ML20085D205

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Suppl 1 to Change Request 6 to Application for Amend to License DPR-4,revising Max Calculated Cooldown Reat of Main Coolant Sys While Operating Pressure & Temp W/Clean Core & W/O Equilibrium Xenon & Samarium Is 16 F
ML20085D205
Person / Time
Site: Saxton File:GPU Nuclear icon.png
Issue date: 03/22/1963
From: Neidig R
SAXTON NUCLEAR EXPERIMENTAL CORP.
To:
Shared Package
ML20083L048 List: ... further results
References
FOIA-91-17 NUDOCS 9110150336
Download: ML20085D205 (3)
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f SAXTON NUCLEAR EXPERIMENTAL CORPORATION DOCKET NO. 50-146 SUPPLEMCIT #1 to C11ANGE REQUEST #6

1. Applicant hereby submits Supplement #1 to Change Request #6 that

! vas filed on February 7,1963, in compliance with paragraph 3 of License DPR-4.

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N  ;. y OJ SAXTON NUCLEAR EXPERIMENTAL CORPORATION p c~ 7 (3 \9#g /s/ R. E. Neidig M By 3 gh% $'

President g 4%8,gs$$#

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Attest:

(S E A L)

/s/R.E. Sypher Secretary Svorn and subscribed to before me this 22nd day of March 1963 (S E A L) /s/ Martin A. Kohr Notary Public Muhlenberg Township, Berks County My Commission Expires Feb. 4, 1966 9110150336 910424 PDR FOIA DEKOK91-17 PDR e .

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  • arch 19, 1963 l' Docket No. 50-146 DPE-4 Technical Specifications Supplement #1 to Change Request #6 The following additional information and revision is submitted in support of Change Request f6:

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1. The maximum calculated coal down rate of the main coolant system while N

at operating pressure at.d temperaturg vith a clean core and without I equilibrium Xenon and Samarium is 16 F/hr. This cool-down rate vould, of course, decrease with a decrease in the main coolant temperature below the operating temperature of 520 F and this cool-down rate would also decrease during core life as firsion product inventory is built up.

2. Approximately twelve hours n.ay be required to repack the tnree pistons of the triplex, reciprocating charging pumps. It is only necessary to repack one picton at a time and it is estimated that approxirantely four hours vill be required to repack one piston. These estimated times can be either longer or shorter, depending on the working conditions and the condition of the equipent at the time the work is carried out.

3 It may be necessary to use the safety injection system during this re-packing operation in the event that three conditions occur simultaneously.

It vould be necessary for both the standby or operable charging pump and the main coolant pump to fail during the period when the core is clean prior to the build-up of equilibrium Xenon and Samarium. This is a relatively short period during early core life. The estimated cool-down rate of 16 oF/hr. vill allow approximately four hours' time before the main coolant vould cool down to 450 F, wv ich is a condition equivalent to a shutdown margin in excess of 1% vith all the control rods fully inserted with zero boron. While the probability of these three events l occurring ut one time seems very small, in the event this series of events did occur simultaneously, it vill be possible to complete the repacking l of the pump piston being vork2d on in order to place thga pump back in service before the main ecolant temperature reaches 450 F.

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' 4. The safety injection system would be used cnly in the remote event that the main coolant temperature reached h50 F or in the event that the main l

coolant temperature was dropping rapidly under the conditions described above. In the event it vould become necessary to use the safety injection system, vater containing 1200 pp boron could be pumped into the core intermittently by dropping the main coolant pressure to between 1700 and i 1800 psi. The safety injection system pumps vould operate in series under i this condition and since the pumps vould'be operating near their combined

! shut-off pressure of 1850 psi, the capacity of the pumps vould be con-siderably reduced below their rated capacity oi 375 gm. The capacity of l

these pumps in series at 1700 psi is approximately 240 g g . The total quantity of borated water that could be pumped into the system would be-limited by the free volume in the prescurizer which would be approximately 500 to 600 gallons as compared to a total main coolant system capacity of

-approximately 2500 gallons. Assuming complete mixing of 500 gallons of l vater containing 1200 pm of boron with the 2500 gallons of main coolant water, at essentially zero boron concentration, the average boron con-centration vould be approximately 200 pp and the average temperature l

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.. ech 19, 1963

' Docket No. 50-146 DPR4 Technical Specifications Supplement #1 (page 2 of 2) to Change Requent #6 Under these conditions the reactor would vouldbeapproximately385}F.

be shut down by at least 2 % vith all control rods interted. Part ial mixing of the 1200 ppm borated water vonld result in either a higher boron concentration in the core or less dilution of temperature so that the shutdown margin vould be greater than Eff. This shutdown margin plus a slover cool-down rate at the lover main coolant temperatures vould provide en additional period of several hours to get one of the charging pumps back in service. Calculations show that with all centrol rods in-serted in the core and 200 pq in the coolant the reactcr vill be just critical at approximately 225 F.

While the use of the safety injection system to back up the charging pumps is expected to be a remote possibility as pointed out above, the use of this system under these co.ditions subjects the reactor vessel to stress conditions that are less severe than those for the loss of coolant accident that was analyzed for cyclic stresses and reported in Westinghouse Report WOAP-1620, " Supplementary Technical Infomation on the Saxton Reactor Vescel,"

5 Substitute the following paragraph for the paragraph under item 1, "Descrip-I tion of Change," in ChanSe Request No. 6:

Change item 12 on page 11 of the Saxton Technical Specifications as amended on October 9,1962 to read as follows:

i A charging system consisting of two motor-driven horitortal, triplex, reciprocating pumps, each having an adjustable capacity of 3 to 15 gpm at a total dynamic head of 2500 psig, is provided to charge degasified, demincralized make-up vater, concentrated borated vater, and water fram the purification system back into the main coolant system. These pumps vill be in operable condition during power operation of the reactor, except that one pump may be rendered i_noperable for the purpose of minor maintenance such as repacking the three piston packing C lands one at a time, so that the pump can be placed back in service within a period of four hours, if necessary. .One or both of these pumps will operate intemittently as required for the purification system, and for volume control of the main coolant system.

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