ML20085H468

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Amend 1 to Change Rept 16 to License DPR-4,describing Mods to Safety Injection Sys & Installation of Automatic Long Term Coolant Recirculation Sys
ML20085H468
Person / Time
Site: Saxton File:GPU Nuclear icon.png
Issue date: 07/08/1969
From: Neidig R
SAXTON NUCLEAR EXPERIMENTAL CORP.
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ML20083L048 List: ... further results
References
FOIA-91-17 NUDOCS 9110280282
Download: ML20085H468 (7)
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SAXTO:: !;UCLEl.R EXPr.h1 MENTAL CORPOR/.710;i 4 ,

DOCKET l'O. 50-146 LICD;6E DPR-4 Aniendmeri. Nt. 1 to Change Report No. 16

1. On 1:ovember 13, 1968, Applicant subtaitted Change Report No. 16 describing modificatinus r:at'e to the safety injection system and the installation of an automatic, long-term et ' ant recirculation .

systen. The section, " Safety Considerations", has been revised and this revision d e being rubtitted as Amendttent No. I to Change Report No. 16.

SAXTON NUCLEAR EXPERIMENTAL CORPORATION ny /c/ P. E. Meidic,

, R. E. Neidig, President b

July 8, 1969 9110280282 910424 PDR FOIA PDR DEKOK91-l"'

  • Docket 1;o. 50-146 1)PR-4 Chance Report. No.16 4 i 4

Amendnent No. 1 ClitdiGE lEPORT FOR INSTALLATIOI: OF LONG-7DN RECIRCULATION SYSTD1 AND INJECTION SYSTDI CIRCUITRY t

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- Change Poport No. 16 Yage 2 of 6 Parps d

NW3A UO' 3 Safety _ Injection Syr. ten hach of the tuo cafety injection lines feeding the reactor vessel is cupplicd with a flow indication channel taounted on the main control board. The logie in the esisting circuit for detecting a rupture of one of the safety injection lines and closing the associated isolation valve is based on a two to one flow ratio in the two injection lines. If the flow ratio exceeds two to one, the isolatiot.

valve in the line with the higher flow is autoraatically closed. To preclude isolation of an intact line, in the event the isolation valve in the remaining line should fall to open, the circuit vill be modified te require indication of an open flow path in line uith the lower flow prior to closing of the isolation valve in the line uith higher flow. The modification will include a position.

signal indicating the valve is in an open position to ensure that the flow path is open as choun in rigure 4.

The safety injection actuation circuitry has been analyzed from the standpoint of an active component failure preventing automatic operation. Failure of the master actuation relay, operating coil, or its fuse could prevent automatic safety injection. Uith col] or fuse failure the operator vould trip the-relay manually.

Mechanicel failure of the relay would require the operator-to manually start the pumps and operate the valves. To increase the reliability for automatic initiation, the circuit vill be modified-by addition of separate relay, operating coi1~, and fuse in parallel as shown in Figures 5 and 6.

1 Purpose of Change The purpose of thic change is'to enhance the cafety characteristics of the Saxton Reactor (as described-ir. the previously submitted Saxton - Loss of Coolant Accident Prevention and PMeet Ion Report)- by providing long-term cooling for decay heat removal, increasing the reliability of the Safety Injection System and adding - ,

redundancy to the actuation circuitry.

Safety Considerations The design, fabrication and erection of the-recirculation system pgping was made in accordance with USAS B31. 1967 Edition.

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A t.chemat te of the syst un is che.cn in rigure 1. The recirculation reservoir is a stainlets stec3 tanh provided to incure a source of cican water for periodic testing of the syriten. The recirculation pumps are designed and installed to operate, immerscJ in 'borat ed water. The motor operated isolation valves ace located in the piping to that they will not be immersed. The valves arc, however, designed to operate in a 40 psig, 280 F, saturated steam environment. The system piping f ron the reservoir to the check valves (VR7 and VR8) downstreara of the pumps is designed for ISO psig and 280 F. That part of the system from the chech valves to the cor.nection to the safety injection piping is designed for 2500 psia and 650"F. Two new check valves (3V251A and 3V253A), designed for 2500 pria and 650 r, have been installed in the safety injection piping as a part of the recirculatJon system.

The integrity of the recirculation and safety injection system was assured by conforniq t o the f olloving Code requirements:

1. Ueldern and veld procedures were qualifi2d in accordance with ASME Beiler and Prcncure Vecsc1 Code,Section IX.
2. Root and ijna.1 pans of all welds were liquid peactrant inspected and all but't veldc were 100% radiographically'inopoeted. The procedures and acceptance standards'were in accordance with ASME Boiler and pressure Vessel Code,Section I. .

