ML20137M400

Safety Evaluation Accepting Power Ascension Program Proposed Test Mods

ML20137M400
Person / Time
Site:	Hope Creek
Issue date:	01/22/1986
From:	NRC
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ML20137M397	List: ML20137M394 ML20137M400
References
NUDOCS 8601280258
Download: ML20137M400 (6)

Text

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- SAFETY EVALUATION HOPE CREEK GENERATING STATION POWER ASCENSION TEST PROGRAM ACCELERATION i This safety evaluation describes the staff's review of a number of Hope Creek Generating Station - Power Ascension Program (PAP) test modifications proposed by Public Service Electric and Gas Company (PSE&G). These proposed test modifications were submitted for staff review as part of a program to accelerate power ascension testing for Hope Creek. The Hope Creek accelerated power ascension testing program is also the lead plant for generic changes for acceleration of the traditional General Electric Boiling Water Reactor power ascension test program.

The proposed test modifications discussed in this safety evaluation were sub-mitted by letters dated August 21, September 20, 23, and 30, 1985, (R. Mittl, PSE&G to W. Butler, NRC). This safety evaluation discusses the following tests:

1. Automatic Load Following

2. Test No. 17 - Core Performance

3. Test No. 27 - Recirculation Flow Control System

4. Test No. 12 - RCIC System

5. Test No. 13 - HPCI System

6. Test No.14A - Selected Process Temperatures

~ 7. Test Condition 4 - Natural Circulation Operation

.. 8. Test _No. 20 - Pressure Regulator -

9. Test No. 21A - Feedwater System Response Testing Discussion of the above tests follows:

1. DELETION OF AUTOMATIC LOAD FOLLOWING (ALF) TESTING The applicant proposed deleting all testing of the ALF function from the power ascension test program. The ALF portion of the Recirculation Flow Control System is a non-safety related function which is not intended to be used at present. Because the Automatic function is not going to be used, it is unnecessary to test this function of the Recirculation Flow Control System. If at some future time the ALF function is to be used, it can be tested at that time. The Automatic mode of operation should be physically disconnected from the Master Flow Controller and wired so that the system is in manual control in both Master Flow Controller Positions to prevent inadvertent use of the Automatic function. A similar deletion has been granted at other plants (e.g., Grand Gulf).

Therefore, if the Automatic function of the Master Flow Controller is physically disabled, deletion of testing of the ALF function is acceptable.

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2. SUBSTITUT!0H OF SURVEILLANCE TEST FOR CORE PERFORitANCE STARTUP TEST (TEST NO. 17)

The applicant proposed substitution of the Core Performance Technical Specification Surveillance test for the Core Performance Startup test to reduce duplication of testing.

The applicant maintains that adherence to plant technical specifications meets the objectives of startup test No.17 and the intent of Regulatory Guide 1.68 (Revision 2, August 1978), Appendix A, paragraph 5.b. The staff believes that the perfomance of the fuel themal margins technical specification surveillances simply allows operational personnel to determine that the plant is operating within its required limiting condition for operation and does not constitute a detemination "that steady-state core performance is in accordance with design" (Reg. Guide 1.68). The objective of Startup Test No.17 and Regulatory Guide 1.68 is that an engineering evaluation be perfomed to evaluate the actual themal and nydraulic parameters against design expectations for these l parameters and that it, in turn, receives the appropriate level of manage-ment attention. Accordingly, the applicant's proposed substitution of the Core Performance Technical Specification surveillance test for the Core Perfomance Startup test is not acceptable.

An alternative to the applicant's proposed substitution exists. It is the r

intent of Regulatory Guide 1.68, Revision 2, to utilize plant pr,ooedures wherever possible, both to validate the procedures and provide training for plant personnel in their use. In Section C, Regulatory Position, Part 2, of. Regulatory Guide 1.68, it states, "The overall test program should also include surveillance tests necessary to demonstrate the proper operation of interlocks, setpoints, and other protective features, systems, and equipment required by the technical specifications."' On the basis of the regulatory guidance in place, the staff feels that both the duplication of tests can be avoided and the more technically extensive review and approval required

, for startup tests can be accomplished by writing the detailed core performance startup test procedure such that the surveillance procedure is incorporated to direct data taking and recording. By this method, both regulatory intent to utilize plant procedures and the administrative review, evaluation, and approval controls for startup tests will be included. Because this regulatory position already exists, staff approval of this proposed change would not be necessary.

