AECM-86-0159, Application for Amend to License NPF-29,changing Tech Specs to Resolve NRC Concerns Re Core Stability & to Support Single Loop Operations

Application for Amend to License NPF-29,changing Tech Specs to Resolve NRC Concerns Re Core Stability & to Support Single Loop Operations

ML20206J517
Person / Time
Site:	Grand Gulf
Issue date:	06/20/1986
From:	Kingsley O MISSISSIPPI POWER & LIGHT CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20206J522	List: AECM-86-0159, Application for Amend to License NPF-29,changing Tech Specs to Resolve NRC Concerns Re Core Stability & to Support Single Loop Operations ML20206J534
References
AECM-86-0159, AECM-86-159, TAC-61083, TAC-61357, NUDOCS 8606270186
Download: ML20206J517 (10)

Text

'

MISSISSIPPI POWER & LIGHT COMPANY M

] Helping Build Mississippi P. O. B O X 16 4 L J ACKSON, MISSISSIPPI 39215-1640 O. D. KINGSLEY, JR.

vica rassion=t muctamaoannarious June 20, 1986 U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 Attention: Mr. Harold R. Denton, Director

SUBJECT:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 File: 0260/0840/L-860.0 Proposed Amendment to the Operating License (PCOL-86/05) -

Additional Information (CS/ SLO)

AECM-86/0159

REFERENCES:

1. AECM-86/0092(March 31,1936)

2. AECM-86/0129 (May 2, 1986)

3. AECM-86/0160 (June 2, 1986)

In accordance with the provisions of 10 CFR 50.59 and 50.90, Mississippi Power & Light Company (MP&L) requested an amendment to License NPF-29, for Grand Gulf Nuclear Station (GGNS) Unit 1 in its letter dated March 31, '986 (Reference 1). The requested amendment pertained to those changes to the plant's technical specifications necessary to resolve NRC concerns regarding core stability and to support single loop operations (CS/ SLO).

The requested amendment has been the subject of a series of conversations between the NRC (Mr. L. Kintner and Mr. G. Thomas) and MP&L. The NRC Staff has identified three areas where additional information is required and a fourth area where a revised technical specification change should be proposed.

Attachment 1 provides the documentation to support resolution of the subject NRC concerns.

As noted in References I and 2, it is requested that the changes for core stability and single loop operation be implemented concurrently with those proposed for the Maximum Extended Operating Domain (ME00). The ME00 related changes were proposed in PCOL-86/07 and submitted May 2, 1986 (Reference 2).

8606270106 860620 PDR ADOCK 05000416 P PDR , 00 J14AECM86052101 - 1 Member Middle South utilities System

AECM-86/0159 Page 2 During discussions on these changes, MP&L noted that there are several technical specification pages which are common to both the CS/ SLO and the ME00 PCOLs. To support your staff's review, an integrated package of proposed MEOD and core stability / single loop operation technical specifications was prepared and submitted via Reference 3.

In the process of reviewing the additional changes contained in Attachment 1, MP&L discovered that the integrated package of proposed ME0D and CS/ SLO technical specifications was not complete. This was discussed with the NRC Project Manager, Mr. L. L. Kintner, on June 16, 1986. Attachment 2 contains the complete integrated ME0D and CS/ SLO technical specification changes, including those proposed in Attachment 1.

In accordance with the provisions of 10 CFR 50.30, three (3) signed originals and forty (40) copies of the requested information are enclosed. The attachment provides the complete technical justification and discussion to support the requested revisions to the original submittal. This amendment has been reviewed and accepted by the Plant Safety Review Committee (PSRC) and the SafetyReviewCommittee(SRC).

Based on the guidelines presented in 10 CFR 50.92, it is the opinion of MP&L that this proposed amendment involves no significant hazards considerations. As these changes provide additional clarifying information, and '

more stringent Technical Specifications requirements, it is MP&L's opinion ,

that additional public notice is not necessary.