Peragraph 137.1 of B31.1 requires that all piping systems designed, fabricated and erec_tcd under the Code demonstrate Icak tightness, which must be met by a hydrostatic test prior to initial operation. Where a hydrostatic test is not practicable an initial service leak test, a vacuum test or 100% radiography of all wclded joints in an all welded system may be substituted. Paragraph 137.4.1(b) further specifies that the hydrostatic test, if performed, chall be conduct.ed at-a test pressure of 1.5 x design pressure unicss a lesser pressure is indicated by Parag'raph 137.4.1(a). Paragraph 137.4.1(a) specifics that the test pressure shall not exceed the maximum test pressure of any vessel or-components in the piping system. Reference to Figure 1 shows that in order to hydrostatically tent the new piping, tbc reactor coolant system will be subjected to the s'aue hydrostatic pressure. Therefore, the practicability of conducting such a tect is lioited by the maximo pressure capability of the reactor coolant system.

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  • 'DFn-4 C',ange IRport 1:0, 16 Page 4 of 6 pages 4

h =rh:i no. 1 In determining the maximum pressure capability of the reactor coolant system the follouing conditions were considered:

1. Pressure retaining components in the reactor coolant system include austenitic stainless steel piping end fittings, and low alloy steel.
2. UDY shi f t and thernal stress considerations for the lou alloy steel in the reactor vescel 11rtit minitum systen temperature to 520 F for approximately system design pressure.

The allouable strees for austenitic stain 1 css steel in both the ASMg Boiler and pressure Yessel Code and USAS E31.1 recognizes the work-hardening characteristics of these materials by permitting the allowable stress at elevated temperature to reach 90% of the minimum 0.2% of fset yield strength at the specific design temperature. A footnote to Tables A-1 and A-2 of USAS B31.1 cautions that allouchle stress is 90% of yield strength, and for some loading conditions undesi re'>] e plastic def orv.ation could occur. Section 111 of the ASMg Loller and Preasure Vessel Code provides a more quantiti tive watning by lin.iting t.ny test precsurc to the 3csser of 1.25 x design pressure or that which produces a stress equal to 90% of the waterial yield strength at the test temperature. Therefore, the limiting pressure for the reactor coolant system at a temperature of 5200r is set by the aurenitic stainless steel piping and fittings in the system.

The reactor coolant system piping (centrifugally cast) and the reactor coolant system fittings (static cast) were designed, fabricated and erected in accordance A

vith USAS D31.1 - 1955 Edition, and nuclear piping Cases N-9 and N-10 respectively. The material property data curves are the same for both components; therefore, the allowabic stresses as set forth in Cases N-9 and N-10 are identical.

The maximum allowable stresses for the system design temperature and the leak test temperature are:

For a design temperature of 650 r, Sa = 15,000 psi for a leah test temperature of 520 r, Sa = 15,720 psi

  • Casen N-9 and N-10 are attached 1

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, bPR Chante Report No. 16 Page 5 of 6 pages i

, Amend:wnt No.1 l

Thus, the r.av.Jnum Icah test pressure to which the reactor coolcnt system tuay be subjected to ctay within the 90% yield strength limit is:

3-f x 2485 a 2004 psig where: 2485 psig is reactos coolant system design pressure.

In viw of the quality control exercised during f abricatien and erection, and the une of radiographic and liquid penetrant exeminetions to verify the strv>:tural adequacy, the use of 2604 psig is an unnecessarily high prercurc to demonstrate leak tightner.s of the recirculation and safety injection systems.

Therefore, the syctems v113 be leak tested at a pressure of 2500 psia (system design presrure), while the reactor coolant system is maintained at a olight3y higher prennure of 2575 pnia.

  • Constroetien qun3Jty control for the electrical and instrum:ntation inctallations vill be assured by integrctir.: pernanently assigned Ucctinghouse technicians with the centractor personnc3. Further the overal"1 installation vill bc continuovely monitored by an 'NPS IEC engineer or the Westinghouse r.ite resident.

enginecr. .

The NationcI Fire Protection Association, National Electrical Code, Manufccturers-recommended insta11atica instructions, Westinghouse handbook for Inspection and Test of Electrical Equipment, Westinghouse Ulring Checklist, and Westinghouse Electrical Equipment Test Records vill all be used as a guide- to assure proper installation.

A comprehensive functional tect procedure has been defined for. nuclear power.

plant cystems by Westinghousc. This test procedure in to be conducted by Westinghouse and the Saxton Nuclear Experinental Corporation as~part of the acceptance testing.

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Opn-4 Change Repot t !!a, 16 Pace 6 of i Pages Amendinent 1 o.1 f

To deu:oantr.ite the avallabiJity of the 1:ociiculat. ion Syoten and to ensure satisfactory operation of system cociponents, pump relays and automatic actuation circuitry, the tecirculation System vill be tested monthly in conjunction vith the routine test of the Safety Injection System. ..

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