ML20211L470

Suppl 1 to 851104 Rev 1 to Application for Amend 114 to License DPR-54,revising Tech Spec 3.5.1.8 & Adding Prestartup Surveillance Test Requirement to Items 13a & B of Table 4.1-1

ML20211L470
Person / Time
Site:	Rancho Seco
Issue date:	12/09/1986
From:	Julie Ward SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Miraglia F Office of Nuclear Reactor Regulation
Shared Package
ML20211L474	List: ML20211L470 ML20211L479
References
GL-83-28, GL-85-10, JEW-86-880, NUDOCS 8612160039
Download: ML20211L470 (5)

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S ACRAMENTo MUNICIPAL UTILITY DISTRICT 16201 s Street. P.o. Box 15830. Sacramento CA 95852-1830.1916)452-3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA JEW 86-880 December 9, 1986 DIRECTOR OF NUCLEAR REACTOR REGULATION ATTENTION FRANK J MIRAGLIA JR DIRECTOR PWR-B DIVISION U S NUCLEAR REGULATORY COMMISSION WASHINGTON DC 20555 DOCKET NO. 50-312 LICENSE NO. DPR-54 PROPOSED AMENDMENT NO. 114, REVISION 1, SUPPLEMENT 1 On October 19, 1984 and November 4, 1985, the Sacramento Municipal Utility District submitted Proposed Amendment No. 114 and its Revision 1, respectively.

These submittals were in response to Generic Letters 83-28 (Items 4.3 and 4.4),

and 85-10. Subsequent to the District's submittal of Proposed Amendment No.

114, Revision 1, the NRC recommended an additional sentence to be included in LC0 Specification 3.5.1.8 regarding actions to be taken on conditions of inop-erable SCR relays. This supplement to Proposed Amendment No.'114, Revision 1 adds the NRC recommended sentence to Specification 3.5.1.8, and also adds a pre-startup surveillance test requirement to Items 13a and b of Table 4.1-1 which, through oversight, had not been included in Proposed Amendment No. 114, Revision 1.

Attachments I, II and III provide the Safety Analysis, "No Significant Hazards" Evaluation and Description of Proposed Changes, respectively.

Pursuant to 10 CFR 50.91(b)(1), the Radiological Health Branch of the Califor-nia State Department of Health Service has been informed of this Supplement by copy of this submittal.

The District has determined that no license fees are required since a check for

$150.00 was sent to the Commission with the initial submittal of Proposed Amendment No. 114.

Should you require any further information with respect to this Proposed Amendment supplement, please contact Mr. Ron W. Colombo at Rancho Seco Nuclea enerating Station Unit No. 1.

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Subscribed and sworn to before me, DEPUTY GENERAL MANGER this 9" day of 3ecemgr,1986 NUCLEAR l /

cc: REGION V (2) O MO f MIPC (?) Notary Public T O INP0 g OiFICIAL SEAL 8612160039 e61209 2 s DMVN DMWG PDR ADOCK 0500 .! , N07ARYPucoc cAurcas:A P SACRACTo COUNTY an

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. ATTACIMENT I SAFETY ANALYSIS INTRODUCTION This supplement to Proposed Amendment No. 114, Revision 1, adds the following sentence (shown underscored) to Specification 3.5.1.8 as originally submitted in Revision 1:

The SCR relays for the regulating rods duplicate the trip function of the DC breakers for the safety rods. With the number of oper-able SCR relays one less than the total number of relays in a channel, restore the inoperable SCR relay to operable status in 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or place the SCRs associated with the inoperable relay in trip in the next hour. With two or more SCR relays inoperable, place all SCR relays associated with that channel in trip in the next hour.

In addition, the surveillance requirements for CRD Trip Breaker RPS Undervol-tage Trip and RPS Shunt Trip, Items 13a and 13b in Table 4.1-1, are augumented from their existing monthly frequency (M) to include the requirement for test-ing prior to each startup (P), if not done the previous week.

The above indented paragraph, less the underscored sentence, was submitted October 9, 1985 by the BWOG in response to Generic Letter 85-10, and was transmitted to the NRC by the District on November 8, 1985 as Proposed Amendment No. 114, Revision 1. Subsequently, the NRC gave approval on l December 6, 1985 to the BWOG wording, contingent on the addition of the sentence shown underscored above. Accordingly, the underscored sentence is being added to the previous submittal of Proposed Amendment No. 114, Revision 1.

The added surveillance requirements for Items 13a and 13b in Table 4.1-1 were stipulated in Generic Letter 85-10, but through oversight were not in-cluded in the submittal of Proposed Amendment No. 114, Revision 1.

EVALUATION AND BASIS FOR SAFETY FINDINGS Systems / Components, Safety Functions Affected The affected systems / components and associated safety functions are described by the following excerpts from USAR Section 7.2.2:

The control rod drive system consists of three basic components:

(1) control rod drive motor power supplies, (2) system logic, and (3) trip breakers. The power supplies consist of four group power supplies, an auxiliary power supply, and two holding power supplies. The group power supplies are of a redundant six-phase, half-wave rectifier design. In each half of a group power supply, rectification and switching of power is accomplished through the use of silicon controlled rectifiers (SCRs).