Your uly, ODK:dm Attachments: 1. GGNS PCOL-86/35 - Additional Informat n

2. Revised Integrated Technical Specifications I

cc: Mr. T. H. Cloninger (w/a) l Mr. R. B. McGehee (w/a)

Mr. N. S. Reynolds (w/a)

Mr.H.L. Thomas (w/o) i Mr.R.C. Butcher (w/a)

]

Mr. James M. Taylor, Director (w/a)

Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission l Washington, D. C. 20555 '

Dr. J. Nelson Grace, Regional Administrator (w/a)

11. S. Nuclear Regulatory Comission Region II 101 Marietta St., N. W., Suite 2900 i Atlanta, Georgia 30323 l Dr.AltonB.Cobb(w/a)

State Health Officer State Board of Health l Box 1700 I Jackson, Mississippi 39205 J14AECM86052101 - 2

AECM-86/0159 '

Page 3 bec: Mr. L. F. Dale (w/a)  :

Mr. J. E. Cross (w/a)

Mr. T. E. Reaves (w/a)

Mr. S. M. Feith (w/a)

Mr. C. R. Hutchinson (w/a)

Mr. F. W. Titus (w/a)

Mr. L. l. Kintner (w/a) '

Mr. S. H. Hobbs (w/a)

Mr. J. G. Cesare (w/a)

Mr. L. L.

Mr. M. F. Crawford Daughtery(w(w/a)

/a)

Mr. Y. Balas (w/a)

Mr. F. G. Burford (w/a)

Mr. W. E. Clegg (w/3) '

MSS Nuclear Activities (w/a)

File (LCTS) (w/2)

File (Central) (w/a) ( )

t i

r

+

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J14AECM86052101 - 3

BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION LICENSE NO. NPF-29 DOCKET NO. 50-416 IN THE MATTER OF l MISSISSIPPI POWER & LIGHT COMPANY and MIDDLE SOUTH ENERGY, INC.

i and SOUTH MISSISSIPPI ELECTRIC POWER ASSOCIATION AFFIRMATION 1

I, O. D. Kingsley, Jr., being duly sworn, stated that I am Vice President, Nuclear Operations of Mississippi Power & Light Company; that on l behalf of Mississippi Power & Light Company, Middle South Energy, Inc., and South Mississippi Electric Power Association I am authorized by Mississippi Power & Light Company to sign and file with the Nuclear Regulatory Commission, this application for amendment of the Operating License of the Grand Gulf Nuclear Station; that I signed this application as Vice President, Nuclear Operations of Mississippi Power & Light Company; and that the statements made and the matters set forth therein are true and correct to th best of my knowledge, information and belief, r A STATE OF MISSISSIPPI COUNTY OF HINUS l

SUBSCRIBED AND SWORN T0 befor me, a N9 ry Public, in and for the  !

County and State above named, thisj7A ay of Y sw , 1986.

Afaw hwJ . Y 1

y Notary Public My commission expires:

ur c.mizin t@n u. 21.19# .

J14AECM86052101 - 4

Attcchment i NLS-86/05

SUBJECT:

Additional Information Pertaining to Single Loop Operation DISCUSSION: The original submittal of the proposed core stability and single loop operation technical specification changes was made in AECM-86/0092 dated March 31, 1986. The PCOL has been discussed with the NRC staff and three areas have been identified where supplementary information or changes are required. These areas are:

1. Additionai information regarding the justification of CHANGES proposed to Specification 3/4.4.1.2 (item 15 ofPCOLjustification),

2. Revision of proposed ACTION 3.4.1.1.f, and surveillance 4.4.1.1.6

3. Editorial correction of proposed Figure 3.4.1.1-1, and JUSTIFICATION: Revised pages for insertion into the March 31, 1986 submittal have been prepared to address and resolve the NRC comments.

1. The NRC has requested additional discussion justifying the MP&L position that idle loop jet pump operability cannot be reliably demonstrated. This additional information is provided on the attached revised page 16 and new page 16a for insertion in the original PCOL.

2. ACTION 3.4.1.1.f and Surveillance 4.4.1.1.6 have been revised to shorten the time allowed to change the appropriate setpoints and limits following the change from two to one (or one to two) recirculation loops in operation. Insert 3/4.4-1 and its respective justification in the PCOL (see pp.15,16) have been i revised and are attached here. The time period has been I shortened from 12 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> at the request of the NRC. l The 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> time period is consistent with NRC position which has been utilized on other similar applications by i other utilities, with due consideration of inherent design differences between GGNS and other BWRs.

