing

3) Crystal bar, Zirconium-lined tubing Each of these materials were in the fully recrystalized (anneaied) condition.

B. Test Procedures The test specimens, filled with pellets of depleted uranium oxide, were electrically heated in saurated steam at atmospheric pressuro in a Vycor chamber. Details of test configuration, in-cluding thermocouple placement between the pellets were described previously.8 The UO, pellets are distributed approximately symmetrically about the thermocouple junctions at the specimen midplane although the thermocouple leads and insulation in the upper half of the specimen somewhat alter this symmetry with respect to thermal capacity. The test specimen was resistively heated by passing current from a phase controlled ignitron low-voltage power supply through it. The" control thermocouple"in the center of the specimen was con-nected to a closed loop temperature controller driving the firing control network of the ignitron po ser supply. The specimen heating schedule was determined by a temperature programmer. The temperature-time program used in this series of tests was that used in the previously reported test and is illustrated in Figure 3.3-1. Specimen rupture was indicated by an abrupt drop in pressure !n the specimen. Pressure within the specimen was indicated by a strain gage type transducer. Data from the specimen thermocouple, optical pyrometer and pressure transducer were collected and stored during the course of a test by a computer system, converted to temperature or pressure and plotted as functions of time by an X-Y plotter. Two of the four irmut channels of the computer preamplifier were connected to the chromel-alumel thermocouple between the pellets at the midplane of the specimen, a third channel was connected to the pressure transducer, and the A4-48 l l

M8,M Nuf> a*S 0e/ N$ $tN" Guw < @S-0 0 0 0 0 0 0 0 0 0 0 0 2 1 1 1 0 1 9 0 8 = 0 4 W 2 1 0

                   -     -     -              -       ~    -  -  -    -       8

_ - - 4

                                               \
                                           \
                                  \
                         \ \
         \
                 \{\

0

                                                                          !    2 4

0 6 E E 3 T T g AA n MR i t I X G s OIN e T RL PO A PO C AC 0 0 O 3 L d t e l a

                                                                                     )     u c    m e

s i ( S E r 0 o 4 M I f 2 T e nr i T f o n i o t 0 8 c n 1 u F a s a e r t u 0 a r 2 e 1 p m e T _ 1 _ 3 - 0 3 6 e r u g o F 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 m O 0 8 0 6 0 4 0 2 4 2 0 8 6 4 2 2 2 1 1 1 1 i CGW <5S-R*

NED0-24259-A (from GEAP-25163-2) fourth channel to the optical pyrometer. The coinputer was programmed to sweep all four channels every two seconds until a total of 1200 readings (300 per channel) were collected. The total sample collection time of 600 seconds was chosen to match the program drum rotation rate of the temperabre programmer, A temperature / pressure versus time plot from a typical test is shown in Figure 3.3-2. 3.3.1.3 Test Results A series of specimens were tested - two or three from each of three tubing types at each of two hoop stress levels. The temperature and strain data from these tests are summarized in Table 3.3-1. The barrier tubes and the reference tubes did not differ significantly in behavior under the simulated LOCA conditions of this test series so far as rupture temperature and time to rupture were concerned. Circuinferential fracture strain was somewhat higher for the Zirconium-lined tubes than for the unlined Zircaloy tubes. Photographs of ruptured tubes are shown in Figures 3.3-3 and 3.3-4.Without measured values of surface temperature at the point of rup-ture it is not possible to relate rupture strains accurately to temperature. It is a characteristic of the test apparatus for the temperature of the lower end of the specimen to lead the temperature at the specimen midplane by as much as one hundred degrees Celsius

• during the heating phase of the test. Consequently, failures occur in the lower, hotter portion of the specimen. In order that present test results be consistent with previously reported results, no effort was made to change this behavior by modifica-tion of the test configuration or test procedure used earlier 8. All reported rupture temperatures obtained with this apparatus are low by about ~100*C. Previously reported rupture temperatures are the average of midplane pellet and cladding surface temperatures - neither of which represents the visually obviously higi:ar temperatures at the point of rupture. In Table 3.3-1 pellet temperature and the midplane cladding surface temperature are reported.

Strain values are based on mean of major and minor diameter measured at point of rupture and at specimen midplane where surface temperature was measured. Results of these measurements are given in Table 3.31.

   ' Visual estimate based on color differences. The optical pyrometer focuses on the specimen at midplane.

A4-50 L

2m8iw1- bee i mQo3 0m>J" buWmW wv

                =g $5w$a                                                                           _

0 0 0 0 0 0 ' _ 5 0 5 0 5 0 0 - 3 3 2 2 1 5 0 1 0 _ _ 1

                                                        ^
                                                        ^                            9

_ l 0

                                                        'f 8

z } 0

                                                         ^

rE R T L 7 0 t E ^ - E s e L M _ P O T U R O - Y _ A C C P O , _ O L M . 6 R . l r E 0 f o H .

                                                                                        )    t T                                   _

D u E p _ Z t l l u

                                                                            .           A   O M     r 5        e L              R    t u

0 O p N ( _ m E o i M I C T l a c [d ^ l 4 0 i T p y i - 2 - _ in 3 Nm A 3 P 0 e S (1 3 r u Es l 0 g M0 I 0 i F T6  : E - 2 R _ 1 0 U' - S S _ E

                               .                                _    E R- .                                             L P

P- _ R , U E O C T _ O E 1 _ M M l 0 _

                               ,                     O          _    R                             _
                                                                . E R

Y , H _ T P T

     -  -     -          =-                        -               -                  0 0  0  0     0                   0              0                 0           O 0 0  0  0     0                   0              0                 0 5  0  5     0                   5              0                 5 3 3  2     2                   1               1 E* w:ahfwgwe i
                                   >tiv

[

j NEDO-24259-A i (from GEAP-25163-2) P00R ORIG NAL 6 REFERENCE ZlRCALOY I _ . . - - - ~ * - ---

                                                                                                                                                   $PONGE LINED l

CRYSTAL BAR LINED 1 cm l l Figuro 3.3-3. LOCA Specimens Tested at 5.2 MPa Hoop Stress Original Tubing Outer Diameter = 12.3 mm A4-52

NED0-24259-A (from GEAP-25163-2) I U U 51 U313Ull] l l ! j REFERENCE ZlRCAsf I

                       +

SPONGE LINED ( ,

• CRYSTAL BAR LINED 1cm l Figure 3.3-4. LOCA Specimens Tested at 6.9 MPa Hoop Stress A4-53 l

NEDO-24259-A (from CEAP-25163-2) , t .' ; ! Table 3.31 LOCA TEST

SUMMARY

Hoop Failure Rupture Temperature 'C (*F) Stress Time, Specimen Tspe Center Surface

• MPa (PSI) CFE,% CUE,* % Minutes A-1 922 (1817) 100G (1846) 5.17 (750) 55 8.3 4.75 A.1 978 (1792) 1008 (1846) 5.17 (750) 71 8.3 4.9 A.2 918 (1685) 971 (1779) 6.90 (1000) 112 7.5 4.5 A.2 907 (1665) 981 (1798) 6.90 (1000) 130 5.1 4.3 S-1 971 (1760) 1016 (1860) 5.17 (750) 107 13.9 4.7 S.1 984 (1803) 1006 (1842) 5.17 (750) 98 8.0 5.3 S.2 777 (1430) 916 (1680) 6.90 (1000) 132 1.74 3.45 S2 919 (1687) 967 (1773) 8.90 (1000) 124 4.0 4.3 S.2 907 (1664) -

6.90 (1000) 126 4.7 4.0 X.1 967 (1772) 996 (1825) 5.17 (750) 99 9.4 4.5 X.1 971 (1780) 1049 (1920) 5.17 (750) 67 6.5 4.6 X-2 921 (1690) 1199 (2190) 6.is0 (1000) 129 6.4 4.3 X.2 909 (1668) 964 (1767) 6.90 (1000) 127 4.7 4.0 X2 926 (1699)  % 2 (1764) 6.90 (1000) 136 5.6 4.2 A - Bright etched. annealed 2 - 6.90 MPa S - Low oxygen sponge zirconium leed CFE - Circumferential fracture elongation X - Crystal bar zircomum lined CUE - Circumferential uniform elongation 1 - 5.17 MPa *

                                                                        - Meascred at specimen midplane 3.4 SUBTASK l1.3 FUEL IRRAD'ATION TESTS 3.4.1     Segmented Rod Irradiation Tests (J. H. Davies, E. Rosicky, D. K. Dent'ison and E. L. Esch, NFSED) 3.4.1.1     Bendle Status The irradiation status of the three segmented test rod (STR) assemblies in the segmented rod program (SRP)is updated in Table 3.41. No bundle reconstitutions were performed during the current reporting period.

3.4.1.2 Power Ramp Tests 3.4.1.2.1 Imroduction Following the successful ramp testing of 12 GE fuel rods performed in 1978 in the R2 Reactor at Studsvik8 ', a larger program was defined for testing in 1979. Thirty.six fuel rods segments were selected from segmented rod assemblies in both the Monticello (SRP 2) and the Millstone (SRP-3) power reactors and carefully characterized in the Hotcells of the GE Vallecitos Nuclear Center. This included visual examination, pro-filometry, gamma scanning, neutron radiography and pulsed eddy current testing. The rods were shipped to Studsvik in July and ramp tested during the Fall.They included 14 reference f uet rods,6 Zr. liner and 16 Cu-barrier fuel rods. The test program had four main objectives:

1. Investigation of the need for an extended low power standardization period prior to ramp testing. i l

A4-54 e

NED0-24259-A (from CEAP-25163-2) The 300-hour standardization irradiation, which was used in the 1978 R2 test series, was a somewhat arbitrary requirement, included to preserve test parity with earlier tests at the GE Test Reactor (GETR). This phase of the test was time-consuming and expensive and perhaps unnecessary.

2. Testing the PCI resistance of Cu-barrier fuel at lead exposures.

3. Testing the ability of Zr liner and Cu-barrier fuel to survive a large power step at low to medium exposures.

This test was a closer simulation of a control blade withdrawal than the standard " staircase" ramp test.

4. Investigation of performance limits of Cu barrier fuel.

Failure of two Cu-barrier rods with a thin (5 pm) layer of copper in the 1978 test series, af ter univer-sally good performance at lower exposures, indicated a possible exposure-dependent loss of pro-tectiveness of the Cu-barrier. A small test matrix was set uo to explore the effects of residual copper layer thickness and exposure. 3.4.1.2.2 Test Description The R2 Test Reactor faci!ities have been described previously8 . The 36 fuel rods selected for ramp testing are described in detail in Table 3.4 2. As before, reference rods were defined broadly as thos. rods with un-modified Zircaloy cladding, although there were differences among references in conventional design features (cladding wall thickness, diametral gap, helium pressure). Table 3.41 SRP IRRADIATION STATUS Highest SRP Average Segment Exposure Average Exp;,. ore STR Bundle Segment Tier (MWdikg U) (MWdikg U) Date SRP1 Top 12.5 14.7 November 30,1979 (Quad Cities.1) Mid Top 18.2 21.5 Mid-Bottom 18.2 22.3 Bottom 14.7 18.5 Bundle Average 15.9 SRP-2 Top 13.8 18.2 December 31,1979 (Monticello) Mid Top 21.4 27.8 Mid-Bottom 23.9 30.9 Bottom 20.8 27.0 Bundle Average 20.0 SRP-3 Top 12.9 17.4 December 31,1979 (Millstone) Mid Top 19.5 23.7 Mid-Bottom 22.1 25.3 Bottom 19.8 22.5 Bundle Average 18.6 A4-55

WEDO-24259-A (from GEAP-25163-2) Table 3.4 2 DESCRIPTION OF FUEL RODS RAMP TESTED IN 1979 Seg. ment Cladding Diametral He Ave. Identifi- Wall Gap Pressure Burnup* Test cation Design Feature'**l (mm) (mm) (MPa) (MWdIkg U) Objective'* SRP 217 Reference 0.86 0.18 0.1 15.9 1 SRP-2/8 Reference 0.86 0.18 0.1 14.9 SRP 2/9 Reference 0.86 0.23 0.1 13.8 SRP-2/16 Reference 0.86 0.23 0.1 15.b SRP 2/25 Reference 0.71 0.18 2.2 18.1 SRP-2/26 Reference 0.86 0.23 0.1 20.4 0.23 0.1 19.2 1 SRP-2/27 Reference 0.86 SRP 2/2s 10 pm Cu-barrier (nonbonded) 0.86 0.23 0.1 13.1 2 SRP-2/29 10 pm Cu. barrier (nonbonded) 0.86 0.23 0.1 15.2 SRP-2/30 10 pm Cu-barrier (nonbonded) 0.86 0.23 0.1 13.0 SRP 240 10 pm Cu-barrier (electro!ess) 0.86 0.23 0.3 6.3 SRP-2/12 Reference 0.86 0.23 0.1 12.4 3 SRP-2/15 Reference 0.86 0.23 0.1 16.4 SRP 2/21 Reference 0.86 0.23 0.1 10.4 SRP-2/22 Reference 0.86 0.23 0.1 15.9 SRP-2/24 Reference 0.71 0.18 2.2 19.4 SRP-3/7 Reference 0.71 0.23 1.7 3.6 SRP-3/29 High OlU Fuel

• 0.71 0.23 1.7 9.0 SRP-2/2 10 pm Cu-barrier (nonbonded) 0.86 0.23 0.1 10.5 SRP-2/31 10 pm Cu-barrier (nonbonded) 0.86 0.23 0.1 8.1 -

SRP-2/32 10 pm Cu-barrier (on-oxide) 0.86 0.23 0.3 4.8 5 pm Cu-barrier (nonbonded) 0.71 0.23 1.7 5.6 SRP-3/16 SRP-3/41 10 pm Cu-barrier (electroless) 0.86 0.23 0.3 6.2 5 pm Cu titrrier (electroless) 0.86 0.23 0.3 5.7 SRPC!42 76 pm 2.r. liner (sponge) 0.86 0.23 0.3 4.8 SRP-2/34 76 pm Zr liner (crystal bar) 0.71 0.23 1.7 5.6 SRP-3/20 76 pm Zr liner (crystal bar) 0.71 0.23 1.7 5.9 SRP 3/44 76 pm Zr-liner (crystal bar) 0.71 0.23 1.7 5.7 SRP-3/45 76 pm Zr liner (crystal bar) 0.71 0.23 1.7 7.4 SRP-3/46 4 76 pm Zr liner (crystal bar) 0.71 0.23 1.7 7.0 SRP-3/47 0.71 0.23 1.7 9.6 4 SRP-3/24 10 pm Cu barrier (bonded) 10 pm Cu-barrier (bonded) 0.71 0.23 1.7 9.3 SRP-3/25 5 pm Cu barrier (bonded) 0.71 0.23 1.7 10.9 SRP-3/31 5 pm Cu-barrier (bonded) 0.71 0.23 1.7 10.5 SRP 3/32 10 pm Cu barrier (bonded) 0.71 0.23 1.7 15.5 SRP 3/38 1 10 pm Cu barrier (bonded) 0.71 0.23 1.7 15.0 SRP 3/39 NOTES a) All cladding is Zircaloy 2 (recrystallization anneal); fuel density,95.5%. ty C6 bamers are a:1 electroplated except for Cu (onexide) and where stated to the contrary. Bonded barrier means plated tubes subjected to a diffusion anneal durin0 abrication f to form Co.Zr intermetallic layer. c) Bumuos calculated from "'Cs g mma scans by comparison to known standards. d) See introduction for definition of Objectives. Objective 1,2. 4 rods - Ramp Sequence A. Objective 3 - Ramp Sequence B. e) Fuel OlU rat 6o in range 2,02 2.07. 4 A4-56