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3. SIf1PLIFICATION OF THE RECIRCULATION FLOW CONTROL SYSTEM (TEST NO. 27)

The applicant proposed deleting testing of the ALF portion of this system and utilizing experience from other plant startups to modify the cali-bration and testing of the recirculation flow control system to reduce the number of-test points used to optimize control setting and check stable operation.

The staff has discussed and accepted (in Item 1) the delcticn of ALF testing in the Recirculation Flow Control System. The selection of the numDer of test points and their distribution in testing space is a level of detail implementation which does not appear in the FSAR test abstract, but may be reviewed at the Regional level in the detailed test procedure.

Because the requested utilization of experience for bench calibration of controllers to reduce the number of system test points does not change the test objectives, summary test method or acceptance criteria of the test abstract, the staff finds the proposed. changes conceptually acceptable.

As long as the applicant can demonstrate compliance with the acceptance criteria throughout the appropriate system control range, test simplifi-cation is encouraged.

4. & 5. RCIC AND HPCI SYSTEM TESTS (TESTS 12 AND 13)

The applicant proposed deleting tuning of the HPCI and RCIC controllers during the low power testing. Currently, tuning of the controllers for ,

the RCIC and HPCI is perfonned at both low pressure and "near rated reactor pressure. The applicant indicates that testing experience with recently comercialized BWRs h*as demonstrated that a best estimate controller setting may be selected from previous test data and used to bench calibrate the controllers during preoperational testing.. This preliminary bench controller' tuning is sufficient for low pressure testing and final tuning near rated reactor pressure. Experience at previous plants has shown that controller tuning at low pressure condition does not result in optimum performance at higher pressures. The applicant is requesting deletion of controller tuning at the low reactor pressure condition, relying on controller tuning or optimization at or near rated reactor pressure. Testing at low reactor pressure with the rated reactor pressure controller setting will be completed to confirm acceptable, but, perhaps, less than optimized system performance at low pressure conditions.

The staff has reviewed the applicant's requested change to the method of testing these two systems. The staff recognizes that it would be unlikely that operation of these two systems could be optimized over the entire pressure range for which they are expected to operate. Selecting rated pressure conditions for the point of optimization is reasonable and acceptable to the staff because. acceptable operation at low reactor pressure will be confirmed with the rated pressure controller setting.

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6. SELECTED PROCESS TEMPERATURES (TEST N0. 14A)

The applicant is requesting the substitution of the Technical Specification surveillance test for startup of an idle reactor recirculation loop for portions of the selected process temperatures startup procedure and deletion of determination of the low pump speed limit by utilizing a fixed value established from results of this test on previous plants.

The staff has reviewed the applicant's proposed changes and notes that the startup test monitors process temperatures to assure the technical specifi-cations are not exceeded. The staff believes that the technical specifi-cation surveillances accomplish the same purpose. Additionally, the staff notes that testing performed at Limerick and Susquehanna has demonstrated ample margins for stratification.

Accordingly, the staff finds this requested substitution acceptable. The Region staff will confirm during future test procedure review that the surveillance test has been properly incorporated into the procedure and that all necessary test data will be obtained.

The staff found that the request to delete the determination of the low pump speed limit in favor of using a fixed limit derived from previous plant tests was not supported by sufficient information. The applicant supplied additional information on the startup testing for the Brunswick Steam Electric Plant, Unit 1 and Edwin I. Hatch, Unit 2 which was reviewed by the staff. This< information was contained in the Final Summary Report -

Edwin I. Hatch Unit 2 - Startup Test Results, NED0-24734, R. W. Turkowski and W. Yee, October 1979, and Brunswick Unit 1 - Startup Test Results -

Final Summary Report, NED0-24562, J. D. Poppel, November 1977. This additional information and regulation-mandated startup reports of other plants were reviewed and allowed the staff to confirm that a fixed low pump speed limit could be selected (based on previous' plant testing) which assures adequate coolant mixing and, therefore, acceptable temperature differentials in the lower plenum.

