ML20085C809

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Amend 10,Suppl 1 to Application for Amend to License DPR-4, Revising Safeguards Rept for Phase I of 5-yr R&D Program
ML20085C809
Person / Time
Site: Saxton File:GPU Nuclear icon.png
Issue date: 04/10/1962
From: Neidig R
SAXTON NUCLEAR EXPERIMENTAL CORP.
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ML20083L048 List: ... further results
References
FOIA-91-17 NUDOCS 9110150020
Download: ML20085C809 (5)
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-g SAXTOU NUCLEAR EXPERDCUTAL CORPORATION Application for Reactor Construction Permit and Operating License , nA J'

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Docket No. 50-lh6 Amendment No. 10 - Supplement No. 1 The following corrections, changes and supplemental information pertains to the Safeguards Report for Phase 1 of the Saxton Nuclear Experimental Corporation's five-year research and development program submitted with Amendment No.10 to the Saxton Application of January 5, 1962.

I. Typographical Errors Page 12 - first aquation should bei 2

kdQ =

1/h ha ,

gljg 77

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Page hl - Unit in Table h for the pressure coefficient of reactivity should be "k/ psi" instead of "k/0F."

Page h6 - Unit in Table 5 for the pressure coefficient of reactivity should also be "k/psin instead of "k/0F."

- II. Changes Page lh - Delete the last sentence of the first paragraph and replace with the following sentences:

"If this does not indicate the unexplained reactivity loss limit to be reached, it may be concluded that the at-power measurements were the recult of other factors, inaccuracies, or reversible effects. The plant would then be returned to normal operating conditions in a stepwise fashion while an endeavor would be made to determine where the unexplained reactivity loss appears. As a final check, the boron will be removed from the system and the at-power reactivity will 4 be measured."

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c l ~2-Page 22 - Paragraph (a) under " Procedures" should be deleted and replacod with the following:

"(a) Stepwise Approach to Full Chemical Shim Operation with Uniform Core The objective of these tests is to determine the behavior of the reactor with chemical shim control. These tests will be carried out at a core inlet temperature not in excess of $E0oF. The boron concentration will be increased in a slow stepwise fashion until essentially all the excesn reactivity is controlled by soluble boron poison (full chemical shim at this point implies a small amount of control left in the rods). It is expected that a minimum of a few days will be spent at each boron level and that the results at each boron level will be examined before proceeding to the next level."

  • III. Supplenental Information
1. At the time the hazards analysis for Phase I of the experimental program was written, the metallographic examination of the control rod specimens in the in-pile loop operated for the Yankee Research and Developnent Program had not been completed. The results from this post irradiation examination of the WCAP-14 silver-indium-

' cadmium corrosion specimens are now available and have been reported in WCAP-3327, The Yankee In-pile Loop Irradiation Test Terminal Report.

The results of this examination are

a. No galvanic attack was noticed between the Zircaloy-2, stainless steel, silver-indium-cadmium or nickel plate.
b. There was a separation between the nickel plate and the control -

rod specimen. It is believed that this occurred during the loss of coolant accidents. In addition, it is believed _that the bond was poor due to improper diffusion heat treatment.

An improved heat treatment was used for the production of Iankee and Saxton control rods,

c. Even though tia nickel plate deformed severely, the-silver-indium-cadmium remained protected.

This loop was in operation only 76 days and experienced several loss of coolant accidents. The specimens were held in the RfR canal for six months before examinations. The corrosion rates therefore probably are not typical of those to be expected under normal reactor operation.

2. On page 7, next to last paragraph, it is stated that the K-boric acid system exhibits retrograde solubility. This statement was based on experiments where KOH-boric acid systems were heated in

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-3 ouarte tubes, f.s the tenperature was incressed, a cloudy precipitate una observed. The temperature at which this occurred varied with the potasslun conccr,tration. The cloudy precipitates ucrc escribed to potassi m mctaborate. The vials have been, retainud for about a yeer at rocu tcaporature without any cign of resolution. This behavior is not indicative of potassium met; borate since this compound is very soluble at roon temper-ature. Some vials have now been broken and the precipitates renoved and analy'.ed. The spectroa;raphic analysis indicates the precipitate to be a cumulex potassium borosilicate. It thus appears that,what was observed was a reaction with the quartz container. The reaction is probably pH dependent and hence the temperature at which it is observed is dependetal, on the potassium concentration.

As pointed out previously, in autoclave experiments with LiOH-boric systems with high lithium concentrations, glassy precipitates have been observed at the conclusion of the experiment. No such precipitate has over been observed in KOH-boric acid systems.

This indicates either no retrot;rade solubility for the K-boric acid systems or relatively rapid resolution of the precipitate.

In view of the revised data from the quartz vial tests, there does not appear to be any evidence supporting retrograde solubility.