HEDO-24259-A (from CEAP-25163-2) Table 3.4 2 also indicates the Test Objective for each rod. For Objectives 1,2 and 4, a "sta'rcase" ramp sequence was employed similar to that used previously.This was labeled Ramp Sequence A and is depicted in Figure 3.41. The big step ramp to meet Objective 3 was labeled Ramp Sequence B and is shown in Figure 3.4 2. Note that Sequence A standardization is at 9 kW/f t (29.5 kW/m), slightly higher than the nominal level,8 kWlf t (26.2 kW/m), employed previously. This change was necessary, because the six hour standardization had to be performed in the ramp test rig in R2 with the reactor at full power, and it was not possible to guarantee the specified maximum peak power of 18 kWlf t (59.0 kW/m) using the 8He coil alone, if the standardization power was less than half the maximum. In Ramp Sequence B the specified power shock was from 8 to 16 kWlf t (20.2 to 52.5 kW/m) the f actor of 2 power increase being within the capacity of the 8He device. If a rod survived this test,it cas given an additional small power shock, not exceeding 2 kWlf t (6.6 kW/m), using any residual capacity still Evallable in the 8He coil (see Figure 3.4 2). Rod f ailures were recognized by steep increases in the loop activity level, but additional evidence was col-lected to show that this burst of activity of ten lags considerably behind actual rod defection in several tests the tctivity burst was preceded by the small " power" ; pike noted previously.8 8 In one case (Figure 3.4-3) the spike coincided (allowing for the appropriate delay time) with a small, but discernible activity increase, supporting the hypothesis that the spikes are early (probably virtually instantaneous) indications of rod defection and large ac-tivity releases are delayed until pressure equilibrium has been established across the defect and/or small pressure transients or power ripples promote an aspiration effect. Forsyth et al.' have reported that pressure changes of about 1 bar will produce such bursts of activity and they have also shown that small PCI defects may virtually reseal themselves. The " power" spikes are not a general observation and the phenomenology of the ef-fect remains to be defined. Following a certified rod f ailura, power was rapidly reduced by pressurizing the 8He coll. Shortly thereaf ter the rod was raised from the core and, af ter an appropriate cooling period, it was removed from the rig. All the rods will be visually examined in the Studsvik hotcells and neutron radiographed prior to shipment back to the GE Vallecitos Nuclear Center for a more detailed examination. 3.4.1.2.3 Results and Discussion Preliminary results of the ramp tests are summarized in Table 3.4-3. The results of the first seven tests, cddressing Objective 1, are compared with prior Reference rod results in Figure 3.4-4. The premature failure of SRP-2/26 during the standardization period at 9 kWilt (^9.8 kW/m) was inconsistent with other Test Reactor Ramp test results reported in the literature, but not inconsistent with the low probability failure threshold observed in some power reactor experience 8. This rod will be examined closely in the post-irradiation examina-tion phase of the work. Because SRP-2/26 f ailed curing the low power standardization step, the results could not be included in the evaluation of the effect of standardization time on ramp test failure power. From the remain-Ing results in Figure 3.4-4 it was judged that there was not a significant difference in failure propensity between rods standardized for six hours and 300 hours respectively. All %bsequent tests were performed using the six-hour period. Three of the four Cu-barrier rods, ramped to test the PCI resistance of Cu-barrier fuel at lead exposures, survived. However, the highest burnup rod, SRP-2/29, failed, albeit at the maximum peak power of 58 kW/m (17.7 kWitt). This result was consistent with prior experience, which indicated that the ef fectiveness of the Cu-barrier as a PCI remedy appears to decrease at burnups around 15 mwd /kg U. The total ramp test experience with Cu-barrier fuel is shown in Figure 3.4 5. A literature representation of power reactor fuel performance 8 is in-cluded for comparison. It is believed that the " wear-out" ef fect is due to the slow interdif f usion of copper and zir-conium forming a brittle intermetallic layer. This problem, which was anticipated, led to the development of a process for plating copper on autoclave oxidized cladding, where the oxide film acts as a dif f usion barrier to pre-vent copper zirconium interdif fusion. Rods of this design, to be tested at the appropriate burnups, are being ir-radiated in the SRP bundles. A4-57

i 6 ' ' ' zM wen

                       -QoUO$m[ ~ yN" A

e c 6 n 1 e u O q e G t s e T p l m m a S

                                             /

W R k R e U 6 s O 6 a H ( h t P 6 f

                                             /     W                                  n WO                                       o k H                                     t i

2 1 a

                                               =-

P t z I 1 dr AA 1 a d C n t a I 0 ) S 1 h ( ) P s A E r N u O MI o I T T I 9 H AI 6( T I t N r m I o T h I 8 S S E f T o N t c O e

                                       ,                     E             I 7      f f

S I E _ R e _ t R a E g W I 6 i t O s

                                                       ?     P                          e P                          v E                         I n

S T R S t o U e O c H n 6 e u q

                                                       <                               S e

O t s e T p m a R

-  -    -   -   -    -        -      -               -     -    -       -               1 4  2     0  8    6    4       2       0               8    6     4       2    ,          4 2  2     2  1    1    1       1       1 3

e r u _kr*E$ w5a. i g F ~ - - - - - - - _ 0 7 0 8 W " # 0 2 0 1 _Ead E$b w5a.

                                >e&co

Zm3 w u $>

                                         ^' O3 a    L$@YNv                             _

5 1 4 1 3 1 M U 2 M I 1 X A M

       )

m S

       /

R 1 W k U 1 6 O H 6 ( 6 t f

       /

W  ! o k t 2

        =

P A 9 f P6 B e lh c ( n t E e

                <                     f
                                      /

MI u q W k 8 T e

                =                     6                                          S 1                                          t pO                                              s T
                                                     ,                            e S                                                                T R                     8                                           p U                                                          7 O                                                                 m H                                                                 a 2                                                                R N

EI O 2 t ST 4 I A RI 6 T 3 E IRD

• Y_ RI EN e

r G UO _ WI u g N OI A R O P S T i R H E _ E F R0 0P S P T E E3N R O U O _ ' N SO W (MTI O H PRA 6 E EZ L TID BG AN R _ TO A D P E L N O CR COT AFS A yI 8 1 6 1 4 1 2 1 o t 8 6 4 2 0 2{ e* (E 0 6 o S 0 4 0 3 " o j 0 ygc gwha. yE

                                               >I *

                   . .                             .- -                                        .                                       -                   .~ . _ _ . _              .

.~: , l~ i l- [ , j  ;  ! - _.

                                                                                                                                                                          .e l                                                                                             .__.
                                                                                                                                                                               ......4._.
                                                                                                                                                                                                                                    ,                                                             .       " SPI K E**

g  ; a 4 a s t

• t i ,

p

                                         -                                                                                                                                                                                                                                                                                           s i

POWER 53.2 kW/m 06.2 kW/f t) .

                                                            #e_                                                 , . p. 7                                 .

t f. j i i. .

                                    +-                               a                                                                                                                                                              [                         .                                                                                      t
                                                                                                                                                                                               ..' l _.                            *

{ g- s , ,. . l'

                                                                                                                                                                                                                                                                                                                                                       'g 1                        i                               1                                                                                    i                                                            6
                                                                                                                                 - 'l                                                                                                                                                           :
                                                 -s          .                   -

1 -

                                                                                                              .'; ) .-                                                   ;       .                  p                              ,                          ,-                                ,
                                                                                                                                          *                                                                                       .                           i                                 ,

N , I: g

                                                                                                                                                                         +                                                                                                                                  ACTIVITY INCREASE                             1
                                                                  -{

a l , l

                ...'.,;             l

i l

l..--. I t

                                                                                                                                                                                                                                                                                                                                                                                  ^

p

                                    .                                                       *--s                                                                                                   .

oz t f U rn

                                                                                                          ..*' + -s.--_

t-g y g- , . 7 ^ i- M ' " ' I * * "* }* ~ \ 'f,'*

> ' ACTIVITY t . .I. ~" '..._%4_#. * -

f

                         '~'                                           '

i, , 5 i i _T_, hN m t-4 o '? (vi 3 N b$ l e- we I' '

                  -:                                                                                                               e                                                                                                                   -- , ---
                                       .o-
                                                                                                          . I

__,9 _.. j  !,..> - g- - g4

                                                                                                                                                                    ; t co-c+                                            .-                                          o
                                                                                                                                                                                                                                                                                                                                                                ,m                u m

p . ._ .. , . [ - I 1 ,, _ _ . _ . _. .. - ., y 4 ... . . g

        ._._._..._.g.                                                                   . . . . _ . _ . _ .        .. .               ...._._..                         2...     . .. ..                                       .
                                                                                                                                                                                                                                                                                   ._.;                                         26.2 kW/m (8 kW/f t) l.-.           -

l I i i

                                             .__.._                                 - . . .                                                          .                                 -                                       e                                                              l                         ,
                                         .         .            .                  . . .                                                                                                                     ..                i
                                   -j                                                                                .                                                  I
                                                                                                                                         ;                              !                         '                                                       ,                                  i I                                                                                  '                          ;                                                                                                                                                                  '

t j 1 i  :

                                                                   ' (, ~ ~ ' - ~ .
                                    ..                                                                                                   l                              .                          I                                                      i                                  .
                                                 .,                                                                                      .                              I                         e                                                                                         t l                                                          l                                                                                                                  i 4

8 -- --

                                                   .                                                                                     .                              i I

i. i . -

I . a s l t ' I

                                   .i              . . . _ . . .          _._...._i                                                      j.

l__.. i - e  ! i j l

• I

2 mW/cm t

Figure 3.44. Reca. der Chart Output, SRP2/21 i i r i

NED0-24259-A (from CEAP-25163-2) Table 3.4 3 1979 SRP RAMP TEST, PROGRAM RESULT

SUMMARY

Averago Maximum Time to Rod Exposure Peak Power Failurew Rod identification Design mwd /kg U kW/m kW/ft (minutes) Result Remarks SRP-2/7 Reference 15.9 46.2 14.1 45 Failed SRP 2/8 Reference 14.9 46.5 14.2 50 Failed SRP-2/9 Reference 13.8 46.0 14.0 15 Failed SRP-2/16 Reference 15.8 52.6 16.0 0.5 Failed SRP-2/25 Reference 18.1 52.3 16.0 6.5 Failed SRP-2/26 Reference 20.4 29.8 9.1 26 Failed SRP 2/27 Reference 19.2 39.4 12.0 41 Failed Power Spike (11 minym SRP 2/28 Cu-barrier 13.1 58.8 17.9 - Sound SRP 2/29 Cu-barrier 15.2 58.0 17.7 147 Failed Power Spike (44 minym SRP 2/30 Cu-barrier 13.0 59.0 18.0 - Sound SRP-3/40 Cu barrier 6.3 58.7 17.9 - Sound SRP-2/12 Reference 12.4 53.2 16.2 50 Failed SRP-2/15 Reference 16.4 50.5 15.4 23 (75)'c' Failed Power Spike (15 minym SRP-2/21 Reference 10.4 53.2 16.2 2.5* Failed Power Spike (2 minym 4 SRP-2/22 Reference 15.9 52.1 15.9 40 Failed SRP 2/24 Reference 19.4 52.1 15.9 4.5 Feiled SRP-3/7 Reference 3.6 59.1 18.0 - Sound SR P-3.29 High O/U Fuel 9.0 58.7 17.9 - Sound SRP 2/2 Cu-barrier 10.5 58.6 17.9 - Sound SRP-2/31 Cu-barrier 8.1 59.0 18.0 - Sound SRP 2/32 Cu-barrier 4.8 59.0 18.0 - Sound SRP-3/16 Cu barrier 5.6 59.3 18.1 - Sound SRP-3/41 Cu-barrier 6.2 59.0 18.0 - Sound SRP-3/42 Cu barrier 5.7 58.8 17.9 - Sound SRP 2/34 Zr-liner 4.8 59.0 18.0 - Sound SRP-3/20 Zr. liner 5.6 59.4 18.1 - Sound SRP-3/44 Zr liner 5.9 59.3 18.1 - Sound SRP-3/45 Zr liner 5.7 58.5 17.8 - Sound SRP-3/46 Zr liner 7.4 58.8 17.9 - Sound SRP-3/47 Zr. liner 7.0 59.1 18.0 - Sound SRP-3/24 Bonded Cu barrier 9.6 52.5 16.0 28 Failed SRP-3/25 Bonded Cu-barrier 9.3 58.2 17.8 30 Failed SRP-3/31 Bonded Cu barrier 10.9 52.2 15.9 55 Failed SRP 3/32 Bonded Cu-barrier 10.5 52 ? 16.1 34 Failed SRP-3/38 Bonded Cu-barrier 15.5 ~ 52.3 16.0 21 Failed SRP-3/39 Bonded Cu barrier 15.0 52.6 16.0 9 Failed (O Failure times based on loop actmty level. Minutes to failure from end of last ramp step. (b) See discussion 6n text and Figure 3 4-3. Time in parenthesss 63 the time from end of last ramp step to the spike. (c) Small actmty increase noted on chart 23 mms after ramp. Large increase after 75 mm ended test. (d) See Figure 3.4 3. A4-61

                                  /M8O0s,>
                             ^m oU n$7u 8 U l

6 2

                                                /
     )Nr)s                                      2 -

OO P I T I R l S AAT )N ZZO DDTI I l RR AZ l 0 2 A Al DDD N NR AAA T TD O S S. N l S h h A D 0 0T O 3 0 0S3 R h E (

       - ~

( (6

                     ,                                           l C

N E 8 R T E E 2 2 F GRR l E R 77 7897 e

  - 9 9 9                                                                        m P    1   1 1                         g                                         i RAE$

S T n O l g i o t

                        ,           g                                            a i

z 5 dr l O 1 d a g g n

                                                                            )

t a V S g l k

                                                                            /

d g f t o W c e ( M l l l P E U N - R U A B e l c n e u q e l S p m l 0 & 1

4. -

4 3 e A l r A u g i F A I l l

   -           -   -   -        -      -      -     - - -  -           _5 6       4       2      0      8 6 4 2            g 4   2          0   8                          ,

1 2 2 2 1 1 1 etsd e$Ol5;e1X Og om> 2 $ &W1ar N D D E N L U O IA _ S F 9 S S E D D C O O N R R E R E DD DD g F E E E E E DD DD R N NN M 0'dO OO E O R NN 4B BBNd r F OO OO S NN NN , 5 E 1 V mp m R m um U 0 u 01 uS C 1 S OO GE O

• o  %

0 s e c n e 1

                                              %u_                               )

i r e p

                                             %                                  U    x

_ g E

                                            %                                   k   l a

o _ / d t o

                                          %                                     W O             '             _

0 1 M ( P U T

                                                                                    )

N d R - R d e O W U n

                                        %B            -                         B    o b
                                                      -                              n 3         %                                             o g                           -

N ( r i e r r S a D U B O D r R N e C C p ( A p p

            >                       %             %                                 o 1

C o s

                           @        0 3             0 5

O 5 4 O O 3 e r _ u g i F

      -        -         -   -      - ~         -           -  -  -  -  -     0 6   4        2            8      O           2            io 8  6  4  2  0 2   2       2          m  1      '           1 3h        ' 3$gs
                                         $go"

NEDO-24259-A (from GEAP-25163-2) All of the reference rods, except the very low exposure rod. SRP 3/7, failed following the step ramp (Sequence B) f rom 8 to 16 kWlf f Q12 to 52.5 kW/m). All of the barrier rods plus a rod, SRP 3/29, containing f uel with a high O/U ratio survived this test.The results are presented in Figure 3.44. Although the burnup disparity between References and Barriers detracts from the impact of this result, the hundred percent success rate on the latter is significant. The literature representation of pcwer rearlor fuel performance

• is included to em-phasize this conclusion. The reference rod results in this range suggest that the B Sequence ramp is at least as severe as A Sequence ramps. Sequence B ramps to progressively lower terminal powers are needed to define the threshold f ailure pcwer in this type of test.

