ML20070E015

Forwards Update Re Testing Schedule,Scope & Test Parameters for Functional Testing of Alternate Cooling Tower Sys

ML20070E015
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	06/30/1994
From:	Reid D VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BVY-94-69, NUDOCS 9407130316
Download: ML20070E015 (7)

Text

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VERMONT YANKEE l NUCLEAR POWER CORPORATION 1

.f m - Ferry Road, Brattleboro, VT 05301-7002 l ENGINEERING OFFICE s- 580 MAIN STREET

• BOLTON. MA 01740 (508) 779-6711 June 30,1994 BVY 94-69 ,

United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

References:

(a) License No. DPR-28 (Docket No. 50-271)

(b) USNRC to VYNPC Notice of Violation and Proposed imposition of Civil Penalties - Inspection Report No.'s 50-271/93 81 and 93-29, dated 01/21/94 (t) Letter VYNPC to USNRC, BVY 94-18, dated 02/09/94, Raplay to Notice of Violation

Subject:

Description of Functional Testing Planned for the Alternate Cooling System in Reference (c), Vermont Yankee committed to provide an update relative to the testing schedule, scope and the test parameters for functional testing of the Alternate Cooling Tower System. This information is included as Attachment 1.

We trust that this information is sufficient, however, we plan to discuss this test plan with Region I personnel in the near future to ensure any concerns are addressed.

Sincerely, VERMONT YANKEE NUCLEAR POWER CORP.

Donald A. Reid Vice President, Operations cc: USNRC Region i Administrator USNRC Resident inspector - VYNPS USNRC Project Manager - VYNPS 9407130316 DR 940630 i ADOCK 0500 1

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I a VERMONT YANKEE NUCLEAR POWER CORPORATION ATTACHMENT 1 Vermont Yankee has committed to the NRC to perform functional testing of the Alternate Cooling System. The test schedule, scope and test parameters are discussed in this attachment which provides detailed information on the testing to demonstrate that the Alternate Cooling System is capable of meeting its design requirements.

The performance requirements listed in Table 1 have been selected based on the design basis of the Alternate Cooling System. Table 1 is a matrix of the performance issues versus the proposed testing. t SCHEDULE The testing will be completed prior to startup from the next refueling outage presently scheduled in early 1995.

SCOPE AND TEST PARAMETERS Two separate tests will be performed. Descriptions of these tests are as follows:

SW/RHRSW Test Durina Plant Operation (for Hydraulle & Thermal Performance)

The performance capability of the Alternate Cooling Tower Cell will be tested using the normal heat load on the Service Water (SW) system. This test will use the normal service water system alignment except that the SW discharge will be via the Alternate Cooling cell inlet valve (SW-17) and the normal SW discharge to the circulating water system 1 (SW-1). The test will be run with the plant operating at normal power levels and will be initiated by opening SW-17 and then throttling SW-1 as required. j FSAR Section 10.8 restricts the SW discharge path to the circulating water system discharge when the river temperature is 245*F. Flow analyses justifying this test at higher river temperatures have been performed. This flow analysis demonstrates that the required components will receive adequate cooling water with 70*F river water provided the diesel I cooling water discharge from Emergency Diesel Generator (EDG) 'A' is aligned to the new line installed during the 1993 refueling outage and EDG 'B' aligned to the original. This analysis is based on a Design Basis Accident (DBA) with one SW pump operating and the  ;

Non Nuclear Safety (NNS) loads isolated. A safety evaluation and an approved test -

procedure is required prior to performing this test.

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VERMONT YANKEE NUCLEAR POWER CORPORATION ATTACHMENT 1 (Continued)

This testing configuration has several advantages. The first is the test lineup is not signliicantly different than the normal plant lineup. The second is schedule flexibility; i.e., ,

the test can be performed whenever the plant is operating with the river below the maximum I analyzed temperature. However, the test cannot be performed while the circulating water system is aligned to the cooling towers. The third is that the test heat load will be greater than the heat load during a test with the plant shut down.