The to theAPRM setpoints time required are the to make themost changes limiting)(with of the respect setpoints and limits to be changed when an operating configuration change is made. Adjusting the setpoints for the APRM Flow Biased Scram and Rod block is more than a simple setpoint change. The circuitry which allows adjusting and calibrating these setpoints is contained in the Flow Control Trip Reference Card in each APRM. Since the setpoints are not constant but J14 MISC 86052201 - 1

i change with recirculation flow, the circuit for the i setpoint is somewhat complex. It includes six

! potentiometers for slope, scram offset, alarm offset, j scram clamp, alarm clamp, and setdown. It is further i complicated by a six second time constant time delay and by the fact that the setpoint should be checked at various flow inputs. Due to the interaction of the many separate adjustments the vendor manual clearly states:

"No individual adjustments should be made without accoinplishing the complete adjustment procedure".

MP&L has reviewed the calibration process and determined that the eight hour time period, which provides an average of one hour per APRM channel, represents a minimum estimate of the time required to perform this ,

operation. This estimate is for actual time in the panel by a qualified technician and does not include time for documentation and mobilization of qualified personnel. The eight hours time allowed is considered to be practical for planned operational changes to single loop operation. This time period, however, may limit switching to single loop operation in response to operational transients.

3. The NRC noted that " Region I" was not clearly identified in the submittal Figure 3.4.1.1-1. This figure is submitted as part of this package with Region I l identified.

SIGNIFICANT HAZARDS CONSIDERATION

The technical specification changes proposed in this

, submittal are revisions to the core stability / single loop

operation changes proposed on March 31, 1986. Also included is an expanded justification of the changes to specification a 3/4.4.1.2 which does not involve new specification changes.

These changes confirm agreements which have been reached with NRC staff regarding the previous submittal. Two of the above items are editorial in that they provide additional clarifying information and do not affect the plant design, operation or margin of safety. These changes do not involve significant hazards considerations.

The remaining proposed change (item 2, above) revises the time permitted to change the affected setpoints and limits following a change in the operating configuration of the recirculation system.

J14 MISC 86052201 - 2 J

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1 The allowable time is proposed in this submittal to be shortened from twelve hours to eight hours. The eight hour period is consistent with the NRC position, considering i

design differences between GGNS and other BWRs. The 3

shortened time period has been evaluated and found to involve no significant hazards considerations as outlined below: ,

a 1 1. The change does not involve a significant increase in the probability or consequences of an accident. The i proposed change shortens the time period in which to re-establish conservative setpoints and limits. The time period is not explicitly modeled in the safety evaluations so this parameter does not affect the probability or consequences of an accident.

I 2. The change does not create the possibility of a new or

different accident. As noted in the March 31, 1986

submittal, single loop operation has been thoroughly evaluated with respect to accident and transient analyses. No new or different accidents are created by j

i single loop operation.

i 3. The change does not involve a significant reduction in the margin of safety. This change, in particular, '

increases the margin of safety in that the time during i which the limits and setpoints may be unconservative has been reduced.

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The new ACTION 3.4.1.1.f.is added to address the LC0 restriction regarding the limits and setpoints which are dependent on the recirculation system configuration. The action statement provides an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> time period in which to adjust the affected setpoints and limits following an operational configuration change. If the change is not complete in 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, the associated equipment is declared inoperable or the appropriate limits are declared 'not satisfied". This declaration prompts entry into an ACTION statement of the appropriate referenced specification. For a change to single loop operation, the affected values are conservatively reduced. For the change to two loop operation, the restrictions may be relaxed to provide more operating flexibility within the original safety evaluations.

The new action 3.4.1.1.e is added to address the LC0 restriction regarding operation in Region IV of Figure 3.4.1.1-1. In accordance with the GE recommendations of i SIL-380, operation in this region should not be permitted. The region should be exited by either a power decrease or flow increase.

Surveillance requirements 4.4.1.1.1 and 4.4.1.1.2 are revised to accommodate operation with one loop out of service. Two new surveillances 4.4.1.1.3 and 4.4.1.1.4 are added to provide for regular verification of compliance with the new single loop operation LCO.

The new surveillance 4.4.1.1.5 is required in conjunction with ACTION 3.4.1.1.d to prevent thermal shock of the vessel. Based on GGNS startup test data, it was determined that the bottom head was swept during natural circulation conditions at power levels as low as 36% of rated.