3. The determination of the unexplained reactivity loss (see page 13, last paragraph) may be considered as made up cf three parts:
a. At-Power I: valuation These evaluations will bo based on measurement of the coolant temperature, boron concentration, rod position, power output and integrated power output. For each period of such operation, frequent computations will be made. The reactivity measured prior to chemical shim operation will be taken as the base line

, for the initial chemical shim period. An uncertainty will be

, assigned to the evaluation as a function of integrated power output. If the unexplained reactivity loss, including the calculation uncertainty, approaches the limit, the measure-ments described in b.and c.below will be made. After the revised base-line reactivity is determined (see below)_ the next period of power operation will compute changes from +Ms

, point. Successive periods of chemical shim operat. ion will use successively revised base 11nes.

b. Deternination of Unexplained Reactivity Loss Due to Irreversible or Very Slowly Reversible Effects This determination will be based apon periodic measurements of the all-rods-out boron concentration at zero power.

Appropriate corrections for burnup will be made- and the unexplained reactivity determined. To unambiguously obtain the burnup correction over long periods of time, the reactor will periodically be operated without boron. The all-rods-out boron concentration will be determined before and after such

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l -h-l operation. In addition, the reactor trill be operated without boron uhenever the computations based on all-rods-out neasure-nents indicate the unexplained reactivity limit to be approached.

The initial part of this operation will allow any slowly reversible changes to take place and the latter part will I allow the burnup correction to be determined.

1 After the redetermination of the effect of burnup, a new base-I linc reactivity will be established and the total unexplained react $vity loss recomputed (including.the uncertainty).

! If any irreversible or slowly reversible changes are observed, an effort will be made to determine whether the reactivity so found can be released from the core. The reactor will be l cycled, by varying such things as power, temperature and t

pressure, to see if any such cycling can dislodge 'the poison.

c. Dctcrmination cf Reversible Unexplained Reactivity Loss After determination of the magnitude of any irreversible or slowly reversible effects by the procedures described in b, any remaining unexplained reactivity loss must be ascribed to inaccuracies or power reversible effects. The reactivity at zero power determined in a.will be used as a base from which to determine whether power reversible effects are occurring.

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The change in reactivity with power will be measured at normal operating temperatures as well as at a somewhat lower temper-

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' ature so that any effect due to nucleate boiling can be ascertained. In addition, the change of reactivity with power in the absence of boron would be measured again. By comparison of these values any unexplained reversible reactivity loss will be determined. If changes in reactivity with power cre in agreement for the three measurements, it may be concluded that l

there is no power reversible effect.

h. The specially enriched assembly and subassemblies, described in 3 on page 21, will be placed in the central location of the core. .

Mechanically, the assembly and subassemblies will be essentially

! identical to the assembly and subassembly-originally placed in l this core position. The specially enriched units will contain the same instrumentation as the initial units. In addition, it is planned that the first subassembly will contain one tungsten-rhenium thermocouple located in the fuel for measurement of center of fuel temperature.

! 5. The Zircaloy subassembly called for in(c)on page 23 will have the L

l same external dimensions as a standard stainless steel 3 x 3 subassembly. The enclosure can and grids wi.11 be of stainless l

steel but the fuel rods will be Zircaloy clad. The outer i

diameter of the fuel rods will be the same as that for the rods in the remainder of the core but the lower strength of the Zircaloy requires thicker cladding. The following dimensions will be observed on the Zircaloy rods:

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Outer ditneter of cladding inches Inner dianet(r of cladding inches Outer diameter of UO inches 2 Pellet In order to compenaate for the smaller diameter of the pellets, the enrichment of the fuel in tue Zircaloy rods will be increased to 6.1 wt %. This small increase in enrichment will allow the power generation per unit 'i cngth to be kept at the same level as that of the stainless steel rods. The enrichment will be' uniform throughout the subassenbly.

The Zircaloy subasser.bly will not contsin thermocouples for measure-ment of clad surface temperatures (or fuel temperatures) or a flux wire thimble. It will,however, have a pitot tube and coolant temperature thermocouple located at its outlet. Thin stainless steel encased cobalt-aluminum alloy wires will be located in the corners of the can for pos*,-irradiation measarement of integrated flux.

It is planned that the location of the Zircaloy subassembly be flexible, Ihpending on subsequent experiments, the assembly may be inserted in any one of the posoible subassembly locatf.ons with the exception of thi central location. The power generation per unit length of Zircaloy rod will b1 the same as that of the stain-less steel rods surrounding the subassembly.

6. In the test where boric acid injection is used to aid An reactor shutdown after a turbine trip, described in(d)on page 23,
  • approximately 12% boric acid solution will be injected by means-of one or both of the charging pumps. To compensate for most of the change in reactivity with power, it is expected that rufficient boron will be added to reduce the reactivity by about 1%.

If one charging pump is used for the boric acid injection, this will require approximately 50 seconds; :Lf both charging pumps are used, about 25 seconds are required. This compares with the approximately 20 seconds for the coolant to complete one cycle through the primary loop.

SAXTON NUCLEAR EX'PERIMENTAL CORPORATION (S E A L) y /s/ R. E. Neidic President

> Attest

/s/

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E. L. Barth Secretary Sworn and subscribed to before me this 10th day of April, 1962.

(S E A L) /s/ Martin A. Kohr Notary Public Muhlenberg Township, Berks County

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