ML18052B463

Differential Pressure Test Basis.

ML18052B463
Person / Time
Site:	Palisades
Issue date:	01/15/1988
From:	CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18052B461	List: ML18052B460 ML18052B462 ML18052B463 ML18052B464 ML18052B465 ML18052B466
References
NUDOCS 8801260025
Download: ML18052B463 (9)

Text

Attachment B ATTACHMENT B Consumers Power Company Palisades Plant Docket 50-255 DIFFERENTIAL PRESSURE TEST BASIS January 15, 1988 0001200025 e~g&l,~ 55 PDR ADOCK 0 PDR Pages 8 G

MI0687-2096D-MA05

Attachment B

• DIFFERENTIAL PRESSURE TEST BASIS AUXILIARY FEEDWATER SYSTEM Equipment ID M0-0743, M0-0748, M0-0753, M0-0760 Test Basis The two worst case conditions for operation of the above MOV's are opening the valve after inadvertent closure or closing the valve after a line break downstream. The maximum pressure drop across the valve is developed with

• • P-8A/B on minimum flow and 0 psig in the steam generators. _It is important to note that .the steam generators 'are normally pressurized under accident conditions, greatly minimizing the pressure drop across these valves.

The differential pressure is performed with Auxiliary Feedpump P-8A due to the cold shutdown conditions required for test performance. Steam is required to drive Auxiliary Feedpump P-88, and steam is not available with the plant in cold shutdown. If P-8B is used, the presence of steam in the steam generator will limit the pressure drop across the motor operated valves, which would make the test nonconservative.

Auxiliary Feedpwnp P-8A- develops between 1500 psig and 1540 psig at minimum flow. Relief valve RV-0783 is set at 1565 +/- 15 psig. The test is performed with P-8A on minimum flow, the auxiliary feedwater piping full, and the steam generator at 0 psig. Steam generator level will vary throughout the test, and the effects of steam generator level above the auxiliary feedwater nozzles are ignored as negligible. The maximum steam generator level is 6 feet above the nozzles *

• MI0687-2096D-MA05

2 This test does not meet the CE design pressure drop criteria for these valves, but it does demonstrate operability under the most severe accident conditions.

A hydropump will develop a higher initial pressure drop, but the pressure drop will quickly disappear when the valve begins to open, and very little flow is developed. Using Auxiliary Feedpump P-8A will develop a slightly lower initial

~P, but it will subject the MOV to the continued stresses of stroking under service conditions.

Testing the MOV's with P-8A on minimum flow is representative of the actual accident conditions the valves may see. Draining the discharge piping to increase the initial ,pressure drop across the valve is undesirable due to water hammer considerations. Condensate tank level is maintained at 95 to 100% to maximize Auxiliary Feedpump discharge pressure. Although higher pump discharge pressures may be attained by valving fire protection into the P-8A suction, this is not desirable due to Chemistry concerns. Valving fire protection in is a very cons~ervati ve action that will only be taken in an extreme emergency.

The MOV's are required to close under high flow conditions due to a line break downstream. This is simulated by placing the line in service with full flow through the MOV. While it is not feasible to simulate a line break at the MOV, the test is performed with the steam generator pressure at 0 psig. The valves are cycled one at a time.

Equipment ID M0-0748, M0-0755, M0-0754, M0-0759 Test Basis The two worst case conditions for operation o*f the above MOV' s are opening the valve after inadvertent closure, or closing the valve after a line break downstream. The maximum pressure drop across the valve is developed with P-8C on minimum flow and 0 psig in the steam generators. It is important to note that the steam generators are normally pressurized under accident conditions.

This will greatly minimize the pressure drop across the MOV's.

Auxiliary Feedpump P-8C develops approximately 1275 psig on minimum flow. The test is performed with P-8C on minimum flow, the auxiliary feedwater piping full, and the steam generator at 0 psig. Steam generator level will vary throughout the test, and the effects of steam generator level above the auxiliary feedwater nozzles are ignored as negligible. The maximum steam generator level is 6 feet above the nozzles.

This test does not meet the CE design pressure drop criteria for these valves, but it dows demonstrate operability under the most severe accident conditions.

A hydropump will develop a higher initial pressure drop, but the pressure drop will quickly disappear when the valve begins to open, and very little flow is developed. Using Auxiliary Feedpump P-8C will develop a slightly lower initial pressure drop, but it will subject the MOV to the continued stresses of stroking under service conditions.