The performance of the Alternate Cooling cell will be monitored over a flow range of =4000 gpm up to a10,000 gpm which envelopes the design flow of 8000 gpm. The test will demonstrate the thermal performance capability of the cell at various flow rates. The test, ,

along with analyses, will demonstrate system performance as shown on Table 1. It wil! also l provide information to further verify the FLO-SERIES Model. The test will directly demonstrate proper spray distribution pipe flow and will provide additional insight into when, if at all, channeling occurs and the affect of channeling on cell performance. Parameters required to be measured include:

Ambient dry bulb temperature Ambient wet bulb temperature Cell water flow Inlet water temperature Fill outlet water temperature Fan motor amps / volts Distribution box level / flow distribution Flow distribution through fill (external visual inspection)

SW system pressure data SW system flow data RHRSW Basin / Basin Testina Durina Plant Shutdown (for Hydraulic Performance)

This test will be performed using one RHRSW loop while the plant is shutdown. This test will demonstrate RHRSW pump hydraulle and suction capability at maximum loop flow in the Alternate Cooling Mode. The test also demonstrates that a total loop flow of approximately 4500 gpm with a RHRHX cooling water flow of a3400 gpm is achievable and that an RHRSW pump can operate at up to 3000 gpm without cavitation concerns. The test will be performed late in the refueling outage so that decay heat loads are minimized and time to boil is maximized. The testing will not be relied upon to provide cell thermal performance -

8 data due to the low thermal load (=11 x 10 BTU /hr).

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VERMONT YANKEE NUCLEAR POWER CORPOR ATION ATTACHMENT 1 (Continued)

The non-associated SW loop will be operating in the normal lineup to provide required plant cooling water for shutdown cooling and RBCCW cooling. Having one SW loop operable provides for decay heat removal at a positive RHRSW/RHR pressure differential and provides assurance that one EDG will automatically receive required cooling water should a Loss of Normal Power (LNP) event occur while testing. The discharge of both the RHRSW loop in Alternate Cooling and the operating SW loop will be to the basin via the Alternate Cooling cell inlet valve, since there is no valving available to separate the two loops.

Two RHRSW pumps will be operating in the Alternate Cooling loop with flow to the RHRHX (with no RHR flow), RHR Corner Room RRUs, RHRSW Corner Room RRU, and EDG.

RHRSW will not be supplied to the CRD or RHR pumps because of the potential for radiation and chemical cross contamination. These components are normally supplied by a closed cooling water system.

The test will be initiated with the basin at normallevel. Following the required test duration the basin level will be lowered to the calculated seven day level to verify that there is no loss of syphon with the pumps operating and also to verify adequate NPSH.

This test cannot be used to demonstrate adequate inventory due to the available heat load and makeup provided by the operating service water loop. Double isolation valves will be used where possible to reduce the potential for inventory loss due to leakage. Observations for significant leakage will be performed when various SW components / piping are isolated for maintenance with the isolation valves subject to pressure from the operating service water loop.

Parameters required to be measured include:

Basin level Basin water temperature Pump motor amps / volts Pump suction pressure Pump discharge pressure Component flow rates

-Total alternate cooling loop flow rate The performance parameters from the cooling cell performance test will also be taken but are not expected to provide reliable information due to the low heat load.

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VERMONT YANKEE NUCLEAR POWER CORPORATION ATTACHMENT 1 (Continued)

SUMMARY

Based on the testing described above, all system requirements can be demonstrated by test and analyses except for the deep basin inventory. We have determined that there is no testing that can adequately demonstrate this parameter, however, we have conservatively calculated the required inventory and adequate margin exists for one week of Alternate Cooling operation without makeup.