Similarly, test data demonstrate that the bottom head was swept by all single loop flow rates when the operating recirculation pump was on high speed operation. A 1 conservatively broad condition, then, has been defined as less than 36% power and the recirculation pump not on high speed operation. Beyond these limits coolant circulation <

in the vessel will provide the assurance that the '

differential temperatures are maintained within acceptable l 1imits. # l l

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. The new surveillance 4.4.1.1.6 is provided to ensure the setpoints and limits are revised within a reasonable time, following a configuration change in the number of recirculation loops in operation. The 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is consistent with the ACTION statement for changing the limits (i.e.,3.4.1.1.f). An operating change to single

. loop operation necessitates a reduction in the limits and setpoints. The surveillance ensures the changes are made to preserve the margin of safety provided by the APLHGR limits and to maintain the same APRM setpoints-to-power relationship. For an operating change to two loop operation, the surveillance addresses an operational concern: the limits and setpoints maybe increased to provide less restriction than was needed during single loop operation.

14. FIGURE 3.4.1.1-1 Thermal Power Limits A new figure is provided to conveniently show the GGNS 80%

~

rod line in order to clearly define the surveillance regions. This figure is also referenced in Specification 3/4.3.10.

15. 4.4.1.2.1 REACTOR COOLANT SYSTEM JET PUMPS 1

Jet pump operability is assumed in the LOCA analyses for both two loop and single loop operation. However, the criteria for demonstrating operability has been developed considering the drive flow provided by the recirculation pumps. During single loop operation at GGNS, startup 4

testing has demonstrated that flow through the inoperable loop jet pumps is dependent upon the drive flow in the operating loop. When the operating loop flow is high, flow through inoperable loop jet pumps is in the reverse direction. At lower operating loop flow rates, however, natural circulation becomes the dominant influence on the inoperable loop jet pumps and the flow through these jet pumps reverts back to the normal forward flow. Based on this change in direction of flow through the inactive loop jet pumps there is a range over which the flow is nearly zero; this is indicative of a differential pressure across

the pump of nearly zero. Because of this, the existing criteria for operability do not provide a reliable demonstration of the operability of the jet pumps in an inactive loop. A more detailed discussion of each of the criteria for operability is provided below

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1 J13ATTC86010901 - 16

a. Indicated recirculation loop flow (i.e., pump flow):

For SLO, the operating loop recirculation flow characteristics change slightly from two loop operation. However, since the idle loop recirculation flow is minimal, this correlation clearly does not apply to the idle loop.

b. Indicated total core flow:

A definite correlation exists between total core flow and recirculation loop flow (i.e., recirculation pump flow). This correlation, however, is significantly different for two loop operation compared to single loop operation because of the influence of natural circulation on flow through the idle loop jet pumps.

This correlation, then, provides a reliable indication of jet pump operability during two loop operation and also for the operating loop jet pumps during single loop operation because total core flow g, is predominantly influenced by operating loop (s) flow. For the idle loop, however, the loop flow is zero and, as in a) above, the correlation does not apply to the idle loop.

It is acknowledged that both the operating loop and the idle loop jet pump flows influence indicated total core flow during single loop operation. This operability criteria cannot reliably be used, however, to indirectly check the idle loop jet pumps based on the operating loop flow to indicated total core flow relationship. This is due to two factors:

1) the contribution of the idle loop flow to indicated total core flow is relatively small, and

2) this contribution varies with both power level and operating loop flow.

c. Indicated diffuser-to-lower plenum differential pressure:

GGNS has experienced difficulty in meeting this surveillance during two loop operation at low loop flow conditions. During single loop operation, this surveillance would be even more difficult to meet for the idle loop. There exists a broad range of operating loop flow rates for which the idle loop jet pump flow rates and differential pressures are very near zero. The acceptance criteria of this surve.illance would impose a band based on a percentage of a very small number. Such a band is unrealistic to meet and would not provide a reliable indication of the idle loop jet pump operability. Therefore, this surveillance criteria is to be applied for operating loop jet pump only, in order to avoid unnecessary failures. This surveillance will be performed on the operating loop, although it is ,

expected to be difficult to pass at low flow conditions.

J13ATTC86010901 - 16a