ML20210S885
| ML20210S885 | |
| Person / Time | |
|---|---|
| Site: | Satsop |
| Issue date: | 02/19/1976 |
| From: | NRC |
| To: | Deyoung R Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-1650 NUDOCS 8605290482 | |
| Download: ML20210S885 (7) | |
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i FEB 19 IW6 Docket Nos. STN 50-5 509 Richard C. DeYoung, Jr., Assistant Director f or LWR's, DPM REVISION 2 TO SER - WASHING 1t)N PUBLIC POWER S PLY SYSTEM, UNITS 3 & 5 Plant Name: WPPSS 3 & 5 Licensing Stage:
CP Docket Nos.:
Milestone No. :STN 50-508/509 24-21 Responsible Branch & Project Leader:
Requested Completion Date:
LWR f3, A. Bournia Technical Review Branch Involved: Waiting on WPPSS Submittals Description of Review:
Reactor Systems Review Status:
to Update SER Complete thou WPPSS Amendment 28 ment 23 was reported in our letter to RThe Reactor Sys
& 5 thru Amend-Victor Stello, Jr., dated October 1
. C. DeYoung, Jr., from our review through WPPSS Amendment 28 We have now completed
, 1975.
CRSSAR Amendments 38 thru 41 and which al, which includes response to design revisions accomplished since our pre i6so incorporates major BOP we have discussed Amendment 29 with the appli v
us review.
In addition, the cosunitments which follow:
cant and have obtained (1)
The WPPSS 3 & 5 CP application will take no Amendment 28 and prededing submittalsCESSAR oth exceptions to n
ied in (2)
Section 6.3.2.14 will be amended to include ting in the recirculation mode. evaluation of available NPSH a design opera-(3)
Intake screens on the containment sump and maximum particle size entering the ECCS pipin at the exit to m t the with CESSAR interfaces R-2 and R-3 on page 1 8 43 n accordance WPPSS PSAR.
This design change is to be confirmed in of the Amendment 29.
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SAFETY EVALUATION OF OUTSTANDING ISSUES The status of the Reactor Systems Branch evaluation of outstanding issues as enumerated in our letter to R. C. DeYoung, Jr., dated October 1, 1975 Revision 1 to SER, is described below:
CESSAR Unresolved Items (1) In response to the staff " Technical Report on AnticipattJ Transients Without Scram for Light Water Reactors," WASH-1270, CESSAR references two CE topical reports. One report, CENPD-158, presents the ATWS transient analyses specified in WASH-1270 and the other, CENPD-148, describes the common mode failure review of the reactor shutdown system also required by WASH-1270. In Amendment.42 to CESSAR it is stated that, "When the ATWS calculational models and analysis methods are approved, the safety valve capacity needed to meet the Class B ATWS pressure criterion will be established for the Sys cm 80 design."
The staff has completed the review of these CE topical reports and issued a " Status Report on Anticipated Transients Without.
Scram for Combustion Engineering Reactors," on December 9, 1975, which reports the results of this review. This report concludes that these analyses do not assure that postulated ATWS events with calculated consequences greater than the limits specified'in WASH-1270 are likely to occur less frequently than the safety goal stated in WASH-1270. The status report describes assumptions regarding analysis methods, reactor system parameters, and the operability and performance of other plant systems which, if incorporated in the analyses, would provide the required assurance, Therefore, we will require WPPSS to provide revised analyses of this plant in accordance with the requirements stated in the status report or in some other acceptable manner prior to issuance,
of a CP.
In addition, the conceptual design of the changes indicated by the analyses and others specified in the status report should be described. This description should provide the performance of systems, for example, the number and capacity of additional safety valves, and the reliability criteria including the independence and diversity requirements to be applied to both fluid and instrumentation systems for which credit has been taken in the analysis.
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% (2) Design Changes to the Shutdown Cooling System to Satisfy GDC 34 - CESSAR interface R-9 on page 1.8-59 of the
'WPPSS PSAR defines power supply requirements for the Shut-down Cooling System Isolation Valves. This interface has been accepted by the staff as in compliance with GDC 34 including an assumed single electrical failure. However,
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WPPSS is still evaluating the method for implementing the design change. This item will remain open until the specific method for satisfying the single failure require-ments of this interface has been documented and found acceptable by EICSB.
(3) Previously resolved.