All : the bonded Cu barrier rods (i.e., barrier diffusion bonded to cladding during f abrication) f ailed with little Imr ovement over references. Clearly the Cu-Zr intermetallic layer degrades the performance Cu-barrier fuel ar must be avoided. Preliminary evaluation of the data suggests that the thickness of the intermetallic layer is more important than that of the residual copper layer in det4rmining performance. Note in Tables 3.4 2 and 3.4-3 that the test matrix included low burnup rods containing electroless copper (SRP-3/40,-3/41,3/42), copper on-oxide (SRP 2/32) and sponge zirconium (SRP-2/34). These newer barrier designs all performed successfully. 3.4 1.2.4 Conclusions Reducing the pre-ramp standardization time from 300 hours to six hours did not significantly ef fect ramp test performance. Although Cu barrier fuel (nonbonded) out-performs Nference fuel, it is not immune to failure at high burnups. All barrier fuel subjected to a single large power step ramp test at low to medium exposures survived. The development of a Cu-Zr intermetallic layer between barrier and cladding clearly degrades the perform-ance of Cu barrier fuel. 3.4.1.3 Nondestructive Post Irradiation Examination The non-destructive post irradiation examination (PIE) of the twelve rods ramp tested 8 8 at Studskvik in 1978 has been completed at the GE Vallecitos Nuclear Center. The visual examination and neutron radiography were performed at Studsvik shortly after testing, and the results were reported previously8. The additional characterization steps included profilometry and pulsed eddy current (PEC) traces. A summary of these results is given in Table 3.4-4. The PIE results have confirmed the ramp test results with respect to the condition of the rods (i.e., sound versus failed). Post irradiation characterization results summaries for three rods are shown in a convenient pictorial for-mat in Figures 3.4 7,3.4-8 and 3.4-9. The rods, SRP 2/1, SRP-3/35 and SRP-2/14, are a sound Cu barrier rod, a sound Zr liner rod and a failed reference rod respectively. The main points to note are the high permanent clad-ding strains suf fered by the sound barrier rods compared to the almost zero failure strain in the reference, and the PEC signals from the inner surfaces of the two sound rods. The high cladding strains in SRP-2/1 and SRP-3/35 testify to the severity of the test, particularly to the effect of the power increment above 14 kWlft (46 kW/m), the maximum peak power of the f ailed Reference (SRP 2/14). It is also noteworthy (Table 3.4-5) that the Zr-liner cladding strains in this test series were much higher than in similar, but lower burnup, rods ramp tested earlier 8 in the General Electric Test Reactor (GETR). Possible causes of this difference are being evaluated. The remarkable plastic strains in the sound barrier rods, compared with those in the f ailed reference rods, are shown in Figure 3.4-10. The strain values shown here and in Tables 3.4 5 and 3.4-6 do not include the strain due to ridging. A4-64

l N3GO-27ZE6-V

                                      )32om 93Vd-2519C-2(

8 e - o mOC m

         @e

z o Z

   >CM m                                                                        -

boFE1 S

   @ o >i2m' oom mmag e

2288,, zz m - AA ;E *

   ;;E AA5E                                                                      -

eOO I ~ e 3

                                                  -;;l fI   ~

Io i a s= am I I uc O e l & ot 1 o t l' - ze 8 i s a I z e U/O HGIH > [ l E $ ne m I h D $ uc O dmEW - 2 rz O rz O N w 9

h. 8 uc c o C r2 o _

uc ,rz 3N' 'd uC ,rZ o I _ , uC ,rZ feR O - l g  ; l l l [ I I I I I I i o g g y e 8 m a a u 5 = * * "

                           )tf/Wk( REWOP KAEP MUMIX AM Vt-95

Table 3.4-4 1978 RAMP TESTS - NONDESTRUCTIVE PIE RESULTS

SUMMARY

Ave. Max. No. of PEC Fuel Rod Burnup Max. Peak Rod Cladding No. of Cladding Through Wall identification Design Feature (MWdikg U) Power (kW/m) Condition Strain %ial Ridges indications SRP-2/10 Reference 16.5 39.2 Failed None None 2-4*> SRP 2/11 Reference 15.4 46.2 Failed None None 1-2*' SRP-2/13 Reference 15.4 51.8 Failed 0.08 None 2-4*> SRP-2/14 Reference 14.6 46.0 Falied None 1 2-5(b) SRP-2119 Reference 14.6 52.2 Failed 0.08 2 1 SRP-2/20 Reference 13.8 52.0 Failed 0.08 3 1 g 10 pm Cu-Barrier 58.2 Sound 0.4 19 None SRP-211 12.4 h & (non-bonded) 7g 20 U$ SRP-2/4 10 p.n Cu-Barrier 14.4 58.5 Failed 0.3 1 g4 w (bonded) w SRP-3/33 5 pm Cu-c :er 16.7 52.1 Failed 0.16 8 1 -3*) (non-bonded) SRP-3/34 5 pm Cu. Barrier 16.1 59.0 Failed 0.2 7 3-5*> (non-bonded) SRP-3/35 Zr-Liner 16.6 58.6 Sound 0.5 24 None (crystal bar) SRP-3/36 Zr Liner 15.3 58.6 Sound 0.5 20 None (crystal bar) (a)Does not include ridging strain. (b)tncludes possible through-wall sign 61s.

7 h00R ORIGWR 1 i r y -; - 3 - . - - 3. - t .

         .,              -1...      >

i  ; 3

                                                                                                                                                               '                1            -

i .

            .                    .                    .             Jj - P.E.C. T ESTI NG                                                                                                                        3 i

i. ~ I.D. SIG N ALS . 2: iO S. 20 MV/DIV k%i ,'

                                , ,                    +

l . C1n SIGNALS

                                                                     ..r-                              ;

2: 30 , g- t . l

                                                                                   *                   -                                                                        .                                                      !                                                                                 ,      \

i

            ,                 s.

• t i

            ; . l.

! . \ 1 e . w +- l 1 \

             ;                      L                                                                                                                                                         '

6 i 4 1Z40"

                                                                                                                                                                                                                                                                                                             - 20 P.E 4 l             '                                                                                                            i c ,j -                   [             -)~                                                                                                                       ',

_pggg poweg 7

         -i-                                            !               I           .

7 L28;

                                                                  . .' . .                              : tr                                                                                   >                   !                                                      18.0 kWF T
         -;   '               ' $' - M ONTICELLO - SPACE R Z r

t u g, *-. ' 1 0 A 0-68

                                                         '.(

1r V O*-360* 41_ C J -

                                              ' VISUAL EYAMINO DEFECTS OR ANOMALIES.                                                                                                                                             ,2p#hos'eSi+ec                                        a re gi' i

_i- t 1 ibt40eufgn{ -n;E a E EM;h htr P jT - 'O

          ; 7. + -
                                          !T                L_,~T-~i .[                                                      '                                   ;             .,            .l.                 .i                                                                                               -
                                          ;_ m y ..-,_.__,: _

y y ,_ p. r, p p-  ; .- ;, ,. 3 q 4, 3

7. { .-

                                                                                                                                           ,                      .                                .                  4                   ,
;                                4 j
                                                                                                                            ,I             j                                         1             1 -                                     '

4 1 6 5 ' t i . 7j '.  ! s

                                                                                                                    .y g                 -i _ - "                              .}_        . i .                                                                                        ,
          - _             $ g..
                                     -t
                                                   ., ' . .. i . i :. ... }, .                , . - . . .        ,

3  ; -. ,p _4 l t

                 !                        .t .          ..
                                                                           !-         ,                                      1
                                                                                                                                       .T.                                                     . ;,                                       . _ . t. ; ..                        .                                           ,
                          ..J .                                            3
                                                                                                                                                                                                   . . ,                            ..                                                4                                .

u.. _ e. . . .

                                                                                                                                                                      .-             4.            .
                                                                                                                          ..               1,                                   1,                 .                   ,                                      4                                                   ,
                                                             ,                                                                                                   i.                                ;               o

i. - .

                                                                                                                                    .~
                          - .. I i .             .                1-                                                   4              .I          -~4.__.

44

                                                                                                                         ;;['                                                                                                                                     e v. ,                               ,
                                    ,ye -w s

t- -,, , ,~y %- . .

                                                                                                                                                                                                                                                                                    ~.n.                  ... s. .    ,g
                                                                                                                                                                                                                                                                                                         .. p

(- g t

                                                                                                                    ,;               _p                     -                v                          <                              3,                            . yv d,..._' . u.
                                                                  & Y m-
                                                                    . . -                .                         s s
                                                                                                                                     .-                               -               , ~

g

                                                                                                                                                                                                                                              ..-v.
                                                                                                                                                                                                                                                                ;                    3            %                           %

a 1 a a _-

                                                                      . ...i .          <

_ _i

                                                                                                                                                                                 .i il l . ,
                                                                         ~
                                                                                                       'I                                                         3 D                            !                                                         !

i .  ; , t- .{-

                                                                                         .i -..-     -}                                                                               !              ,                       -                                  6 1,                                                               {                     i
                                                                                                                                                                                              .. ;' .                                                           J
                                                             . _ . . - .                                . . -       m          ;             . _.                                     4 t

t - , . ,. p (

                                                                                               .                               .                                   .                  t-l..                 l.                             .                      ;.
                                                                                                                                                                                                                                                                                                       +

i se t: > r i , l 2 f f

       }
       \

' A i

r 1 i NEDO-24259-A (from CEAP-25163-2) l 1 i P00R OR GINAL 4

• v 3

{ l PO ST- R A M P P-2/I

                                                                                 = C L A ODIN G Z R-2, a 9 '13* 0 a y o o 3't"W AL L l

l

• REMEDY : Q't MIL ON I.Q (UABCP4DED/5HOTPEENED) n J
• LOW ER NiDDLE SEGMENT I

                                  ,                                              = S ERi AL NUMBER 3 DT B-Ol3't

• RAMP TE ST AL; + 0. 0 20"

. 31,%"

  ,a GMA L5 lt ID/ I O-115 /8-36 FICAL                                    +-

lSEGMUTT SOUND ] 2 O.83* g (MONTICELLO SPACER 3 p ,

                                         ,-PR E-R A M P (ACTATI N G) PRO FI LE ENV E.LC F E v                            i . o*->    aoot <-     ,
                                                                                                                                                     '*L
                                       /                                                                                           C+ 9 4 0"

Md W hT])1 cmwe, - - ww --- -n ~nn +~ =-=w :.A

    ,p s.

9" M

                                                                                                                        , v.
                                                                                                                      ...-.,i,....-m.m.....-.
                                                                                                                             .u..    ... m m.......      .
                                                                                                              . . . . .                    .. .-                  . ~.

g 4 _ t i

                                                   ,            n   +

t , . l

        ;_           y
                                                                '                                                                                               i I        I                      t 1                                            -,                   t
        .            ,i                       i.

i Q,- +. _J\._.. 4 v gm-vs s...- % ~ ,_ A s -s - .-A -- J Tbh--_^- _ _M w I 360* klDGES ' 1%5" 1 e i Figure 3.4 7. Nondestructive Test Results - Cu-barrier Rod SRP-2/1 T t r!.-67/A4-68 {

B i P00R ORIGINAL

                                                                                                                         -                                                                                    i              a                                                                ,
          'T                          T l

t

                                                                                                                                         'i             

l

                                                                                                                                                                                                                                                             ^

] l

           .y                          ('                            ;j               ,

j P.E.C.TEGTI NCr : } y 1 .A.D. SI G N A L S itiO e 20 MV/DIV

                 .I
                                                                       ;                !                                   i O.D.' bl GN ALS 2 30                                                                                                      10/47-08
                                                                                                           '              =                                  i                                  -

2+-3 ,' ', ' ErAM PCMER- 7 2 *- 9 C *

            - :                 _ ;                                                                                          <                               l
                                                                                                                                                             ,                              IS O N/FT                                                    14 85"             >
                    !               a b,g,qg                      t S.MILLSTON i

E NACER 2- j 4 { 4 [' l!

                                                                                                                                                                                                    +

adrucams" !Ifr~ fIIbet sua' r d a. *

         .             i        VISUAL -EX                           AMS NO        y_

DEFEC.T5'GR ANOMALIE55 i

                                                                                                                                                                                                                                                                         --) {            '.- E ET BU BU
                                               ~
                                                                       ~i                        '.                                                                                                                                 . -- ' {ET an- , .
                                               , , m. . a
                                                           .o          a                   .

i

                                                                                                                .            a.
                                                                                                                                              ,                    i, --                                                         -
                                                                                                                                                                                                                                                                      .       .' .- - 3 .1 sy g;;

f } k .. ~.' q -p i :p p r p 1 1.

          .,f-m                                              :q-.                         j-             ,          .t                  y

o. g_ y 3- ,

a

                  .i r- :
                                . j .

4

                                                                             .. .- ,9 .,-q;.
                                                                                                       .}..-.r,.--         ..!
                                                                                                                                            >'                 i 1                4
                                                                                                                                                                                   +
                                                                                                                                                                                             . . }'-          d' t                +
                                                                                                                                                                                                                               .}-

4 .- a 1 .~.

                    .!.        . - , .                                                                                                                                                            1                               i i
           .L.+                 I - $

g

                                                                                                                                                                                                . .j -        -y        ,

9., .. f = .{- mj- g f. . ,.

                                           +
                                                                                                              ,.                                                                    6              I       .
                                                                                                                                                                                                                !-       ,,                 e           g      .
                                                                          ,y.                                                                                                                                                                                                      j            3

_- {p- =. 7 . \

           .m,t .                                                                                                                                                                                         f) p
                                    .. { e ; .. 3;_...,,.... --.-q.-...-.._                                                                         ,                                        A                            f.

_v,, p p,. \ f._. _, ,  ; .. t.

                                                                                                                                                                                                    !',                                                    sy                                       g irv                            Ao*/ps - .Q: 1-~                                              '.       {

t + 1 Q y1

                                                                                                                                                                                                                        -               \     j

Ag) ' . '

            <: _; . 1r                                           .X             rp. . ,                   -

t- , cy.

                                                                                                                                                                                                                                                                                            .       q
            .. . .       ,.   ;             i               3 uw t . ,.

f. kj s.- .s j ri

                                                                                                                                                              -t f
                                                                                                                        'M                                   - l'                     ;                         d M(_

y q.y .., r

                                                                       &% .(,.

7..

                                                                       -,                  r. .
                                                                                                      - a
                                                                                                           . rk
                                                                                                                                           -Ipfww-m.A
                                                                                                                                          . .i : . .

g i

                                                                                                                                                                                                      }
                                                                                                                                                                                                        , _, y pajg_44 q
                                                                                                                                                                                                                                           .n m i     at4 i            9, i  _At _t.-
             . .- -yp- . l _[- u . .f. 7 7 .}                                    m                      .- 3 .                   .
                                  +

r  ; l,  ; t '

                                                                                                           'I                           j 7 65 i,                                I}                               k'
             .           l1 * ^ } ' "                         t      ! I                  .t                                  .[.-                                                 a.