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VERMONT YANKEE NUCLEAR POWER CORPORATION TABLE 1 Notes

1. The suction line was cleaned during the last outage. NPSH testing will verify that no pipe obstruction exists.

2. VYC Calculation 990, Revision 1 evaluated the NPSH of the RHRSW pumps operating in the Alternate Cooling Mode for a wide range of flows and piping conditions.

Although the testing will use only two RHRSW pumps, it will verify the analysis.

During system testing, lowering the basin elevation to approximately the corresponding basin level after 7 days operation will further demonstrate adequate NPSH.

3. Testing will determine if vortexes will form. The grating located above the suction pit will prevent vortexing as long as the basin level remains above the grating. However, lowering the basin elevation to the corresponding basin level after 7 days operation will demonstrate that vortexes do not form.

4. VYC Calculation 990, Revision i demonstrated that the basin level will always be higher than required to maintain pump suction as long as the RHRSW pumps are operating and air is not introduced into the system. However, lowering the basin elevation to the corresponding basin level after 7 days operation will demonstrate that pump suction is not lost.

5. Testing to determine if the pumps can be stopped and then restarted with the basin at the corresponding level after 7 days of operation is not required.

Procedure OP-2181 contains a precaution stating that if the RHRSW pump is secured when in the alternate cooling mode, resumption of flow could be jeopardized if the cooling tower deep basin is not full.

6. The Alternate Cooling System is essentially a split system except for the common suction and common discharge piping sections. Testing one side with both RHRSW pumps operating provides maximum flow for that side. This information coupled with SW flow information and analysis will demonstrate required performance parameters.

7. The test results combined with the FLO-SERIES analysis will demonstrate that pumps hcve required head and components receive required flow.

8. The SW system will not be cross connscied to the RBCCW system due to concerns with spreading tritium from RBCCW system and also chemical contamination of the RBCCW by the SW system.

9. The SW system will also be discharging into the basin during this test which may affect ability to measure flow.

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TABLE 1 .

Performance Requirements Versus Testing -

RHRSW BASIN / BASIN PERFORMANCE REQUIREMENTS PLANT SHUTDOWN SW/RHRSW 1 LOOP PLANT OPERATING COMMENTS A. Hydraulic Requirements

1. Demonstrate RHRSW Pump Suction Capability

a. No pipe obstruction / -

Note 1

b. Adequate NPSH with required pumps / -

Note 2

c. Adequate NPSH at minimum level / -

Note 2

d. Adequate NPSH with allowable fouling / -

Note 2

e. No vortexing at minimum level / -

Note 3

f. No siphon break / -

Note 4

g. Pump restart capability at minimum level / -

Note 5

2. Demonstrate pumps have required head.

a. At 8000 gpm design flow / Note 6 / Note 7

b. At ~4000 gpm / / Note 7

3. Demonstrate proper spray distribution pipe flow. / /

4. Demonstrate required range of system flows.

a. At 8000 gpm design flow / Note 6 / Note 7 P y

b. At ~4000 gpm / / Note 7 1

5. Demonstrate no adverse channeling.

a. At 8000 gpm design flow / Note 9 / -

b. At ~4000 gpm / Note 9 / -

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l TABLE 9 ',.

Performance Requirements Versus Testing -

(Continued)

RHRSW BASIN / BASIN PERFORMANCE REQUIREMENTS PLANT SHUTDOWN SW/RHRSW 1 LOOP PLANT OPERATING COMMENTS f

6. Demonstrate components receive required flow.  !

(See Note 8.)

a. At 8000 gpm design flow / Notes 6 & 8 / Note 6 *

b. At ~4000 gpm / Note 8 / Note 6

7. Demonstrate ability to operate valves. Partial Partial IST Program B. Thermal Pedormance Requirements

1. Tower heat .=9 val capability at required range of i flows.

I

a. At 8000 gpm design flow -

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b. At ~4000 gpm -

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t i C. Inventory Requirements ~

1. Demonstrate inventory loss acceptable - - -

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