(4) ECCS Performance Evaluation - The staff has completed review of the ECCS performance evaluation submitted for WPPSS Units 3 and 5 and has concluded that the submittal and results therein are acceptable. Details of our review are provided in the letter from D. F. Ross to Richard C.
DeYoung, Jr., "ECCS Performance Evaluation for WPPSS Units 3 and 5", dated January 28, 1976.
(5) Previously resolved.
(6) Boron Dilution Analysis - The staff has concluded its review of the boron dilution incident described in CESSAR and has found the results of the evaluation to be accept-able. This item is therefore resolved for WPPSS 3 & 5.
(7) Repressurization of Safety Injection Tanks - The safety injection tank isolation valves will be interlocked with the pressurizer pressure measurement channels to open automatically as reactor coolant pressure is increased to 500 psig during startup. The staff has completed review of the procedures and design features governing the operation of these valves and the results of our review are summarized in Section 6.3.2 of the CESSAR Safety Evaluation Report, NUREG-75/112. We will require appropriate technical specifications to enforce the operation of these valves in accordance with the procedures proposed in CESSAR. This item is therefore resolved with respect to the WPPSS construction application.
WPPSS Unresolved Items (1) Previously resolved.
(2) NPSH Requirements for LPSI Pumps - The staff has reviewed the design evaluation of available NPSH for the LPSI pumps and the proposed procedures for flow throttling to assure l
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adequate NPSH for operation when taking suction from the sump. WPPSS 3 & 5 accident analyses do not take credit for operation of these pumps during post-LOCA coo'.ing of the containment sump water. We have concluded that the design and proposed use of these pumps is acceptable and consider this matter resolved.
(3) Conformance to Regulatory Guide 1.79 - The applicant, in Section 6.3.4 of Amendment 28 to the WPPSS 3 & 5 PSAR, has committed to preoperational testing, in accordance with Regulatory Guide 1.79, of those pumps required to operate during post-accident recirculation from the sump unless'it can be shown that similar tests by others are applicable to the WNP-3/5 design. We find this commitment acceptable and consider this matter resolved with respect to the construction authorization.
(4) Steam Line Break Analysis - In response to CESSAR interface I-21 on page 1.8-18 of the WPPSS 3 & 5 PSAR, the applicant has committed.to restrict the steam blowdown in all.normally open paths downstream of the Main Steam Isolation Valves, following a MSIV closure signal, to the maximum acceptable value to be specified in the CESSAR FSAR. We find this commitment acceptable and consider this matter resolved with respect to the construction authorization.
(5) Compliance to CESSAR Interface Requirements (general) -
Reactor Systems Branch has reviewed the WPPSS response to those CESSAR interface requirements which are pertinent to the safety evaluation for the systems and accident analyses included in the RSB scope of review. Included are those BOP provisions associated with our acceptance of the following:
a.
overpressure protection of primary and secondary systems, b.
integrity of the reactor coolant pressure boundary, c.
cold shutdown capability under normal and accident conditions assuming the most limiting single failure in required systems, d.
auxiliary feedwater and main steam and feedwater system characteristics inherent to the accident analyses, e.
emergency core cooling capability assuming the most limiting single failure in required systems, f.
reactivity control including boron injection capability.
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g The applicant has taken exception to several of the CESSAR interfaces and has proposed alternate design methods to satisfy the safety requirements. In addition to the specific problems addressed by other items of this report, the appli-cant has agreed to the following actions in response to staff concerns about interface provisic.ns.:
(a) Minimum Capacity of Atmospheric Steam Dump Valves - The applicant has proposed to install atmospheric steam dump valves of significartly smaller capacity (140,000 lb/hr of 300 F saturated steam) than that assumed in the CESSAR safety evaluation which was approved by the staff. In response to staff requests, detailed analyses have been performed to evaluate the effect of these smaller vaivus on:
(1) the tiae required to accomplish a cold shutdown under normal and accident conditions when the il nain condenser is not available, (2) auxiliary feedwater requirements to compensate for decay heat during the longer ecoldown time, and (3) the effect, if any, on results of accident analyses previously reviewed.
Le have reviewed the results of the cited analyses and conclude that the modified BOP design proposed by the applicant is capable of bringing the reactor to I
a cold shutdown condition within a reasonable period of time following shutdowns, assuming the most limiting single failure. We find the modified design acceptable for a construction permit.