1  : > . ,

                                                              ; ... _ . 7; . q_

a

                      .; .                               -6                                                                                                                                                     g

___.q  ; _ m,

                                                                            }-                                g_                  :. .         g . ._ g._q '. y                                                                               
                                                                                          . , " _ { . _ i 'I ;.; : } t ' . ~ ',. . _ . _ '.q.
                     'f-          ' .: {'                    ~!J~!lq                         ,                    ,
                                                                                                                                                                                 .            ,. t .

g ,

                            ~

s .:4 d,: .._.ihl.--.m.}i ] , 4

                                                                                                         .exf . -.aj..              .: [ -.i[-c- - -1 ^.                         -][w.' ;.. L', .. :.                     .. ._. ! .
                                                                          .t - -                                  t-                                                           ~ T;                                 {
              ~ 4: j j e u m_i.>'.1                                           : ::f
                                                                                     .c;p    t-                                                                                    -!-              .t -              ,               t                                          ,

i

     }

I f l 1

NEDO-24259-A j  ; { l 2

c. t u

s n i e y .

! m s* = 'S R P-3 35 T # #

i e CLADDING: ZR-2 30.+'13'C. O. x 0.0 24 v!A tt i C D/i 7- + 6 - =

                                                                                                              , REM EDY : 3 MILL (CRV5T/ t. B AR')IRCOlnCM' ;                                              '
                                    ,M                                                                                                CC-E ATRUDED CN CLADDING I.D.                                                    l y

_ tt_ - i. *LOWUR MIDDLE LE6 MENT i 1 w MtLL5 TONE SPAC.! R 3:(20.93 ) - - - 4 . i

• SERI AL NU M BERt STk-04? i

                                                                                                               = R AM P TELT alt '+ 0.O'+5 "                                                               ;

i - - _._.___L____.._ - , - 0 +M",  ! 1 -

                                 ,bFRE-R AM F> (ROTATING) PROFILE ENV ELOPE (SEGM E NT.GOU N--D f -                                                                               i                        !

i . o'L->o cci- (-  ;

                                    ,                                                                                                                 1
                                +m~                                                       ~/                 '
                                                                                                                                                                              -}-.                                     l A                    G                   ; @ -:

• 32.+c .

                                                                                                                                                                                .o        "

l i 4.W nw e 2c.# n n 24 W , s.,o' nse Aw l l_< j -

                                                                                                                                      ,     !                                                        n
       ]

P T{1gT' --> g {My-E APAhDLNG MANDRIL k ,

                                                                                                                                      .                  Oa                                           n N SEY$                                     YIYYY5l.5 C:~~.l ::.sT"'

2........

                                                                                                                                                                     'm===                   -               " * ~

i.  !' i

                                                                                                                                                                                                         ~

i  ! 9 .. M

• 4  !

         .

• t i

                                                                                           '          i        I s              ,

l '#  ; ,

,        !            .;                   .}          .y_                                            ,

e -j , 1  !

                        !                                  !                  ,                       >-                            !                      +

i

                   . :            .          t                                ,

s

                                                                                                                                                                            +
                                                                      .\                        "p \

f, [ i4.A; n *

                                         ~           . :4
                                                        ^
                                                                      .~

V .%i

                                                                                      ,'.          ., i
                                                                                                    '+
                                                                                                                .,J-
   ,                                                        ,                                                   '?

1

I ! d ,f 36d' RIDGG~S. k } j , ._' -~~#

i ,  ; > i ' 2 L + $' 4 .

                                                                                                        !                                       i n                                    .
                                                                                                     .}                   :-                                                               '

i'

                                                            ,                                                          .p                                    4
                                                              ,                 i j                                i
                                                             $                                s          i Figure 3.4-8            Nondestructive Test Results -

Zr-liner Rod SRP-3/35 i A4-69/A4-70 [

A 1

    \

P00R ORIGINAL { l 1 i 4

                                                                                                      =:                                             ;                            ,            u;                                                                               l i . .                                                                        ;            .t                  e.             i u

g

                            ;                                                 A E.C. TE STINO :                                                                                                                                                                  '
                                                                                                                                                    ^                                          '
                     ^[

I.[1 SidNALS 'ee 30- t 20 MV/DIV O.Q SIGNALS 2:: 30 -TMR U ?/310

                       ' 'l  :                                                                                                                                                      .               .

iq 2*- z sz'

                                                      *                                           ~8'                                                                                                                                  IM 0"
                     ~~ t                                                                                                                                                                                 500 -

j' ' l THkU[52B' 16 0 '-

                                                                                                                                                                                                                                          -T H R U ? /'t 2O
                                                                                                      .                                                             .                    . i2.90 r-                                             i s* - 6+ * -      -
                 "          -l i

l't. 3 0" 4' TH pq R.U .46 /500 8

                                                                                                                                                                                                                                          - TH R u ?s/+ 10 _*

3 12'12 n 26t*-311* V y! 2.76 a 19 .3 0 " - 10/16 0

         *                    '                                                                                                                                                                                 b          Y                                          1     ,2 q" MONTIC ELLO                               SPACER                 't                                                            _                                                    o/3g o
                                                                                                   ~*                                                                                          -PE AR POWE,.E

_I.304*-351' l't.O KW/ F T l9,7O" 11.8 9 y "V NV 1ibY W'"

• f 12 ** a w" 12.H "/186*t 254 12.12"/i5':CXf DE $ PALL 7

           .;                            ViSU AL EVAM:
                                                                                                      =

12.1273+*:"X-M A RX" J JG L_ L "y-MARK" W ; 4 '.,. A . _ W _ \ N- . L 1

                                                                                         \.       ..-

f. I I. ~i.. .. .<  ! .. 4 )

p-- . .

                                ).w  _f

_ - L . .. >

                                                                             ~ q .., j ;_ ; c . H,._ a g ;
                                                                                                                                                         -         -p          _ ; . . . .                             ..

p ig.. 7

                                                                                         >           - , .                                                                            3
                                    1                                 4                               - . . - . , -                                                                 A I
                                                  "                                 ~
          .5%                        .l                      ~.                                                                     g
         . g), , ,                                                     .g.                                 -l..                                                                                                               g
                                $. 4 7                . g.
                                                                      .4,                                                       : a-  ,
                                                                                                                                                                              --                                              p 3                            ,                               .t

! 97 * ., e  ; l g +~ g 4'o. - ' ' ' ~ ~ ~ ~ ~ ' ~ ~* ~' ' '

                                                                                                                                                                                                             't             i p'                                 [MO*'~    n                 '*~ -~ ~ 'i                                      .                                    .

fc, .%. A,  %

                                                                                                           -                                                                                             -                                p.-

3.: .. N }$if . , ~;,

                                                                                                                                                    -t a          v               ,p. , :.

n

                                         .. . o*-       r ,

1. _ - -3 .-p . __

         .pp. , . .~ g . ~. . 4 ..'p.L i~ ..y. .' _ _ -
                                                                                                                                 . f, i
                                                                                                                                                                                                                            .-g          - $$Q, Q g ggg
          -,                      . ,.                                                                     *

• e e 2.g .f ,_ '*., tL ..- - -+ 4 gy g

                                                                                   ~f -g _.' ,
                                             .s                       ;),                                                               \

y2- - - - - n  : ,f.- $- 4 .,,4m. , ..my g 4 ,.p ~~.-.p14 7p.-p a y ~..,+1 . M g h.,l. -% 7

                                                                                                                                .4-    . =. ]7 .~      r ; . - j .

7 r _ m ,4- - - , e4 4 g, _ - r..

                                  ..M,A....
                                                ~>__...._.-,.. 4 _  '
                                                             . ..., m4. , .J ff .           .7..        .4
                                                                                                                       -,j....f...'o                .~.L I~
                                                                                                                                                             .    ~1.,

J J - , .

                                                                                                                                                                                                   -{.

4 5 4

                                                                                                                                                                                                                                          .j,,
                                                                                                                                                                                                                                .ey - .-i,J - - M- .{..

G. i6.4ns4{.ab % ;-w., Z ' ~,. aw-4, i . . b ' i' 7.c.n'.- .k. ,

                                                                                                . p Ld'O A 4A44,,- h 4~i~dm 6 . .. ! # L. _ ;

v., L , , i . .- M

                                                                                                                                                                                                                                                       +..  .i 3      ,

i .. I m N, I I

NEDO-24259-A (from GEAP-25163-2) , PADR ORIGINA0 1 s PO ST- R AM P. -- -

• CL A D DI NG : ZR-2,0.4 9 3"O C X QO3i WALL

                                    "~

• AEMEDY NONE (REFE RENCE)' '

                                                                         '

• UPPER MIDDLE SEGNENT
• SERIALNUMBER 6 8D07-3 y
• RAMP TEST AL + 0.013' s - n, 50 MENT FAILED l 9 2 2.31' g 1.Cf-) 0.002*i-  ;

5,

                             $, MONTICELLO SPACER S                                                                                                                                   u                &

t O.4960

                                                   -PRE-RAMP (ROTATING) PROFILE ENVELOPE 5
                                               /                                                            5
                                                                                                                                                                                                                 /

A 9' q . - %':' .. Nd' - hj! g 29B"/ 75* WAT F ,. 07.7.1 NGb s n

                                                                                                                                               ,3. g ,, m m ,. ,
                                                                                                                                                                                                                             ~
                                                                                                                                                                                                                       ~'

a e a e t I s- e f e i , 7

• a

                                                                                                                                                                                                                - sl a

J l l 9' -

                                                          %                                                                          5                                                         - -
                                                                                                                                                                                                                 -4 m                         ~~                      ~             .c          ,              n         s .
                                                                                                                         /~                  ' ~

s W s -+ - y.. ~ 3p m

                 .                                                                                                                   ,               4      .            _            -

y

                                                                                                                                                                                    . .. t
                                                   .                         1                      .
                                                                                                  ~'                                                                                               '

a - -. . r s' ^ . y1

                                                                                                                 -                - r, -
                                                                                                                                                                                                .j~

s'

                                                                                                                          .-g
                                                             -L 4
                                                                         'i

_.i.

s .- r - - _ . . .- e .

                                                                                ~4            54      .. .,                   ---. e }                                   ---[---                      --.,-     - y .

Jf TI , 2 .I[i r7 '.. ;t;-

                                                                                                                                       - p;g
                              ! " .; ' i                          '
                                                            . ' '.:. ~p .

4 -t- .- '. [1, , . ) j , ,

    . .. J -           ..c.~._[        _ I l ili_.;                 N OMId b O Y '~                                                      d        Na. . L '                 2' f          Ida- L.a                  .     --

Figure 3.4-9. Nondestructive Test De ta - Reference Rod SRP-2/14

                                                                                                                                                                                                                                  /

r A4-71/A4-72 /

                                                                                                      ~

NEDD-24259-A (from GEAP-25163-2) Table 3.4 5 CLADDING STRAINS - Zr. LINER RODS Average Maximum Peak Peak

    - Test                                    Burnup                       Power                      Circumferential Reactor              Rod I.D.           (mwd /kg U)           (kW/ft)         (kW/m)            Plastic Strain (%)

GETR SRP-3/17 7.9 18.0 59.0 0.1 GETR SRP-3/18 10.1 18.0 59.0 0.2 GETR SRP-3/19 8.8 18.1 59.4 0.2 R2 SRP-3/35 16.6 17.9 58.6 0.5 R2 SRP-3/36 15.3 17.9 58.6 0.5 The PEC signals in SRP 2/1 and SRP-3/35 were a consequence of ramp testing. I.e., the signals were no recorded during pre-ramp characterization tests. As shown in Figures 3.4-7 and 3.4-8 respectively, metallography samples were selected at PEC signal locations to try and determine the cause of the signals. The SRP-2/1 samples have not yet been examined. The metallographic examination of the SRP-3/35 sample has been in-itiated, and preliminary results are described below; but no obvious cladding feature on the inner surface was located to account for the PEC signal in this rod. 3.4.1.4 Destructive Examination - Metallography Five of the 12 rods ramp tested in R2 in 1978 were selected for destructive examination. Among the objec-tives were:

          *     . Investigate the cause of the PEC signals in the sound rods, SRP-2/1 (Cu-barrier) and SRP-3/35 (Zr-liner)

• Determine the thickness of any Zr-Cu intermetallic layer in SRP-2/1 and generally characterize the Cu barrier
• Characterize the state of the Cu barrier and the Cu-Zr interface in the failed barrier rod SRP-3/33 Work was initiated on the sound Zr. liner rod, SRP-3/35, during this period and preliminary results are reported below.

A transverse section was taken in the vicinity of the PEC signal (Figure 3.4-8) and ground ihrough several planes bracketing the signal location. The sample was polished and examined at each plane, and a small f abrication flaw (Figure 3.4-11) was noted. More important features were the many micro-cracks around the clad-ding inner surface. Examples are shown in Figure 3.412, and the distribution of the cracks around the liner inner circumference is represented in Figure 3.4-13. The depth of the microcracks was about 10 to 12 pm, and there were more than 200 in some planes, apparently depending on the local cladding circumferential strain. Addi-tional metallographic sections were selected from SRP-3/35 (see Figure 3.4-8) and the number of microcracks were related to local cladding strain and maximum nodal power. These data are tabulated in Table 3.4-6. Further evaluation to determine the nature of the microcracks is in progress. From the depth of these cracks and from their uniform depth of penetration,it appears that the zirconium next to the fuel (within 12 pm of the inner surface) has changed its properties to allow nucleation of micro-cracks. However, beyond that depth the properties of the zirconium remain such that PCI cracks cannot propagate, even when the strain is high. The observed crack depth corresponds approximately to both the range of fission fragments and, based on Kleykamp's work," to the expected diffusion depth for a significant concen-tration of oxygen from the fuel. t. A4-73

NED0-24259-A (from CEAP-25163-2) 08 9 REF -- FAILED (6) E Cu - FAILED (3) O Cu -SOUND (1) 3/36 (b) A A Zr -SOUND (2) 0.5 - a - 0.864 mm WALL THICKNESS 3/35 (b)A b - 0.711 mm WALL THICKNESS 2/1 (a) 0 0.4 - 9 E e t; 9 e y 0.3 - t 4 5 2/4 (a) E 5 l 0.2 - 3/34 (b) E E 3/33 (b) 0.1 -

                                                   @ 2/20 (b)    $

2/13 (a)

     ,                  I    2/10 .(a) I 2/11
                                         -    (a) 1.2/14 (a)   I          l 30             35             40         45            50         SS             60 PEAK RAMP POWER (kW/m)

Figure 3.4-10, SRP Segment Cladding Strain Due to Power Ramp Testing A4-74

W NED0-24259-A (from GEAP-25163-2) Table 3.4 6 CORRELATION BETWEEN MICROCRACKS AND CLADDING DUTY IN SRP-3/35 Axial Local Cladding Local Number of Location

• Plastic Strain Peak Power Microcracks in (cm) (in.) (%) (kW/m) (kWitt) Cross Section 35.18 13.85 0.5 58.4 17.8 110-1486 37.72 14.85 0.5 57.4 17.5 115-2930 41.20 16.22 0.5 55.4 16.9 110 44.5 17.5 0.4 51.5 15.7 170 46.2 18.2 0.3 40.5 15.1 83 49.5 19.5 0.2 45.3 13.8 41 51.3 20.2 0.1 42.7 13.0 9 60.5 23.8 0 29 9 9.1 0 82.0 32.3 (plenum) 0 0 0 0 eDistance from tip of bottom end plu0 b Several planes examined The thickr ess of oxide patches on the liner inner surface were about 2.5 pm. The oxide thickness on the outer surface was in the range 11-17 pm with some circumferential variation. This may be compared with the mean oxide thickness of 9.4 pm reported 8 for SRP-3/17, -3/18 and 3/19 with one less cycle of exposure. A substantial fraction of the corrosion hydrogen has been picked up by the cladding; in the plenum section, but not in fueled sections, this hydrogen is concentrated in the Zr-liner.

