ML20085F141

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Change Request 23 to License DPR-4 Re Test Fuel Subassemblies
ML20085F141
Person / Time
Site: Saxton File:GPU Nuclear icon.png
Issue date: 06/22/1966
From: Neidig R
SAXTON NUCLEAR EXPERIMENTAL CORP.
To:
Shared Package
ML20083L048 List: ... further results
References
FOIA-91-17 1784, NUDOCS 9110220059
Download: ML20085F141 (5)
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SAXTON IfJCLEAR EXPERIMENTAL CJ1P0HiiTION DOCKET UO. 50-146 '

LICENSE DPR-4 CHANGE RIINEST NO. 23

1. Applicant hereby sutnits Change Request No. 23 in corpliance with paragraph 3B of License DPR-4 for change of the Technical Snecifications to be authorized by the Connission as provided in 10 CFR 50,59.

SAXTGi NUCLEAR EXPERIMDJTAL CORPORATION BY /s/ R. E. Neidig President i

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ATTFST:

/s/ R. E. Sypher Secretary (S E A L) 22nd day of June , 1966.

. Sworn and subscribed to before me this

/s/ Martin A. Kohr Notary Public

(S E A L) Muhlenberg Township, Berks County y, , y, N

- Ny Commission Expires February b,1970

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Docket No. 50-146 DPR-4 l Technical Specification {

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- Change Request No. 23 Page 1 of 4 Pages l l

1) DESCRIPTION OF CHANGE 1

In Supplement No. 1 to Technical Specifications, add the following Test  ;

Fuel Assembly to ltem F.2. l I

i Test Fuel Assemblv xiv f

One 9-rod subassemb3y shall have the four corner rods and the center rod '

clad with type 304 stainless steel having a nominal thickness of 15 mils and shall contain uranium dioxide (UO2) pellets enriched to 5.7% U-235, having a previous irradiation exposure of approximately 4250 MWD /MTU.

Two of the remaining rods shall be clad with Zircaloy-4 having a nominal thickness of 23.5 mils and shall contain uranium dioxide (UO 2 ) pellets unifomly enriched to 17.4% U-235 and shall be internally pressurized to produce maximum operating stresses of approximately 21,730 psi, having The a previous irradiation exposure of approximately 1900 )fdD/MTU.

renaining two rods shall be clad with Zircaloy-4 having a nominal thickness of 23.5 nils and eacn shall contain a series of 13 Zircaloy-4 capsules. Each capsule shall contain a Zirconium alloy test specianen.

The Zirconium alloy test specimens consist of portions of 0.016 inches thick grid strap material which is spring loaded within the capsule.

Some of the specimens are actual spring fingers of an advanced fuel rod This grid design and some are materials test strips fomed into an arc.

test subassembly may be operated only in a peripheral core location while containing the 17.4% enriched fuel rods.

2) PURPOSE OF CHANGE The purpose of this change is to pomit the insertion of test fuel assembly xiv into the reactor. The scope of this experiment involves modification of a 9-rod subassmbly previously inserted into the reactor.

The objective of this experiment is to provide infomation on the in-pile perfomance of zirconium alloy test specimens subjected to combined themal and radiation fluxes, with particular enphasis on the amount of stress relaxation experienced with the specimens loaded to simulate conditions which would be present in a fuel assmbly sprin6 clip.

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l Docket No. 50-146 l DPR-L Technical Specification q - Change Request No. 23

+g Page 2 of h Pages tg, 4

3) SAFETY CONSIDERATIONS The design characteristics of the two rods containing the capsules and zirconium alloy test specimens are given in Table I. Two two rods are identical in design, material, quality control, and assembly to a l

standard fuel rod. The atmosphere within each rod will be helium under l one atmosphere pressure at roca temperature.

The thirteen Zircaloy-6 capsules contained in each of the above rode, are attached end-to-end by means of a threaded joint. The string of capsules is in turn attached to the top end plug of the rod and is suspended in the rod with a 0.375 inch nominal gap at the bottom end to accomodate tolerance accumulations and slight differential thermalEach

! expansion from differences in cladcontained and capsule temperatures.

in a special machined cavity zirconium alloy test specimen '.s l in the capsule which subjects the test specimen +n a specified pre-load and deflection. Chemical analyses, number and ty,e of each specimen

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is given in Table II. Stainless steel spring pins are used to secure j

each specimen in its capsule and to lock the threads joining the capsules in order to secure the parts during assembly and remote disassembly operations. The pins are installed with an interference fit in the capsules.

The assembly consisting of the top end plug and capsule string is made an integral part of the rod by welding the end plug to the rod cladding.

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' Thus the primary containment for the capsules and test specimens is provided by the rod cladding. The small diametral clearance (22 mils) l between the capsules and the I.D. of the cladding will prevent the stainless steel pins and test spectmens from being dislodged during the in-pile test. The temperature rise, due to gamma heating in the rods, l

l is calculated to be 39-78oF and the cladding temperature will be Therefore, the stresses approximately the same as the reactor coolant.

i in the cladding during operation will be no more severe than those in a fuel rod, and the structural integrity of the rod will be maintained.

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4 Docket No. 50-146 DPR-4 Technical Specification

  • Change Request No. 23 Paga 1 of k Pages The capsules and rod cladding are made of Zircaloy-4. Those capsules which contain 2r-2-3Nb test specimens are provided with space to accomodate and differential themal expansion of the two materials.

Thus, differential themal expansion does not present a stress problan in this experiment. Dosimetry for this experiment will consist of neasurement of the Fe-54 (n,p) Mn-54 reaction in the test specimens and capsules at the end of the experiment. Themal Hydraulics and Nuclear Design calculations show that this experiment will have no adverse effects on core perfomance and will not introduce any hazards into the operation of the reactor.

4) HEALTH AND SAF_ET_Y y

It is our opinion that the health and safety of the public vill not be endangered by this change.

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Docket No. 50-146

-DPR-4 Technical Specification Change Request No. 23 Page k of A Pages TABLE I Rod Design Characteristics Rod O.D.

= 0.391 inches Rod I.D. = 0.343 inches Vall Thickness = 0.024 inches Capsule 0.D. = 0.321 inches TABLE II Description and Materials Stress-Relaxation Experinent k

Description of Test Snecimen Material Arc-Type Zr-2-1/2Nb (Annealed)

Arc-Type Zr-2-1/2Nb (Heat Treated)

Arc-Type Zr-4 Spring Fingers Zr2-1/2!3b

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