(b) Maximum Particle Size of Impurities in Safety Injec-tion Coolant - In responte to staff concerns the applicant has agreed to conform to CESSAR interface re-quirements for filtering of water supplies to the safety injection system. CESSAR requires that screens in the containment sump and at the exit of the refueling water tank, prevent passage of particles exceeding 0.1 inches in diameter. The applicant had proposed limiting the particle size to 0.25 inchas in diameter and is still reviewing this requirement with Combustion Engineering.
The staff will require that screen sizes remain in accordance with CESSAR interfaces. Any revisions must be justified on the CES3<a docket.
(c) Minimum Storage Capacity of Auxiliary Fcedwater Supply -
Based on the reanalysis of auxiliary feedwater requirements for reduced size atmosi heric steam dump valves, the L
o s-applicant has determined that 320000 gallons of feedwater will be needed for recovery from the main steam line break accident. The plant design will previde for 320C00 gallons of condensate storage instead of 25000G gallons previously committed. We find this design revistun acceptable and consider this matter resolved.
(6) Shutdown Cooling Requirements - The CESSAR Shutdown Cooling Heat Exchangers are rated for' a tube side (primary coclant) flow of 5000 gpm and a shell side (component cooling water) flow of 11000 gpm at maximum inlet temperature of 1200F. The applicant proposes to operate these units with the same tube side flow but with shell side flow of 3500 pgm with 950F inlet temperature for normal shutdown with both trains in service.
For emergency shutdowns or post-LOCA cooling of sump Water, the applicant proposes.to increase the shell side flow to 6000 gpm by removing non-essential services. The component cooling water supply temperature would be maintained at 1200F using one cooling tower for each train as the heat sink.
Due to the departure from CESSAR interface requiremen:s (11000 gpm minimum shutdown cooling flow with maximum inlet temperature of 120 F), we have required a detailed submittal with comparison to CESSAR of the 30CHX operating conditions for the cooldown transient. The staff has reviewed the data and concludas that a single train of the shutdown cooling system (assuming a failute which disables the other train), operating with the cooling water conditions proposed by the applicant, $r capable of accomplishing an emergency plant cooldown in a reasenable period of time, and is also capable of accomplishing the long term recirculation ecoling required consistent with the containment transient analysis provided by the applicant.
The dry cooling towers most each be capabic of a duty of 150 x 106 Btu /hr heat load from the SDCHX in addition to the other essential heat loads to maintain the required component cooling water inlet temperature of 120 F.
We find the proposed SDCHX coaling water supply provisions acceptable for a construction permit.
(7) Post-LOCA Cooling Requirements - We consider this item resolved based on the review described in the preceding item.
(8) Removal of Fower from Atmospheric Dump Valves - The appli-cant now proposes to meet the CESSAR interface by designing control circuits for these valves to preclude spurious motion due to a single electrical failure.
We consider this item resolved.
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um me s (9) Removal of Power from Main Steam Isolation Valve Bypass Valves - These valves are used only for brief periods during plant start-up to heat up the main steam lines and to equalize pressure across the Main Steam Isolation Valves prior to opening. The applicant has proposed to remove power from the valve actuators during power operation in lieu of designing the control circuits to preclude valve maloperation upon the occurrence of single failures.as required by the CESSAR interfaces. For these valves, the staff concludes that removal of power from the valve control circuits is an acceptable means for protecting against single electrical failures. Technical specifica-tion will enforce the administrative procedures governing the restoration and removal of power from the valves.
(10) Protection of Safety Injection Tanks from Pipe Whip - The applicant has indicated in discussions with the staf f -that the steam line break is the only potential pipe rupture which may result in consequential damage to the safety injection tanks. Since the safety injection tanks are not needed for recovery from a steam line break accident, the applicant's position is acceptable. The PSAR interface responses have been subsequently modified such that further clarification of the record is not needed. We consider this issue resolved.
Additional WppSS Item (1) Loose Parts Monitoring - A CESSAR interface requires in-stallation of a loose parts monitoring system having the capability to detect an impact of one-half foot pound or more on internal surfaces of the Reactor Coolant System.
The applicant is committed to install such a system but is still evaluating the extent of compliance with sensiti-vity requirements, If the loose parts monitoring system to be provided by the applicant does not meet all inter-face requirements, we will require that a detailed descrip-tion be submitted for approval of the staff prior to installation of the system.