3.4.2 Fuel with Cladding Perforation (J. H. Davles) 3.4.2.1 Introduction There is a need to evaluate the post-defect performance of barrier fuel relative to that of conventional fuel. An experiment has been designed to compare the irradiation performance of Zr-liner fuel rods, each having a hole drilled to perforate the cladding, to a similarly defected reference rod. As described previously', defected standard fuel rods can be operated successfully for long periods without severe degradation or secondary damage, provided heat fluxes do not exceed some critical value. An empirical relationship between this critical heat flux and the time to failure (severe secondary damage) has been established by Locke" and this relation-ship has been used to design the experiment. Defected BWR 8 x 8 fuel rods operating around 10 kW/ft (32.8 kW/m) should operate successfully (I.e., no major secondary damage) for up to a year. In the current test three Zr-liner rods and one reference, all artificially defected, have been required to operate for 1900 hours at a steady state power of 35 2 5 kW/m (10.7 kWlft).The relative performance of the Zr liner and reference fuel rods is to be determined by post-irradiation examination. 3.4.2.2 Test Rod Design The design of the test fuel rods is depicted in Figure 3.414 and additional design details are provided in Table 3.4 7. The length of the enriched fuel column is about 42 cm. The artificial defects are single sma!i drilled holes at the location shown in Figure 3.414, which were mechanically $ rilled through the cladding prior to fuel loading. Hole diameters are given in Table 3.4-7. The defected rods were filled and welded in dry helium, but no precautions were taken to preserve the helium atmosphere during handling and shipping. A4-75

I NEDO-24259-A (from GEAP-25163-2) MAG 250 X Figure 3.4-11. Fabrication Flow in the High Power Region of Zr-liner Fuel Rod SRP-3/35 A4-76

NEDO-24259-A (f rom GEAP-25163-2)

                                                                                                                                                                                                                                                    . ZlRCALOY i

l l ZlRCONIUM I f 1 C578-20 (a) MAG 500X i ZlRCALOY (

                                                                                                                                                                                                                                ,                         ZlRCONIUM w'

C578-21 MAG MX (b) Figure 3.4-12. Microcracks in the High Power and High Strain Region of Zr liner Fuel Rod SRP-3/35 A4-77 , l l

NEDO-24259-A (from GEAP-25163-2) o* l l ii er #

                                                                                            /

i m 3 90* 270* , g,3 (b) 6 180*

 ~ 148 MICROCR ACKS Figure 3.413. Locations of Microcracks on Inner Surface of Zr liner Fuel Rod SRP-3/35. Crack Locations are Marked, but Are Not Drawn to Scale. Locations Marked (a)and(b)are the Areas Which Appeared in Figure 3.4-12(a) and (b) Respectively.

A4-78

4 NEDO-24259-A (from GEAP- ?S163-2) TOP , I I

              \        /

AL Jk E3 0 0 0 0 0 0 5

                         ,         SPRING n

i y N ATUR AL PE LLET

                       /

5 b DRILLED HOLE

               #%                  PERFORATION
               ,/%,
                  -,8 Jk                        ENRICHED FUEL
                     ,/
                ~      ~

l I '3 N ATUR AL PE LLET j

                      /

V 1 i

               /         \

U l 1 BOTTOM l_l

                   .=_
                      ~-

s_ Figure 3.4-t4. Perforated Fuel Test Rod A4-79

NED0-24259-A (from GEAP-25163-2) 3.4.2.3 Irradiation The rods are being irradiated in a test rig in Loop No. 2 of the Studsvik R2 reactor. Loop No. 2 is a pressurized light water loop used mainly for testing BWR fuel rods under operating conditions. The features of the reactor and the primary test loops have been described previously? The power levels of the fuel experimentt in R2 are controlled in three ways: compositicn of the reactor core loading, choice of reactor power level, control rod shimming. Power levels in the loop experiments are monitored calorimetricclly using thermocouple and flow rate measurements. A special startup procedure (Table 3.4-8) has been established for the perforated fuel rod test to ensure that there is no buildup of destructive steam pressures inside the rods during startup. This pro-cedure, which has bcen demonstrated to be effective, applies to all startups during the course of the experi-ment. The test is scheduled to run for six reactor cycles. Table 3.4 7 PERFORATED ROD DESIGN DETAILS Hole Size Cladding Diametral Fuel Pellet Fuel Design Feature (mm) Wall (mm) Gap (mm) Diam (mm) Enrich. (wlo) Reference 0.15 0.86 0.23 10.57 2.85 Crystal Bar Zr Liner 0.15 0.86 0.23 10.57 2.85 Crystal Bar Zr Liner 0.25 0.86 0.23 10.57 2.85 Sponge Zr. Liner 0.15 0.86 0.23 10.57 2.85 Table 3.4 8 SPECIAL REACTOR STARTUP PROCEDURE Minimum Time to Complete R2 Power Range (MW) Power increase (minutes) 0.11.0 10 1.0- 5.0 30 5.0-10.0 10 10.0-20.0 5 20.0-50.0 No restriction Although all four fuel rods are operating within the specified peak power range of 35 5 kW/m, there is a . flux gradient across the test rig, and two rods are always at slightly higher powers than the other two. The reference and the crystal bar Zr liner rod with the smaller hole were selected for the higher power locations. Typically, the other rods run at ~13% lower power. The peak to-average power ratio along the fuel rods is ~1.16 and the power level at the axial location of the drilled holes is ~90 percent of peak.The test rig is in the B3 leg of Loop 2, where the direction of coolant flow is upwards. The coolant pressure is set at ~8.2 MPa and the calculated cladding surface temperature at the peak power location is 293 to 299'C. ) Although the relative performance of the Zr-liner and reference rods is to be determined by post. Irradiation examination, a measure of the state of the fuelis provided by the level of fission product activity in the loop coolant. However, it has not been possible to use the normal loop activity monitoring system, because the activity level is too high and the Cereakov detector becomes saturated. Therefore, test progress is being monitored by the radiation levels registered on area gamma monitors (plastic scintillation detectors) located in the loop machinery room, and by occasional removal and analysis of loop coolant aliquot samples. A4-80 i l

NED0-24259-A (from GEAP-25163-2) 4 During normal operations, when there are no fission products m tne loop coolant, one gamma monitor or-dinarily records radiation levels of 2 to 3 mR/ hour. For radiological safety considerations, an arbitrary limit of 30 mR/ hour has been set for the current experiment. If the time averaged reading over several days exceeds this limit, the test may be interrupted or prematurely terminated. Output f rom the area gamma monitors and from the appropriately decalibrated Cerenkov detector (raised discriminator setting) are continuously recorded on chart paper during the course of the test, as well as in the reactor process computer. Reactor power and coolant pressure levels are also recorded. Snapshots from the chart recording during the first cycle are shown in Figures 3.4-15 and 3.4-16. The output of the controlling radiation monitor is on a pseudo-logarithmic scale so that small dif ferences in signal height on the chart paper in Figures 3.4-15 and 3.4-16 represent substantial changes in activity level. ~ The periodicity in the activity levels evident !a Figures 3.4-15 and 3.416, and its correspondence with small periodic decreases in coolant p essure is therefore considered significant. The rapid regular decreases of the loop pressure f rom about 8.2 to 8.1 MPa correspond to those times in the duty cycle when the heater, associated I with the loop pressurizer, was switched off.This effect of pressure on loop activity has been reported previously by Forsyth et al'. It appears to be more complex than simple aspiration. but it may be a primary mechanism for release of fission products from defected fuel. Figure 3.4 "I was recorded during reactor shutdown and the relatively large pulses of activity may be associated with the phenomenon of iodine " spiking," which is well known. At least two loop coolant samples are collected and analysed for each reactor cycle. (One sample is taken during shutdown to establish background level and the second is taken at a convenient time close to the end of a reactor cycle to maximize equilibration of 5.3 day mXe.) Sample size is about 20 ml (total coolant mass is

  ~200 kg), and the samples are transferred to the Hot Cell area for analysis by gamma spectrometry using a calibrated Ge (Li) detector. The main fission product species contributing to the sample spectra are SXe, mmxe, mye, a**Kr,88Kr and e7Kr. lodine and other fission product activity levels are maintained below detection limits by continuous operation of the loop lon-exchange purification circuit during both the irradiation and shut-down periods.

3.4.2.4 Results and Discussion The test started on November 22,1979 and two irradiation Cycles were satisf actorily completed by year-end. in Figure 3.417 the output of the controlling area gamma monitor and the rod peak power (averaged for the four rods) are plotted as a function of time.While rod power remained very constant throughout this period, loop coolant activity rose steadily throughout the first cycle to twice initial levels. A step increase in activity was noted following the second cycle startup and is attributed to the well-known " spiking" phenomenon. However, the activity level appeared to decrease during the remainder of the cycle and at the end it was comparable to that at the end of the first cycle. This is confirmed by the results of the water sample analyses, which are shown in Table 3.4-9. There is little difference between the two sets of analyses taken near the end of the first and second Cycles. A4 _ . .

2mg,wOwf>

                                                                          , nog n >?N$&f m                                                                                               .
  .y                                ,'9

a. ,

                                                                             .      ._ a ,

u ],

                                                                                                                      .g j_                                _ _---57--. .-__ ._ _ _
                                                                            .                                             ^_

_ {_ _~_' . .- .

                                            ~.

_ . _ ~' _.. .. . _.

                                               ~. ._..                  . .

j ._ .~. _ _.. .. - n _{

                                                                                                                                    .g                         j,,,               o

_. 1 9_ ~ ,_ _ it

                                                                                                ~

_ a r _ _ _ .. ~-~ _ ._ - _ _ - _-,'f' _ - e p _~ , ,_ . _- O

                                     .      ~. .                                      _.               _

_ ~ ..

                                      .~
                                             ~ . .,

N3_ . t e a

                                                                                                ~
                                                            ..                                                                                                                    t

_ S y _ d a

                                                               .g

_. - D e _. ._ _ ~~ _. _ ~ . E _ t _. ~) _ E - S R P h _ O _

                                                                                                                                             -     S       /

m g n T

                             ._                                                                              T                                               c'                   i r
                        .                       _...                    __                .  .                                                     R                                u
                        .. _. _                                             _             ._                 M                                     A 2

D __ O __ 1 M H C =- er

,.                           ._      .~.                                                                     A                                                                      u oW                     _
                                 .   . E. .o ,__._
                                            ~_
                                                                        .             _. -. .        s
                                                                                                     '        M                   __                        -

_. s s dl _. . O[gA M ._ Om _ __ _ . e r

                        .                    U                 ,_.                     .

G P

              ' . _ _._S _
                                      . S E                       _._     _ . ___ _.
                                                                                                       ._. R A

E .

                                                                                                                                                     . _.            __             p o

o R -e _ _ . . L A 4

                            . ,             P P                                         _. _             .     (                               .

_. - d _ Y . _.._ - - n _ . O __ _ a O ._ T Ll

                                                                  . _                                  . I V                           ._
                                                                                                                                                                             -      y a              _.

_ I it _ T _ _

                                                                                                                                                                             -      v C                                                                    i

_ _ _ . _. A

                                                                                                                           . s.                                              _.

t c 2.. A

                                                                                                            .P

_. O _ p

                                                                                                       . O

_. _ o o J, , L. . L _ _. n . _ __. . e e

               - l4l4s 4 I .-
                                                               .4 t

e w

                                                                                                                                                 . _                               B
                                                                                 ... _      . _ . __ .                                          _. ._.                              n
                                                                                                                                                                     .              o     _

j l i _

                   .                      .                 _. 9                                               _

t a

                                                                                                                                                                     ._..          l e

r

                                                                                                                                                     . _.         . _.._            r o

j . 4

                                                                                                                                                                   ._.             C 5

_ . a _. . 4

                                                    -              .             _ ... .__      .                                                                                   4

_.. _ 3 e

,,                          .                                          .    ,,jq,g;                            _1                                       .

r _ 4_ is_ _ _. . u _

                                                                                                                                    .__~. ._               .

_. . .. g _ i _ _ .__ _ . F

,e            j.                                    9          ,,,g.               j .              ~

_ m 9 ,_ - .

w. _

2I p,,l5

zmg wygyws> i

                                                                                                                                       ,Ea                      $mg3w~&W6
                                     -                               4 ._
                                                                                                                       ~,..   ,
              ~-                     -

_. - . m _.,_

                                                                                                                       ~~_    .
                                                                                                   . _. , f{
                                           ,3                                                  .
                                                   .                                           _                        ~.
                                                                                                                       ~. ,       ,
    ~_        -
                                        -. , ,p                         ._

4. ;& 4 ._ g

                                                                                                                       ~
                                                                                                                                         ,   I           ,,..                                    i    ,!,                  ,    i            ,  ;

_. ~ _~ *. . .

                                                                                               .                       ~.%                                                                                                                                      j           n

_. - _ _ _. _ w

             ~
             ~
                                                            .           _ _.          _        . _                                                                                                                                                                          o
          -  ~

dt u h

                   -                    -                   _                                     _.                                                                                                                                                                      S r

_ ._ .. D o E t c _. E h a _ _. }_. P S

                                                                                                                                                                                              /

m c R e ____ T q, .}e~ _. . R 'j 21 r i* *.

                                                 .     ,4 i ._ .. ,.      _

i;

                                                                                                                       ~                                                        A
                                                                                                                                                                                                   ,I,            - 1,I'                                         j e

fp

                                                                                  . .                                                                                                                                                                                       t
                                                                                                                             .                                                  H -'                                                                                       f C                                                                                          A y
                          .                    -                     4g,,                                                                                                                                                  ,1i        Iji l
                                                                             .                                                                                                                                                                                              t
                                                                             .                                                                                                                                                                                               r
                                                           ->           ._ .          _       _                          )

3 o 2 h

                               ~                       .
                                                                                              .                          R         ,_
                                                                                                                                                                                                                         ,                                1j S

e g '3- l1' I i _. - _. R

                               ~                       .. _

O 3 r u T I N s s

                                                                             . l 9,.j.

O ., _ ' e C] i - r o7 M_.gR4_ gN OC 3 3 P _. _~__ .g gAM._ . p ;_ A_ . p o

   . ,E                                                                                                                                                                                                                                                                .

Rg .e M . C_ . o U S __. A .- _ _. L

  .lRl S

E _,g{ G A .

                                                                                                                                                                                                                                                             .I d

n a P

                                                           .                _    _.          . _. .                    E _.

R _ ; y P _ _. A - t i v O . ( .

                                                                                                                                     .                                      -                                                                                               i O
                                                                                                                                ,.                                                                        -- .                                                       -      t c
  . ,                                                4;.;.;4                                 . 9,4 L.. .                                                                                     .
                                                                        . .                                              T

_ . _ _. i _. A

, o V

I T C p o o

                                                       .                                                                         _                                                         -                                                _                               L

.. _ A ,

                                                           .            - .                      . _.                P                                                                                                                                                   n

_ e O_._ O . L e w _. ._ 2 t e B j'I,

                                                 . 4_4. ,p 3 .. . _

j " - n

                                                                                                                                                                                                                             ~                                         _      o
                                                                                                                             .       _         -      _.                                                                     ~
                                                                                                                                                                                                                             ~

i t a z _ _._..g 4 j ,. .