This switching sequentially energizes first two, then three, then two of the six Control Rod Assemblies (CRA) motor stator windings in stepping motor fashion to produce a rotating magnetic field for the control rod assembly motor to position the CRA. Switching is achieved by gating the six SCRs on for the period each winding must be energized. As each of the six windings utilize SCRs to supply power, six gating signals are required.

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ATTACl#ENT I con't Rod drive control system trip breakers and contacts are provided to interrupt power to the control rod drive motors. When power is removed, the roller nuts disengage from the lead screw and a gravity free-fall trip of the CRA occurs. Two series trip methods are provided for removal of power to the CRA motors. First, a trip is initiated when reactor protection system logic interrupts power to the undervoltage (UV) coil of the main a-c feeder breakers.

Second, a trip is initiated when the silicon control rectifier gating power and the d-c holding power is interrupted. As parallel power feeds are provided on both holding and gating power, interruption of both feeds is required for trip action in either method of trip.

A reactor trip occurs whenever power has been removed from the rod drive motors. The design provides two stored energy breakers (RPS Undervoltage Trip), which do not require power to interrupt the electrical feeds to control rod drive power supplies, and a second set of circuit-interrupting devices (RPS Shunt Trip), which are in series on the output of the power supplies. All devices have suff-icient interrupting capacity to open under any group load config-uration. Reactor trip is further assured by provided series trip devices, split buses, and provisions for periodic testing.

This proposed Technical Specification supplement does not require a change to the USAR, and is soley an addition to Technical Specifications. Its approval is not required prior to restart.

Effects on Safety Functions and Analysis of Effects The original concern expressed by BWOG (10/09/85 submittal) was that a one hour LC0 associated with a single inoperable SCR relay was overly conserva-tive and would "significantly increase the likelihood of inadvertant rod drops resulting in unneeded challenges to other plant safety systems." Thus, a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> LC0 was proposed and approved associated with a single inoperable SCR relay. The case of multiple (more than one) SCR relays being inoperable raises certain common mode failure / reliability concerns, and the proposed LC0 supplement is appropritely conservative in addressing these concerns.

Similarly, the added surveillance requirements are appropriately conservative for assuring operability preceeding each startup.

No new failure modes are introduced. No adverse safety impact has been iden-tified. An unreviewed safety question is not involved.

Summary This supplement to Proposed Amendment No. 114, Revision 1 adds an NRC recom-mended sentence to the previously submitted Action statement for inoperable SCR relays. Also added are the surveillance requirement for RPS Undervoltage and Shunt Trip relays after each refueling outage. Both of the above changes are in compliance with Generic Letter 85-10 and conform to the NRC's revisions to the Model Standard Technical Specifications. This supplement maintains an appropriate level of conservatism is assuring the reactor trip function.

This supplement is not a change to the facility as described in the USAR. An unreviewed safety question is not involved, and the health and safety of the public is maintained.

o ATTAC K NT II "N0 SIGNIFICANT HAZARDS" EVALUATION Supplement 1 of Proposed Amendment No. 114, Revision 1 adds a further sentence to the action requirements in Specification 3.5.1.8 as earlier submitted in response to Generic Letter 85-10. This added sentence was recommended by the NRC as a condition of acceptance of the earlier action wording as submitted initially by the BWOG and subsequently as part of Proposed Amendment No. 114, Revision 1.

In addition, the surveillance requirements for CRD Trip Breaker RPS Undervoltage Trip and RPS Shunt Trip, Items 13a and 13b in Table 4.1-1, are augmented from their existing monthly frequency (M) to include the requirement for testing prior to each startup (P), if not done the previous week.

The District has reviewed the above changes proposed by this supplement te Proposed Amendment No.114, Revision 1 against each of the criterion of 10 CFR 50.92 and concluded that plant operation with the above administrative changes to the Technical Specifications would not:

a. involve a significant increase in the probability or con-sequences of an accident previously evaluated, or create the possibility of a new or different kind of accident from any previously analyzed.

The proposed changes are purely administrative, having no adverse effect on plant safety or operation. For this reason, the changes are judged as having no accident potential,

b. involve a significant reduction in a margin of safety.

As stated above, the proposed administrative changes have no adverse effect on plant design or operation. There-fore, margins of safety are also judged as unaffected.

On the basis of the above, the District ccncludes that the proposed changes, purely administrative, do not constitute any significant hazard, and in no way endangers the health and safety of the public.

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. ATTACHMENT III DESCRIPTION OF PROPOSED' CHANGES .

1. Specification 3.5.1.8, page 3-25a: Added the following sentence: "With two or more SCR relays inoperable, place all SCR relays associated with that channel in trip in the next hour."

2. Table 4.1-1, INSTRUMENT SURVEILLANCE REQUIREMENTS, page 4-4: Added the test frequency designation: "P" meaning: " Prior to each startup if not done previous week" to Items 13a and 13b.

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