7. NATURAL CIRCULATION OPERATION - TEST CONDITION NO. 4 The applicant requested deletion of all testing at Test Condition 4

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(approximately 50% power and 30% core flow) based on the stated premise that the applicant does not intend to operate in this domain of the power / core flow map and that the only way this domain would be approached would be an abnormal operational transient (trip of two recirculation pumps) and resulting natural circulation. The plant technical specifications require that with no reactor coolant system recirculation loops in operation, the operator must take immediate action to reduce thermal power to less than or equal to that allowed by the Core Thermal Power to Core Flow Map within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and, further, the operator must take action to place the plant in at least startup within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Therefore, the applicant states that testing need not be done at Test Condition 4.

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• y The staff felt that the applicant's justification for deleting testing at Test Condition 4 was inadequate. The reactor manufacturer, GE, submitted additional information to supplement the applicant's justification by letter from J. F. Klapproth, GE, to R. A. Becker, NRC, dated November 6, 1985. The staff included this information in addition to the applicant's submission in its review.

The staff finds that the justification for deleting testing at Test Condition 4 is insufficient. The staff considers that the technical specifications define the "possible operating modes," whether or not the applicant foresees their utilization at the commencement of the plant's 40-year life. The length of time allowed at or near natural circulation is long compared to a phenomenon which could generate a safety concern such as stability. The staff agrees with the applicant that the generic natural circulation and stability have been sufficiently confirmed in recent domestic and foreign commercialized BWRs. However, the staff believes the testing encompassed by Regulatory Guide 1.68, Appendix A, Section 5, third introductory paragraph refers to plant specific confirma-tory testing and Test Condition 4 represents one of the " extremes of possible operating modes" referred to in the Regulatory Guide. Therefore, thorough testing dictates equipment specific testing at the natural circu-lation, Test Condition 4 and the staff finds the elimination of testing at Test Condition 4 to be unacceptable.

8. PRESSURE REGULATOR (TEST NO. 20)

The applicant proposed to modify the pressure regulator

• test to:

(a) delete performing this test at Test Condition 4 (TC4), (b) delete the backup pressure regulator takeover testing at TC5, and (c) delete ALF mode tests at TC3 and TC6.

Regarding item (a) above, the staff evaluation of Natural- Circulation Operation - Test Condition No. 4 (Item No. 7 in this safety evaluation) concluded that elimination ~ of testing at TC4 is unacceptable. Accordingly, the proposal to delete testing of the pressure regulator at TC4 is not acceptable.

Regarding item (b) above, the applicant requested the deletion of backup pressure regulator takeover testing at TC5. The system design includes redundant pressure regulators set at slightly different operating pressures.

If the pressure regulator operating at the lower pressure were to fai_l, the higher pressure regulator would assume pressure control. This design function is verified over the spectrum of operating conditions. Currently, this is performed at TC1 through TC6 which cover the power range from low to rated steam flow.

The staff believes that the only variable of concern is total steam flow or, indirectly, plant power level because the pressure regulator maintains fixed pressure for various total flows. For a fixed power level, variation

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6-of core flow would have no impact on the pressure regulator. Examination of the operational power / flow map indicates that TC3 covers a similar but larger power span than TCS and, therefore, provides a redundant test point for testing of~the backup pressure regulator takeover. Because of the redundant nature of this portion of the pressure regulator test at TC5 and TC3, the staff believes that testing of 'the takeover of the backup pressure regulator at TC5 may be deleted without affecting the objectives of the test or loss of confirmation of system performance over the entire operating range.

Regarding item (c) above, the applicant requested deleting all testing associated with the ALF mode of plant operation. This request was addressed and accepted in our review contained in Automatic Load Following (Item No. 1 of this safety evaluation).

9. FEEDWATER SYSTEM RESPONSE TESTING (TEST NO. 21A)

The applicant proposed to modify the Feedwater Control System Test by:

(a) deleting testing at TC4 and (b) deleting ALF-testing.

Regarding item (a), the staff evaluation of Natural Circulation Operation -

Test Condition 4 (Item No. 7 in.this safety evaluation) concluded that elimination of testing at TC4 is unacceptable. Accordingly, the proposal to delete feedwater system response testing at TC 4 is not acceptable.

, Regarding item (b), the applicant has requested deleting all testing ,

associated with the ALF mode of plant operation. This request was addressed and accepted in our review contained in Automatic Load Following (Item No. I of this safety evaluation).

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