                                                                                                                                                      .                                                                      ~

l e r f.y' l, .J

                                                                                                                                                       .                                                                                                                      r
                                                                                                                                                       .                                                                                                                      o C
                                                                                                                       ~. _
         .   'l                 r, . ili                               a}             .                       ,+'                       ,                                                                             j                     ,  i1;                ;              .
                            .                                                                          .~                                                  _

_ 6

                                                       .                     .                .                   -                               .        .                                                                                                           _     1
                                                                                                                       ~ _.          .                                  .

_ 4 g,__. -

                 *.                   .s         .     ,p               ,.; .             1.     !j                   '                      ;                                      ,

li. .a ' .nr ,. 3 e r

                          -                                             _                                                    . _ _.                                                                                                                                         u g
                                                                                                                                                        ,                                                                                                                    i
                                          .g,,                                                                                                                                                                                                               .j t;

I. , F Z._. _ . . 1;

                                                                                      . t,

_ I. _ i _ __ . . o;

                                                                                                                                                           ..           . _.                                        n                                  O%

p. . _ . Q* -w.- . .g

6. . :i;.,,,, ,

          .                  .~ -                       . . ;i -_
                                                                                                                                                                                            -      . ~- _ . .
                                                                     !                             ,,1 ppIcu   o

NEDO-24259-A (from GEAP-25163-2) LL AUVONyr 010E H38W3330 NMOO10HS 373A3-dO-ON3 a cP 8 a R 00 8

                    %                      9               _ .       l g

0  ! 3 O o 8 -

                                                             ?

e 9 5 a o O e 9

                                           ^

_ e e e tx o O b o 5 y

                                                             =g   ~
     ?///l4kE*kkb!bb5W?!!/l/                                    0 5
        &                                  8               -

S 8 p e iS

                                                           - a    %

B 9 i

."_    @o                                  G              ~
                                                             '    ?
 " V /4 $ $ $ $ $ $ $ 5) Y//4                                     1 O

O O m

                                                          -  ,     a
                    %                      8                      3 2

m 2e w V A o O O E6 mg _ o A N-b 3$ KO 4 D 0 R Q 9 A

                                                    'O Ne S
 "i u                    00                   8 o

5 1 m 1 2 o h 8

• o 0 -

23 O O gj N 5 3 6 _ e a O O OO lf. l

      .     .          ii   , , , ,      ,     , i           g_f_

gg g g oommo e e n n (w/MM) g.0L x H3 mod HV3 Nil 008 NY3W (WHW) HO11NOW VWWVD V3HV A4-84

NEDO-24259-A (from GEAP-25163-2) Table 3.4 9 WATER SAMPLE ACTIVITY ANALYSIS - DATA

SUMMARY

Acilvity(*8 (Ci/ml) December 3,1979 December 5,1979*8 December 19,1979 Sample Date 07.04 10.06 07.00 Nuclide Half Life Time 1.44 x 10-d 2.25 x 10-5 1.55 x 10-4 mXe 5.29 d 2.87 x 10-e - 2.86 x 10-5 'L*Xe 2.26 d 9.09 x 10-5 - 8.42 x 10-5

'35Xe            9.2 h(c) 1.46 x 10-5                        -           1.26 x 10-5 es*Kr             4.48 h 1.11 x 10-5                        -          0.96 x 10-5 STKr              1.27 h 1.28 x 10-5                        -          1.29 x 10-5 saKr             2.80 h notes:

a) All activities corrected for decay back to sample time. b) Background sample taken during shutdown. (Note that the fission products are being sinpped from the coolant. The time constant for this process must be established before quantitative release rates can be determined.) c) Effective half-life during irradiation much shorter (N1.8 h) due to neutron capture. ACKf OWLEDGEMENTS T'ie authors of Subsection 3.4 gratefully acknowledge the help of: K. Saltvedt and his staff at the R2 Test Reactor, Energiteknik AB, Studvik, for help with both the power ramp tests and the irradiation of fuel with a cladding perforation. R. Forsyth and his staff at the Studsvik Hot Cells for their assistance with the defected fuel tests. C. M. Berry of NFSED directed the f abrication of fuel rods with cladding perforation. C. C. Guitton of NFSED assisted with design of the perforated cladding test fuel rods. R. E. Smith of the Irradiation processing Operation for hot cell metallography. G. L Holloway of NFSED for nuclear physics support. A4-85/A4-86

NECD-24259-A (from GEAP-25163-2)

4. TASK lil. DEMONSTRATION 4.1 OBJECTIVES

1. Design and manufacture of PCl-resistant fuel for demonstration of PCI resistance under steady state and under power ramp conditions.

2. Irradiate, test, and evaluate the performance of the demonstration f uel in a commercial BWR power station.

4.2 SUBTASK IH.1. DESIGN AND LICENSING OF DEMONSTRATION FUEL (J. A. Baumgartner and C. C. Guitton, NFSED) As was mentioned in Section 2 of this report, the demonstration is planned for Quad Cities Unit 2 starting in Cycle 6. This will require delivery of the 132 bund!es of barrier fuel in August of 1981. Specific design, manufacturing and licensing schedules are now being planned censistent with that delivery date. 4.3 SUBTASK lll.2 FABRICATION OF DEMONSTRATION FUEL 4.3.1 Zr liner (D. E. Allen, R. E. Donaghy, and R. J. Mack, WMD) In PHASE 1 Zircaloy-2 tubeshells coextruded with zirconium liners were obtained from Teledyne Wah Chang Albany. Liners of two purity levels were used: crystal bar zirconium (oxygen content <200 ppm) and low-oxygen sponge zirconium (oxygen (600 ppm). In this current report period four tubeshells coextruded with liners of low oxygen sponge zirconium were received f rom Ugine Aciers, and these have been evaluated. Figure 4.3-1 is a photomicrograph from one of these low oxygen sponge zirconium-lined tubeshells after an anneal at 6281 21*C for ~11/4 h. A portion of each tubeshell has been processed by GE to produce tubing, and evaluation of the tubing is now in progress. 4.3.2 Cu barrier (W. T. Grubb, CRD; R. E. Donagny, WMD, and R. J. Mack, WMD) A microstructural comparison was made between;(a) electroless copper plated onto autoclave-oxidized Zircaloy and (b) electroless copper plated onto oxygen-oxidized Zircaloy. The former was prepared at the facilities of the GE Wilmington Manufacturing Department (WMD)in Wilmington, North Carolina, and the latter at the GE Corporate Research and Development Center (CRD) in Schenectady, New York. The e.aluations were done at CRD. The salient difference between the two materials is the oxidation procedure. The material designated WMD was oxidized in steam at 400 *C at a pressure slightly over one atmosphere (~0.17 MPa) for ap-proximately 14 h, while that designated CRD was oxidized in gaseous oxygen at a pressure of 0.1 MPa (1 atm) at 400*C for 24 h. In both situations the oxidation step was done following the etch treatment in an ammonium bifluoride solution *. While the plating procedures were similar, the CRD specimen had a thicker copper plating (13 0.7 pm) than did the WMD specimen (10.610.5 pm): at CRD the plating time was extended for this specimen. Metallographic examinations were done using a tapered section to enhance the apparent thickness of the oxide and the copper plating by approximately 10 x. Results are shown in Figures 4.3-2 and 4.3-3. The structures of the copper plating were compared by scanning electron microscopy directly on their surfaces (Figure 4.3-4) and in cross-section after etching in a mixture of nitric, acetic and phosphoric acids (Figure 4.3-5). Finally, the copper was chemically removed from the tubing (using dilute aqueous nitric acid) and the underlying surfaces were compared by scanning electron microscopy as seen in Figure 4.3-6. A4-87

NED0-24259-A (from GEAP-25163-2)

                                                                                    %       ,                                                  /   N.
                                                                                                                                                      ^
                                                                                              ' ;-                                        ,_ 4lN
                                                                                                                                                 ;                  zr uner
                                                                           \                    v                         v.                     9    :
                                                                                                                                          ,h,[

g d

                                                                                                                                                    ,          'A
                                                                                                                             - ~;                  &,   '
                                                                                                                                                          ,, J' y              -

6 ss

                                                                                                                                                                 , ZlRCALOY-2 E'
                                                                             .                                    t i                            j            , , , -              .. s                i to0X Figure 4.3-1.                                                     Example of Low Oxygen Sponge Zirconium-Lined TubesheII Showing the Zircaloy-Zirconium Interface Prior to Tube Reduction 4.4 SUBTASK lli. 3 IRRADIATION AND EVALUATION (J. R. Thompson, NFSED)

Power history data using the Fuel Performance Analysis and Data Acquisition System (FPADAS)2 will be collected for both the lead test assemblies in Quad Cities Unit 1 and the demonstration fuel planned for Quad Cities Unit 2. The f act that the Quad Cities is a dual unit station controlled by the same process computer allows the data from Units 1 and 2 to be collected on the same magnetic tape. Sof tware modifications are currently being made so that the process computer will provide the power histories from both plants. The new software program will allow the core performance and detailed power history data from each plant to be separated and stored for later use. A4-88

NEDO-24259-A (from GEAP-25163-2) I i ( l , u.,pa+a p3 . . :.=., . , ,

                                                                           .,,.3. ,. s.m.
                                                                                     . . . .        p .c
                                                                                                              ; . '..wn.r
                                                                                                                   ,d ,r, < . *,.,      W<..w

v. .) .,. .. . .*g.~.V,.

                                                                                                                                                                . .. 4 ,.a., , 7.9,.,?;.v:!.;X'
                                                                                                                                                                                 .          , . Vv,..j.. 7.
                                                                                                                                                                                                                                        .1.:?.V..%<.r.

pr . ,: .. .

.V .',..?

                                                , e.                                                                                                                            ,        :* *                                                       [*.
                              ,I-3:p,q.b..'                                                    .,' .*.,,      ?.f . ?;m.$..
                                                                                                                                                              ,k.'            o *.,y q.p.,.
                                                                                                                                                                       ..p,.,**.                   .

w.~,,.. .

                                         . .;.' w .c'y          ;. ,

s

                                                                                    .. sjm%,                            - e.*.. ..*; v..                          n :9.x,r.

n.q)u,t.:.p.p..; ,+. i t m WM!@ tad" ' ., %,.~.

                                 %..'.k."W./a                                                     p..ft:~                                                                                                                                       .l .<f:QD. Gl,:::.%.. C-2.f:
                                                                                                                 .C :;!. . @.A'..y                       Vu: m :::.iiQi                                 nGjW. O.

i . . . r .. w .<. A' p. jy-

                              .e, = .

Y nit n&::i<<.Jt ' Y:.'5. iri'*kUl5,.'. .

                                                                                                                                                                   $?:W e-     %. My$Ty0.yt-::MC    h&,                         r.4;lfy;,.y:                             El.'.I gu.+,c .1,u>.,       gqp,
                                                                                                                 .,          ...-          -                                                                                                     i
                                                ..,w                                                            ng;w n. 3 ,..u f. :. . ,..,.r .1. , .g               .

e.. :,.. g. c,;V.;,.y ..

                                                                                                                                                                                                                                                                 .u. y 7., v ../. ..                                                                                                 e s ,..+ 3,.,                  ,4 v... + e~
                                                                                        .n.
                                                                                                     .                                                                    .                                                          c             . : .
                               -: .,L & ~,o 'blOn
                                               .s-wp ,ps hL/y}..%:          .1
                                                                            ..                                                        s-                    *;Q %;y,. ;.~L-                      .'T                                       ,Q.%s q-g 1

p 'fl.V.v YW_ab &- ;;&,y.&i L. .i. ., ~ g '. .

                                                                                                                                                                       ~*-
                                                                                                                                                                                           . . . .: . L.J".&a.[.s~
                                                                                                                                                                                                         .g.. ,? . .r.         .
                                                                                                                                                                                                                                               .. ,n . .. .

ss< , .

                                                                                                                                                                                                                                                      'j .
                                                                                                                                                                                                                                                                   '                         ,ft' gh
                                                                                   #7*m.',j                                             &*n                               ,,

O. I ' GF,- espw'.&j\, fv , >y. .q. :9. . .aL.

                                                                                                                                                                                                               %?.
                                                                                                                                                                                                               . , .%:p
                                                                                                                                                                                                                                           '.y.U
                                                                                                                                                                                                                                 ?. .A. . . y.;t;,            .            ::';.)i.

s .a" . , .s.g. ,%,

                                                                                                                                                                                                                                       ., ., e. . )-         y
                                                                                                                                       ;y, .pr,yi        A           .3
                                                                                                                                                           .q.%.e p; 1.,' p N . }y # ,
                                                                                                                                                                                                             .                                        5.:,

7. 8. '

m .. g m.sn> 4 ..,s.z..,, . . .. . .

\                                                                                                                                                                                            C t t..,;,-* a .G:<

1 iM. . ,. .7 w. , _.. .

!                                                                                                                                                                                                                        ....o.,

r.er *.. s.

                                                                                                                                                                                                                                       ..s         .1
                                                                                                                                                                                                                                    +-                  +; .

(a) 200x l.

                              .r g,.. . ,.w.r. n,y,p.~' ,.n.;;;

na 1

                                                                                        ,t . o . n>.c..,,+ , .         i .y. e.

m..a.w<u,.:was ny. 4n .....r,.,,..v n..4 ,c., .w 2, 14

                                                                                                                                                                                                                       ,,*. r .a ,s , . . . ~ v .:.g n.h,. <  .

N

                              ;g      u. .+(y - .n           .i             m'.... :i,4s, y. ..m     if *!d Ts.yb,.,r. g , f. ,M..,,M.:.

_ .a .0  : e,< .,,, Q. . . ..q . 4.s.W. . V . Wa.c, ,. ./>3. . m v. A .o....,.,.o g 3 .

                              .s.-..                  u

e. ~ .- . > v y..

m, . . z m:. <v .,

                              %v. ,[ w                      Q.n.      a .~        s 'Q';,.Nn
                                                                               .s...

r.,,'s . .: . fi,%xyd, ;5. .s .M.3.,.,W , t ,-, M:

                                                                                                                                                                                                             ,m.c.,d'q:&94.             ,

M}i.

&yn 'd, 4.s:ty..v, ,. ; .v

                                                                                                                                                                                             . - -                                 c.;, ., t pl} y .y; :. *.; : e :
                              %a,i,,,.              .
                                                                     , . ..n..q 4p@,                y,M;
                                                                                                                            ,.           t i     r 'ye
                                                                                                                                         .y y. %.M w.             ,1!y             y      y;.s.              ;s}E..

y y'y :s.g.. ?}, ,,. ~;

9. . ;.i:

                               ;. n.:
                                                                           '.,@M)~.}                                    ,opy, r                                                                  ,
                                                                                                                                                                                                               .,q.       ,s,- O MP 'qm I

n .s y. ,. s l

n,M. . g.x. W2 . . v .e % ;..pz.n.. m, - c.

                                                                                                                                                                                                                                           .;/g:y.            ,'.q   .
                                                  . .                 ..,u.

.e? w. ll,w.y  :.:v:b,.;;.;;..,n. ~p (;,:Q f,. l 1  %  : , .p, .

y : n..:i. 3l:I ,. y Q,.:i dh..f,k,].Q.K bh ., n;'_,5;.Yg Ni ' ' ,'I

• W. .q..)

                                                                                                                                                                                       ;.Q g;,'m a:;       y,C.Qm  -         .1Q   n,bl;'Q
                                                                                                                                                                                                                                   /1 ,      x:            -
                                                                                                                                                                                                                                                           .Q.