MI0687-2096D-MA05

3

• Testing the MOV's with P-8C on minimum flow is representative of the actual conditions the valves may see. Draining the discharge piping to increase the initial pressure drop .across the valve is undesirable due to water hanmer considerations. Condensate ta.nk level is maintained at 95 to 100% to maximize Auxiliary Feedpump discharge pressure. Although higher pump discharge pressures may be, attained by valving service water into the P-8C suction, this is not desirable due to Chemistry concerns. It is also a very conservative action.

The MOV's are required to close under high flow conditions due to a line break downstream. This is simulated by placing the line in service with full flow through the MOV. While it is not feasible to simulate a line break at the MOV, the test is performed with the steam generators at 0 psig. The valves are cycled one at a time.

HIGH PRESSURE SAFETY INJECTION SYSTEM Equipment ID:

M0-3007, 3009, 3011, 3013, 3062, 3064, 3066, 3068 TEST BASIS:

The two worst case situations for operation of the above listed MOV's would be either when a valve is required to be reopened after inadvertent closure or closed under high flow conditions due to a break downstream. In the case where the valve is required to be reopened, the maximum differential pressure would be with the pump operating on miniflow and all HPSI MOV's closed. This would give approximately 1235 psig upstream of the valve, HPSI shutoff head minus elevation difference. On the downstream side of the valve the pressure would be the head of water between the valve (572' elevation) and the PCS piping.

This head of water would exist in a post-accident situation or the piping would not be intact and the valve would not be reopened.

When the PCS is on shutdown cooling with the hotleg drained to 617' 6" and LTOP requirements met we have the same water level conditions we would have in a post-accident situation. In fact the test conditions exceed post-accident conditions because the PCS would be at some pressure higher than atmosphere reducing the t.P. In the above referenced letter it was proposed to test these valves using a charging pump to a pressure of 1245 psig. Since T-249 tests the valve under a.ctual post-accident conditions there is no need to test at higher pressures. Also this test will simulate the actual conditions of opening through the entire stroke where as with the charging pumps, do to their limited flow capacity, would offer no resistance to opening once the valve is cracked open. The charging pump also does not allow for testing the valve in its design direction to isolated flow to one. of the PCS cold legs in the event the break is there. Test T-249 will test the valves under worst case closing conditions to verify proper operation in both the open and closed directions.

MI0687-2096D-MA05

4

• • Eguipment ID:

M0-3082 and M0-3083 TEST BASIS:

M0-3082 and M0-3083 would operate approximately five hours after an accident.

These valves are interlocked with M0-3080 and 3081 respectively and would only be operated with one HPSI (RHPSI) open. Therefore test T-249, with the system conditions specified, will test these valve under conditions at least as severe as would exist in a post-accident situation. With one HPSI or PHPSI valve open the pump discharge pressure should be approximately 950 psig. Downstream of the valve to the PCS piping. This head of water would exist in a post-accident situation or the piping would not be intact and the valve ~ould not be opened.

When the PCS is on shutdown cooling with the hotleg drained to 617 1 6" and LTOP requirements met we have the same water level conditions we would have in a post-accident situation. In fact the test conditions exceed post-accident conditions because the PCS would be at some pressure higher than atmosphere reducing the ~P. In the above referenced letter it was proposed to test these valves using a charging pump to a pressure of 1245 psig. Since T-249 tests the valve under actual post-accident conditions there is no need to test at higher pressures. Also this test will simulate the actual conditions of opening through the entire stroke where as with the charging pumps, due to their limited flow capacity, would offer no resistance to opening once the valve is cracked open. This test has the added advantage of testing the ability of these valves to close under full flow condition in the event the valve is required to close.

Eguipment ID:

M0-3080, M0-3081 TEST BASIS:

M0-3080 and M0-3081 would operate approximately five hours after an accident.

These valves are interlocked with M0-3082 and 3083 respectively and would only be operated with one HPSi (RHPSI) open. Therefore test *T-249 with the system conditions specified will test these valves under conditions at least as severe as would exist in a post-accident situation. As indicated in WJA86*007 the ~p that these *valves would see in either the open or closed direction is small and therefore should not require testing. Since the valves are interlocked with M0-3082 and M0-3083 and will be moved during testing they.will be checked for proper operation in the open and closed direction *

• MI0687-2096D-MA05

RGURE 1 TYPICAL STEM THRUST AND CONTROL SWITCH ACTUATION SIGNATURES

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