8[

                                                                                                                        .n~^.~O.N                   ..*$?QN..         . ~.f,I*&..$                           , . ' . "'M                 Nk #.ll$W< slp,;
                              &a.Yr ;* ; i u 4..                       ',       &.          ?,':$                Q;??o
                                                                                                                    *..       . <g. . w , .
                                                                                                                                                              ',            ->:                          .,       :n.,,          ,    ,.
                                                                                                                                                                                                                                                          ,                                         i 9.,.., p. 4          .
                                                                                                                                                                                                       . .. ?' q. _~.                 , ,:...6,,    , ..s,,w".m..                        p. . . .
                               ?f             .

5~ . . Q, .' 4; ar 3 ?.,  ;,, , , . a. g.

                                                                                                                                                                                                                                                                                                     )
                                                                                                                                                   ~ .s. W~ , , , r. y-) .,35
                                                                                           ,,,                                                                                                                                                                        .                              i
                                                                                          ,         . .               ., ..                          .                                                                                              . .e ,:.
                               ! g .,                                       t*,           s                       -
                                                                                                                            --.t,                                                  s..,                                                s . 3           s.
                                ;- ',.                                                         'q
                                                                                                   , c.. &      -- ., p' :. . y!*:ls. s ,g o: : '!
                                                      -y _ v,                                                                                                 m, .                    p :..i H, ...-);,

g , . ,

                                                                                                                                                                                                                                               %Q:~' X..3 g4                     -
                                                                                .s -
                                                                 .-r.,4. v. ;,7 .,. m . m                        +

r

                                                                                                                                                  . c ,,

m, ,.' . < w.. c q. +

                                                                                                                   . 4          . , j,.f... ,, , 7,;_ ._:_
                                                                                                                                                                                                                  ,~1 q:.'y,~f. .c<                        ...,s u r. -: r, t - ~i                                   ?           .

g ,

                                                                                                                        . >-                                                                              "L e                   ,,

a .c v w. ; _ ..: s.,. p , . ,' . .- ...e ~ ~

                                                                        ; . 4b _                                             s t. T i N
                               . . , ~ . .a_y3 . x ,.

v. ,f

i. < a . ,',, ;t,,; .

n.

                                                                                                                                                                                                  , 'y ,.,;.. . .' ..,,

y s .+a,~+ J v<.1.e.n , ,W*; p-. m; ,..* e y;' m.:.h... v m s-5.s:s s w-; - I I (b) 200X ,t i l Figure 4.3-2. Electroless Copper Plated on Oxidized Zircaloy, Viewed in Tapered Section. (a) WLM (b) CRD  ; I 6 I h I i i A4-89 I l

l l l l NEDO-24259-A i (from GEAP-25163-2) I

     '.,,        (-
                                                      , .          ;+

• 4 ;.

                                                                                                                                            +
                                                                                                                                                    ... .                               - ~ ,
    <-                       ,.                          ~;                                                          t                                                             ,
                                              *             - 3,                                 ,*,                      , , -
                                                                                                                                                %.1 s                                                                        .
                                                                                                          ..;ws  .,w.=

v' ,., ,P ' n,e$,* y,..

                   .   <..         ,F           ,.
    .,                                                 (                              .
                                                                                                                                            /
                     -    .'    s           +                                                                                                                  ., , , . , ..
    %.              .,                    e.A~.                    ~            .

b;

          #4 s .. -
                     .' W. y w_,..:.:<,             ,. ...,, a,3 .. - O '.e .?,;*

g .e '.M ~ , . * ~. y

g. - -

                                        ~       . ~v s.p      . a..- . ,r               , hr g;,.,f, .                                   .

w, . , >. . . C k kN$ s,,.m, W e 7. o .

                                                             -u . $. y.                                  h$?.c.W..
                                                                                                                ., v s p,yp s.< ,g4, ,, e, , 7.
                                                                                                                                       ,t
                                                                                                                                                                          ., r,y. MMsfe. r. . m. 1 p #..                  .                                              ->            .

Q#p'* W@gm.p y..M5..c .s?&. m*4 < ~. v.'..y.~. qe ' %,0..Q'.)4.W.. N,. } ?.?, ;5 M w .

p. s.~, m . ,,

c. ,, . r.

                                                                                                                                                        -e
                                                                                                                                                                                          .p
                                                                                                                                                                 % : ' < ..p*:

h;',r., n'%._ yQ,w. 3,w,

.~ ," W, .'n,4 .:. ..v..

    $,~        'l. ;i%jV        R.,. :.qi                            .p. . >v.;f.,,s
                                                               $,%qR~~                                           r#.    *Wf.3.
                                                                                             ; ,.~V. (s-; ;. a '~,Y..Q+'s1*:.y;y*.

y. l ' ax

• 7 -f . t. .

7

                 ~:                                                                                                                                        ,

p u.sy gyn . c.s t';ym. x ..yM +p , ,, .. - e, p~ M

                                                                                                                                                               .-..c

4. '..5.: , ,c. i..'.,r<v.

                                                                                                                                                                                                         ~

y~..

                                                                                                                                      ;     ,,   .        <(.~, *.;y n. ,.y.
    .n j;,. y w....w.$ p w
                                                                                                           ,        4         ;     x          ,

v~ .hg 7.+.y.y, e , . . . , . : ,- ~1,... y; w . ...r. s.: .v :::.f w++

                                                                  '.. ? .*,; ...,J'r q ;:,, V .: . .,a.e*,. .O,.'...
       ,%, ,. , . ,1 j 3--', , ,-..4                  , . 3<. %., ... . . , . , , . . ,e g_.,,                            .                           .
                                                                                                                                                                                                         . j.

N.,;,... w. . , g ' ~. <ps >f y m x,. ... ~ p ,~ .

                                                                             .-                . o n. ; ;                                                        . . .
    ..                       y                               . :                                          , ,             :            ^,; ; ,.,'?                           .(.-
    ... 6;..; G 1 ,,r h : A ,,--, y,. l~, ., . .,                                                                                                                         ,t.A.. ,                      . , ,

(a)

                           .+5
                                                                                      .      *                  ~>,,.                             s
                                                                                               - t3 g .3 *,*                                                                   t            -.              ,

f ,' e*. g s j, )

                 * . , ' q
                                                                *,*+,
    *                                                                                                     -              s                                                                         .r              <f
       *

• O' W ,. '?W

   *,* .. . .r. .+
                           .  :% ,; , ,, * , , .s- .'<+1:   .

y. _ < y, . i. . .

2

                                                                                                                                                                          ,,         =
                  -4                                                     r
   ; yo ...,,,,.

Q ' *;, y> h . 3* ' Y, . e,, ,, ,. .~ *' .u: ;o.+ 3 ,'2, -l

                                                         ,7"4 k,.
                                                                                                                                                        ,                                                                                   \
         ~ ,,,                ,,
                                                       '                                                      -             .                           4            a                       +                                              l lh              w                                                e". . m; J W                               s '1 *&* g
   's a+ ** e~

o;,. - ' * *. ?.:

                        .tj' . ,; *,a*
                                                            .s
                                                            .>.:*g.. s +.o--        -

g .<

                                                                                                         %. . /,ye r.,,s..e, n. ', s ,e,J. s ' .,.>,       .,r
                                                                                                                                                                                                   ,,s
                                                                       ,.4 s jw:=                                     '.

vs, . g,4 c 3 _.

                                                                               ,w                           . s*y
                                                                                                                        ~

y

   , ,. 3 4,.                                                                              A, m ;s +, , , , . . . . ; e 7.q .+                                              .~3,              .? , a
    , ,fW                                                                                                                                                  '+','M ,4-4 9i %' ..
                                                                                                                                                                                                 ; M , j A,.." ^,).'?,T.        ' % ' .: ', '

• M;s

                                       ,y y.

b;.

                                                                                                                                                                                         -Q'                         -

y > n,

                       . 4, v.m           .
                                              .-*g           s :.e.   , gg e,st      s ,. -

o, % s e.g*::= , e w k s ?; w e t b ... h '!!k V ; g k$ h'h :..55G.& M,g; z%.o gd, o grus*w/%& R&:_s.7)

                                                                                                                                                                  , 4 .,

.~,.. pm . y*rse & _,k: r.W.:w.w 1A:

                . ~.m - :s M.c.kiu/..4B              .. 1                                                                                                              .%M~s~>                                        M .!J m:.

p

   .. p %,.c.,a,d
                                    . , .                        Ar3-y    4 +Y,y:- 2y,V.&  s                            e @1 n a.u t.#,;.t a                                             ?~ r,,,n~

c4% - i pi,^t f: .y>,. : MM v4 Js QQ: ~ ; .8*)PG.' g,,4; v 9 y~Jw,s*&-

                                                                                              <f,Q;.7:p 4                     -
                                                                                                                                                           %Q<

s- Q-~M;j. ~sp.Qs

                                                                                                                                                                                                                          ,,y, N. u.v'g     l wi&m&*g,&

R s.e &:!WS fQd 4 I f t l w k& aw &;..a s . - (b) Figure 4.3-3. Same as Figure 4.3-2 at 1000x 1 1 A4-90

NEDO-24259-A (from GEAP-25163-2) l l wm e '. - .

                                                                                       $A,             ,

N

• me

                                                                                                                              .3 (a)                                                  5000X
                                                                        " ,-  *"y y.                   i N"*

l

                         ,.    -4j,, ,                 ,4.'                          fM. .                 '.            g 

7

                             ;  f            n                                .
                                                                                     .' p,W
                                                  *'           ~                          '                                                '

r - i , k+

s. g .. - . J; *

• b y

N < - y'< P' , 4' 's i ' K .>

                                       #              t-                                ,.               ,

(b) 5000X Figure 4.3-4. Scanning Electron Micrographs of Copper Surfaces Electroless Plated on Oxidized Zircaloy. (a) WLM (b) CRD I A4-91

  +ks s                  . . . . - , -

TEST TARGET (MT-3) s%o l.0 's en Baa

                                  - [ @ ILE i,1

[m lilM .,

                                               .8 1.25         l.4    1.6

'/ = g" #

  #4 '                                               +4%

• %f$/ n,,

                                                    'kWO e.y

kh!/

   +/ \\\\      IMAGE EVAi.UATION TEST TARGET (MT-3)
                                               %4NNN\  !

H I.0 'flm en y l8 lM4 1.l [m HE )

                                       '8 l.25  l 1.4     1.6 I
 /         e                6"                   >
    *r&%                                       +<$+
   " *~      //   .                       ..

N{k$b

                                **f

NEDO-24259-A (from GEAP-25163-2)

                                                                                                                          ^^

WThif*is?p.. 'K.~~ '3 dryC?#4 . qs *% , T ,,

                                  .                         g9:

f4[y7g<I [f m *

                                                                                                       <p
                                                                                                                 ;:h ', p.7 s x         ~

ZlRCALOY

                                                                      #fh.i:; }                            l/ +                          +, *
                                                                      ~s-QA&f      J+.;,& G -
                                                                                                               s-           '
                                                                                                                   .,,,,.        y,7 4. g ffs.
                                                                      ' %f                                                             ,fs                          '
                                                                             ,          1::  <$                      ~'.
                                                                                                                       <             .z : ., L" l                        w            Kyl                            {
                                                                                                                             .-s.... s,                             ,

4-. yghs}34 t

                                                                                          /
                                                                                                                           <:41yf  s p)}

7 34. :gt

                                                                                               - y                                ~ QQf ' #

re (a)

                                                                                             #dh        COPPER                         5000X                        1 1

COPPER

                                                                                               <4
                                                                                                  *4

_ g. I g: ~,, lp p',T3:}g,9ek

                                                                                              * '?

n mugg.gr@s

                                                         +   2 G .M +             .. p '4:
                                                                                             %                    ' a 3_7         'O                 ZlRCALOY
                                                      ~ U .Y                     '
                                                                                                              , T'b') ; l-fr]"-_._
                                                           ' fks:ftq*,*f'p.;).-   f                         *
                                                                                                                        ;q :-f )
                                                   " lNA;'WTh                                          + ,;[

i. }V.E ' 'MlA )

                                                      - :3sy; y kai$$b                                     .ai,laurauwlNb                                                       l (b)                                              5000X Figure 4.3 5. Copper Electroless Plated on Oxidized Zircaloy Viewed on Polished Cross Sectioned and Etched. (a) WLM (b) CRD A4-92

l NEDO-24259-A (from GEAP-25163-2) IMMA$ g

                            "$$$$                    (e)                   5000X 3#       'J    '
                                                 ,* ,8e N,'!d  ],.

g g1:p=fW},, w.. (?**.,apg;Ul}.h$)l.V,.

                                 ,$!?!

Jh. ,, c. ,.,,t,.,.u,[,.kT$' ~ tjrf.M ifQ *:ji, (b) 5000X Figure 4.3-6. Zircaloy Tubing Surfaces After Removal of Copper in Dilute aq. HNO,. (a) WLM (b) CRD A4-93

NEDO-24259-A (from GEAP-25163-2) ACKNOWLEDGEMENTS The contributing authors of Subsection 4.3 gratefully acknowledge the help of their colleagues: J. C. Madore of WMD for ultrasonic test development C. A. McKinney of WMD for planning and execution of tube reduction R. S. Moore of WMD for invaluable guidance on barrier fabrication techniques R. E. Strine of WMD for assisting with quality assurance C. Robertson and N. Lewis of CRD for doing the scanning electron micrographs used in this report. A. S. Holik, J. M. Grande and C. Rodd of CRD for metallography of the copper plated Zircaloy F 4 4

                                                    .A4-94

NEDO-26259-A (from GEAP-25163-2)

5. TASKIV LEAD TEST ASSEMBLIES (J. R. Thompson, NFSED)  ;

I Irradiation continues on the barrier lead test assemblies (LTA's) at Quad Cities Unit 1. Operating data is being collected and stored on magnetic tapes. The exposure through December 1979 is approximately 6.5 mwd /kg U. The purpose of these assemblies is to precede the large scale demonstration fuel assembliet ,vith 3ignifi-cant exposures. (See Subtask 111.3.) The LTA bundles will be inspected during the f all 1980 outage. (Shutdow? is tentatively scheduled for October 15,1980 for 15 weeks.) ACKNOWLEDGEMENTS The help of the following people is gratefully acknowledged by the author of Section 5: W. A. Wong of NFSED for help in compiling and computing the power history data C. Brown of the Quad Cities Nuclear Power Statiori, Commonwealth Edison Company for his cooperation and assistance in collecting the operating history data. REFERENCES

1. Demonstration of Fuel Resistant to Pellet-Cladding Interaction, PHASE 2 First Semiannual Report, January-June 1979, compiled by H. S. Rosenbaum, GEAP 25163-1, August 1979.

2. Demonstration of Fuel Resistant to Pellet Cladding Interaction, PHASE 1 Final Report, compiled by H. S. Rosenbaum, GEAP-23773 2, March 1979.

3. Demonstration of Fuel Resistant to Pellet-Cladding Interaction, Second Semiannual Report January-June 1978, compiled by H. S. Rosenbaum, GEAP 23773-1, September 1978.

4. Demonstration of Fuel Resistant to Pellet-Cladding interaction, First Semiannual Report, July-December,1977, compiled by H. S. Rosenbaum, GEAP-23773, February 1978.

5. S. R. Specker, L E. Fennern, R. E. Brown, K. L Stark, and R. L Crowther,"The BWR Control Cell Core Im.

proved Des:gn", Trans. Amer. Nucl. Soc., 30 (1978) 336.

6. B. Cox, " Oxidation of Zirconium and its Alloys", Advances in Corrosion Science and Technology,5 (1976) 173

7. R. S. Forsyth, W. H. Blackadder, K. Malen and G. F dnnberg," Fission Product Release to Loop Water from Operating Intentionally Defected Fuel", paper pr64nted 31lAEA Specialists Meeting on Defected Fuel Parformance, Chalk River, Ontario, Canada, September 1979.

8. S.Junkrans and O. Vsrnild," ASEA ATOM Research on PCl", Proceedings of Topical Meeting on Water Reactor Fuel Performance, St. Charles, Ill., May 1977.

9. F. Garzarolli, R. Manzel, M. Peehs and H. Stehle,"KWU Observations and Hypothesis of PCI Failures",

paper presented at IAEA Specialists Meeting on PCI, Vienna, Austria, June 1977.

10. H. Kleykamp,"The Chemical State of LWR High Power Fuel Rods under Irradiation", Karlsruhe Nuclear Rssearch Center Report No. 2696, Jan.1979 (in German).

11. D. H. Locke,"The Behavior of Defective Reactor Fuel", Nucl. Eng. and Design 21, 318 (1972).

A4 45/A4-96

NEDO-24259-A (from GEAP-25163-2) DISTRIBUTION i U.S. DOE Distribution (200) M. D. Freshley (3) Category UC-78 Battelle-Pacific Northwest Laboratory U.S. Department of Energy Richland, WA 99352 Technical information Center P.O. Box 62 F. E. Gelhaus Oak Ridge, RN 37830 Electric Power Research Inst. P.O. Box 10412 J. S. Armijo Palo Alto, CA 94303 General Electric Co. Nuclear Energy Division D. J. Groetch 175 Curtner Avenue Knolls Atomic Power Laboratory San Jose, CA 95125 Box 1072

  .                                                    Schenectady, NY 12301 D. E. Bessette Advisory Comrnittee on Reactor                     R. M. Grube Safeguards                                     Yankee Atomic Electric Co.

U.S. Nuclear Regulatory Commission 20 Turnpike Road 1717 H. Street NW Westboro, MA 01581 Washington, DC 20555 John Hallam Gordon Bond Nuclear Services Corp. GPU Service Corp.: 1700 Dell Avenue 260 Cherry Hill Road Campbell, CA 95008 Parsippany, NJ 07054 C.R.Hann F. W. Buckman Battelle-Pacific Northwest Laboratory Consumers Power Company Richland, WA 99352 1945 Parnall Road Jackson, MI 4920t W. R. Harris Rand Corporation J. P. Cagnetta 1700 Main Street Northeast Utilities Service Co. Santa Monica, CA 90406 P.O. Box 270 HartIord, CT 06101 J. Horak Oak Ridge National Laboratory E. L Courtright P.O. Box X Battelle Pacific Northwest Laboratory Oak Ridge TN 37830 Richland, WA 99352 i William V. Johnston C. E. Crouthamel Chief, Fuel Behavior Research Branch Exxon Nuclear Company,Inc. Division of Reactor Safety Research Richland, WA 99352 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 G. F. Daebeler Philadelphia Electric Co. W. M. Kief er (6) 2301 Market Street Commonwealth Edison Company P.O. Box 8699 P.O. Box 767 Philadelphia, PA 19101 Chicago, IL 06090 R. N. Duncan J. Korthever Combustion Engineering,Inc. Duke Power Company 1000 Prospect Hill Road P.O. Box 2178 Windsor, CT 06095 Charlotte, NC 28342 A4-97

NEDO-24259-A (from GEAP-25163-2) P. M. Lang (3) R. R. O'Laughlin Nuclear Reactor Programs Branch Public Service Indiana Division of Nuclear Power Development 1000 East Main Street U.S. Dept. of Energy Plainfield, IN 46168 Mail Stop B-107 Washington. D.C. 20545 R. Omberg Hanford Engineering Development D. L Larkin Laboratory Washington Public Power Supply System P.O. Box 1970 P.O. Box 968 Richland, WA 99352 Richland, WA 99352 B. A. Pasternak M. L Lee Booz-Allen Applied Research Consolidated Edison Company 4330 East. West Highway of New York Bethesda, MD 20014 4 trying Place New York, NY 10003 J. T. A. Roberts Electric Power Research Inst. Kashmiri Mahna P.O. Box 10412 Public Service Electric Palo Alio, CA 94303 and Gas Co. 80 Park Place T. Row Newark, NJ 07101 Oak Ridge National Laboratory P.O. Box X Tony Mansell Oak Cidge, TN 37830 Arkansas Power & Light r P.O. Box 551 Little Rock, AK 72203 H. W. Schadler, Manager Metallurgy Laboratory R. O. Meyer General Electric Company Attn: M. Tokar Research and Development Center Reactor Fuels Section P.O. Box 8 Division of Systems Safety Schenectady, NY 12301 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 T.Snead Duke Power Company R. S. Miller P.O. Box 2178 Westinghouse Electric Corp. Charlotte, NC 28342 Nuclear Fuel Division Box 355 Howard Sobel Pittsburgh, PA 15230 American Electric Power Service Corp. Nuclear Materials and Fuel R. J. Mullin Management Section Tennessee Valley Authority 2 Broadway 1410 Commerce Union Bank Bldg. New York, NY 10004 Chattanooga, TN 37402 G. Sofer D. R. O'Boyle Exxon Nuclear Company, Inc. Commonwealth Edison Co. Richland, WA 99352 P.O. Box 767 Chicago, IL 60690 1. Spiewak Oak Ridge National Laboratory P.O. Box X Oak Ridge, TN 37830 - A4-98

EEDO-24259-A (from GEAP-25163-2) W. J. Tunney E. Straker Science Applications,Inc. Long Island Lighting Co. 8400 Westpark Drive 175 E. Old Country Road Hicksville, NY 11801 McLean, VA 22101 D. B. Wehmeyer J. R. Tomonto Florida Power & Light Co. Detroit Edison Co. P.O. Box 013100 2000 Se(ond Avenue Miami, FL 33101 Detroit, 'l48226 J. Tulenko W. A. We...teich Bettis Atomic Power Laboratory Babcock & Wilcox Co. Nuclear Power Generation Div. Box 79 P.O. Box 1260 West Mifflin, PA 15122 Lynchburg, VA 24505 K. Woods Exxon Nuclear Company,Inc. Richland, WA 99352 I 'l A4-99/A4-100

  -        m    -- __ __--._ __- --            _ - . _ _ _ _ _ _ _ _                           .

PllASE 2 - KEY MILESTONES / DECISIONS s MILESTONE TARGET DATE INFORMATION TO SUPPORT DECISION START IRRADIATION OF LTA'S FEB 79 - SRP RAMP TESTS TO ~9 GWo/MT SELECT REMEDY FOR DEMONSTRATION JAN 80 - SRP RAMP TESTS TO ~15 GWo/MT

                                                              - ALL PROGRAM DATA (LOCA, ,,,)

START FABRICATION OF CLADDING OCT 80 - LICENSING OF BARRIER FUEL BY NRC

                                                               - LABORATORY DATA ON DESIGN PARAMETERS
                                                               - DEFECTED FUEL TESTS                            g
 >                                                                                                              f I START FUEL ROD AND BUNDLE FABRICATION        APR 81         - COMPLETION OF NUCLEAR DE31GN                   s
                                                               - CORE LICENSE SUBMITTAL                         y
                                                               - FIRST INTERIM EXAM OF LTA's START IRRADIATION OF DEMO FUEL               DEC 81             DAMP TEST DATA AT ~20 GWo/MT FIRST DEMONSTRATION RAMP                     JAN 83         - SECOND INTERIM EXAM OF LTA'S AT
                                                                  ~15 GWo/MT
                                                               - RAMP TEST DATA AT $26 GWo/MT                     [

k SECOND DEMONSTRATION RAMP SEP 84 - RAMP TESTS ON SPONGE ZR-LINER g AT ~15 GWo/MT $;

                                                                - THIRD INTERIM EXAM OF LTA's AT
                                                                   ~22 GWo/MT

1 i SCHEDULE FOR BARRIER FUEL DEMONSTRATION PHASE 2 79 80 81 Il l1I l1ill 1 l l l1iliill 6 Il l1 lll 1 l6i OUAD CITIES 1 - k%'f OUAD CITIES 2 [k% k% h e E 5 0 8 mwd /kg U j. LTA IRRADIATION l l ll (BUNDLE AVERAGE) DEMONSTRATION IRRADIATION 001% 5 A i

SCHEDULE FOR BARRIER FUEL DEMONSTRATION PHASE 2 9 81 82 83 84 Ill1Ill 1lI I I1l11ll l l61 1l l1 l l6l ll l iljiiji i jii OUAD CITIES 1 g(( { QUAD CITIES 2 [q NN g?) 6 g 7 a 3-M 8 i b 1 L 15 22 mwd /kg U 1 , LTA 1RRADIATION ' (BUNDLE AVERAGE) 9 DEMONSTRATION , IRR ADI ATION g'

                                                                                  '                         i   b DEMONSTRATION RAMPS I APPROX.)

007 % 58 w

NEDO-24259-A SCHEDULE FOR GENERIC APPROVAL NRC SUBMITTAL MAY 1980 APPROVAL REQUIRED OCTOBER 1980 PLANT / CYCLE UNIQUE SCHEDULE BEGINS NOVEMBER 1980 I JC:JLK/13f40 3/25/80 AS-4

i NED0-24259-A APPENDIX B ADDITIONAL INFORMATION IN RESPONSE TO REQUEST 231.2 e i I-1. l-p ) B-1

NED0-24259-A l GENERAL h ELECTRIC NUCLEAR POWER SYSTEMS DIVISION GENERAL ELECTRIC COMPANY,175 CURTNER AVE., SAN JOSE. CALIFORNIA 95125 MC 682, (408) 925-3344 REE-062-80 MFN-]70-80 October 2, 1980 U. S. Nuclear Regulatory Commission Division of Licensing Washington D.C. 20555 Attention: Robert L. Tedesco Assistant Director for Licensing Gentlemen:

SUBJECT:

ADDITIONAL INFORMATION ON NE00-24259, " GENERIC INFORMATION FOR BARRIER FUEL DEMONSTRATION BUNDLE LICENSING" Attached is additional information in response to request 231.2 regarding the document NE00-24259. During telephone conversations with members of the NRC staff, General Electric was informed that additional information on responses forwarded with the letter of September 11, 1980 was required. . Based on conversations, General Electric believes that the attached ' information clarifies the previous responses and allows rapid approval of the document for the licensing of the barrier fuel demor,tration.  ! l General Electric would like to reiterate that the demonstration plans do not call for subjecting any of the fuel to conditions which exceed the limitations of the technical specifications and that none of the fuel will be subjected to conditions where, from the experimental evidence, any failures would be expected. A technical specification change may be requested by the plant operator because of test uncertainties. As stated in the letter of Septenber 11, timely implementation of the barrier fuel demonstration projact requires that hardware manufacture begin in October 1980. Based on conversations, General Electric believes that the additional information attached provides all the information required and looks forward the approval of NED0-24259 by October 7, 1980. Very truly yours,

            /

R. E. Enge , Manager Fuel & Services Licensing Safety & Licensing Operation REE:rm/2007 cc: M. Tokar, NRC R. O. Meyer, NRC L. S. Rubenstein, NRC R. B. Bevan, Jr. , NRC W. Johnston, NRC L. S. Gifford B-2

NEDO-24259-A

a. On-Line Failure Detection The current steam jet air ejector monitoring system is an on-line gamma-ray detection system that reads the dose rate and can detect

     ~

changes in gamma-ray intensity within 2-5 minutes of changes in the core offgas (e.g. fuel failures). Inferences regarding the numbers of fuel rods failed in any time increment are now made by isotopic analyses of gas and coolant water samples. Thus, the gamma-ray detector near the steam jet air ejector can be used to initiate a sampling sequence which can then yield an estimate of numbers of failed fuel rods. Relatively small changes in core offgas are reliably seen in the 2-5 minute interval which can be f indicative of fuel failures. Presently, there is no direct cal-ibration to link total gamma-ray intensity with the number of failed fuel rods; however, experience has shown that this system is a sensitive indicator of fuel failure. Currently, the offgas samples indicate a total activity of s90,000 p Ci/s. It is expected that at the time of the first demonstration ramp, near the end of Cycle 6, the activity will be ~55,000 p Ci/s. By suitable sampling of offgas and coolant water, it is conservatively estimated that failure of less than 10 f al rods could be rapidly detected. The demonstration will involve a step-wise movement of a control blade in a amp cell; each movement will expose 1.5 ft. of the four bundles in e ramp cell. It is the intention of GE that the operating I n allow for evaluation of the number of failed fuel rod.i (if any) caused by each incremental movement of each ramp cell control blade. However, as was stated in the letter of September 11, the actual operating plan has yet to be developed pending approval by the NRC of the generic license, NED0-24259. That operating plan will be developed jointly by GE and the utility. General Electric has limited experience with other on-line fuel failure detection systems (e.g. Krypton-85 detectors). These systems have yet to be demonstrated as being reliable and effective indicaters of fuel failures. It is the belief of General Electric that the present on-line detection system is a demonstrated sensitive, reliable, and timely detector of fuel failures. e

b. Post-Irradiation Surveillance At refueling outages during the demonstration GE will recommend to the utility that all barrier fuel assemblies which were ramped in that cycle be sipped along with any buffer fuel assemblies which are scheduled to be returned to the core for additional irradiation.

In the event that sipping results indicate that barrier fuel has e failed, t'4 core management plan (i.e. the operating plan) will be d reevaluated. 1 B-3 i

NEDO-24259-A Examinations directed toward detecting incipient fuel failures are not part of the current work scope for the demonstration fr . However, it is the intention of GE to recommend examinatior discharged demonstration fuel to assess its condition, inc h ng the possible presence of incipient defects. A very detailea examination of the two Zr-liner lead test assemblies which are currently in Quad Cities Unit 1 is within the work scope. The first interim examination of those fuel bundles at a bundle average burn up of $12 GWd/MT has been completed very recently, and results are very favorable. The nondestructive examination of these lead bundles includes ultrasonic and eddy current tests of fuel rods which have t m fully pre-characterized prior to irrad-iation.

c. PCI Failure Prediction In the letter of September 11, the ramp test data for reference (nonbarrier) fuel and for Zr-liner barrier fuel were shown in Attachment A2. Those data are from the controlled power ramp tests conducted in a test reactor (either the GE Test Reactor at Vallecitos or the R-2 reactor at Studsvik in Sweden). The data labeled CC are a thin-walled test fuel designed to accelerate and exacerbate the PCI effect so that data could be obtained in a relatively short time. The data indicated by SRP (the segmented rod prooram) are for fuel rods which were irradiated at low power in a commercial BWR to the indicated burn up and subsequently power ramp tested in a test reactor. The lower curve on Figure A2-1 defines the failure threshold for reference (i.e. , conventional) fuel; that is, no failures are observed below this curve in this experiment. The upper curve detines the range for 100 percent failure of reference fuel. These data will be updated as additional tests are done.

From this data base the risk to the demonstration fuel can be 1 assessed directly. The risk to nonbarrier fuel in the core is assessed by use of both these data (Attachment A2-1) and the total BWR experience with 8x8 fuel. All power changes to be recommended for the demonstration will have been tested previously in a test reactor with '"4 of equivalent (or higher) burn up. The demon-stration will be within the range of burn up and power change of the data base. Thus, GE will recommend no operations in the demonstration for which test data would indicate a measurable risk of fuel failure. These test data are available to the NRC. The demonstration ramps are designed so that the fuel in the ramp cells is ramped to power levels above the threshold curve where failure would be expected if the fuel in those beadles were not resistant to PCI. The final core nuclear design is still in progress, and the exact ramps will depend on the core specific l situction at the time of ramping. l l B-m .}}