ML20034A761
| ML20034A761 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 04/11/1990 |
| From: | Sears P Office of Nuclear Reactor Regulation |
| To: | Papanic G YANKEE ATOMIC ELECTRIC CO. |
| References | |
| GL-89-04, GL-89-4, TAC-74802, NUDOCS 9004240234 | |
| Download: ML20034A761 (10) | |
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Aprill 11, 1990
'I Docket No. 50 029 Mr. George Papanic, Jr.
Senior Project Engineer Licensing Yankee Atomic Electric Company 580 Main Street Bolton, Massachusetts 01740 1398 Dear Mr. Papan*-
SUBJECT:
SAFETY EVALUATION REPORT: INSERVICE TESTING-(IST) PROGRAM CHANGES. YANKEE R0WE NUCLEAR STATION (TAC NO. 74802)
By letter dated October 3,1989, you submitted the revised IST program for Yankee Rowe Nuclear Station. The submittal is primarily in response to NRC Generic letter 89-04, but contains three new relief requests.
You requested NRC's evaluation of the three relief reouests since they are outside the scope of the Generic Letter positions.
The staff with technical assistance from EG&G Idaho Inc., has reviewed the three relief requests in accordance with the requirements of 10 CFR 50.55a and NRC Generic letter positions and finds them acceptable. The bases of the staff's findings are provided in the enclosed EG&G technical evaluation report.
Sincerely, Original signed by Patrick M. Sears, Project Manager Project Directorate 1-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
i As stated cc: See next page 0
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t Document Name: YANKEE R0WE TAC NO. 74P02
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5 Mr. George Papanic, Jr.
Yankee Rowe I
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Dr. Andrew C. Kadak, President and Chief Operating Officer i
Yankee Atomic Electric Cempany 580 Main Street Bolton, Massachusetts 01740-1398 l
Thomas Dignan, Esquir6 Ropes and Gray
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225 Franklin Street Ecston, Massachusetts 02110 Mr. T. K. Henderson Acting Plant Superintendent Yankee Atomic Electric Company Star Route
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Powe, Massachusetts 01367 F.esident inspector Yankee Nuclear Power Stetion U.S. Nuclear Regulatory Comission Post Office Box 28 Mcorce Bridge, Massachusetts 01350 Regional Administrator, Region I l
U.S. Nuclear Regulatory Coumission 475 Allendale Road i
King of Prussia, Pennsylvania 19406 Robert P. Hallisey, Director Radiation Control Program Massachusetts Department of Public Health 150 Treennt Street, 7th Floor Boston, Massachusetts 02111 Mr. George Sterzinger Comissioner Verront Department of Public Service 120 State Street, 3rd Floor Nontpelier, Vermont 05602 Ms. Jane M. Grant Senior Engineer - PLEX Licensing Yenkee Atomic Electric Company 580 Main Street Bolton, Massachusetts 01740-1398 t
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DISTRIBUTION EN NRC & Local PDRs PD I-3 r/f S. Varga B. Boger MRushbrook R. Wessman P. Sears OGC E. Jordan ACR3(10)
PD plant-specific file J. E. Richardson A. Gody i
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7 Enclosure l'
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TECHNICAL EVALUATION OF RELIEF REQUESTS i
3 YANKEE R0WE NUCLEAR POWER STATION
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PUMP AND VALVE INSERVICE TESTING PROGRAM i
F This report documents EG&G Idaho's review of three new or revised relief requests submitted by Yankee Atomic Electric Company for their Yankee Rowe Nuclear Power Station Pump'and Valve Inservice Testing (IST). Program, as described in and forwarded to the NRC by a letter dated.0ctober 3,1989.
i The three new relief requests were evaluated utilizing the criteria and guidance' contained in the the Code of Federal Regulations 10 CFR 50.55a and Generic Letter 89 04, " Guidance on Developing Acceptable Inservice Testing l
Programs." Relief was recommended where it was determined that the request adequately meets one or more of the following criteria:
The proposed alternative provides a level of quality and safety
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essentially equivalent to that afforded by the Code required testing.
Testing the affected components in accordance with the Code requirements l
1s impractical and the proposed testing provides adequate assurance of-i operational readiness.
Testing the affected components in accordance with the Code requirements would place an unreasonable burden on the licensee without a compensating increase in safety and the proposed alternative testing provides adequate assu.rance of operational readiness.
Relief Reauest Evaluations The Yankee Atodiic Electric Company basis for requesting relief from the Code testing requirements and the reviewer's evaluation of that request is summarized below for the identified relief requests.
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R'elief Recuest No. 1 4
4 Relief Reouest.
The licensee has requested relief from the monthly pump testing requirements of the 1977 Edition through Summer 1978 Addenda of I
Section XI, Paragraph IWP 3400, for all pumps in the IST program.
The licensee has proposed adopting the 1980 Edition through Winter 1980 Addenda of ASME Section XI for pump testing.
i Licensee's Basis for Recuestina Relief--As indicated in your letter dated May 24, 1989, Yankee is currently committed to ASME Section XI, 1977 Edition, Summer 1978 Addendum for Inservice Testing of pumps and valves.
This edition of the Code requires monthly testing of pumps to monitor
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hydraulic characteristics.
I Later editions of the Code recognize,that pump operability / readiness can
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be adequately demonstrated through quarterly testing.
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Based on the above, Yankee proposes to adopt ASME Section XI 1980 l
Edition, Winter 1980 Addendum for pump testing.
Once approved, it is l
Yankee's intention to adopt this edition of the. Code in its entirety for pump
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testing until the expiration of the current interval.
L Valve testing will continue to be conducted in accordance with ASME Section XI 1977 Edition, Summer 1976 Addendum, c
Evaluation--Later editions of the Code allow quarterly versus l
monthly pump testing to fulfill-IST program requirements.
Industry and NRC.
l experience has shown that quarterly pump testing is sufficient to detect degradation and assure the operability of these safety related pumps.
The licensee has proposed adopting the requirements of t b 1980 Edition, through Winter 1980 Addenda, of Section XI of the ASME Code, in its entirety for all l
l IST pump testing.
The.NRC has accepted the requirements of this edition of the Code as adequate for providing reasonable assurance of operational readiness.
Therefore, the licensee's proposal to follow the 1980 Edition, through Winter 1980 Addenda, is acceptable.
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il Based on the determination that the proposed testing would provide an-acceptable level of quality and safety, relief may be granted as requested, i
Relief Reauest No. 2 Relief Recuest.. The licensee has requested relief from the corrective I
action requirements of Section XI. Paragraph IWV 3413, for all power operated valves. The licensee has proposed comparing measured valve stroke times to specified reference values instead of the previous stroke times.
Licensee's Basis for Reouestino Relief-Measuring changes in stroke time from a reference value as opposed to measuring changes from the previous test is a better method of testing power operated valves.
Regarding comparison of stroke times for power operated valves (IWV 3413), Yankee will compare the stroke time to a specified reference value instead of the previous inservice test.
This proposed alternative examination has been recognized as an acceptable test method in Generic i
Letter 89 04 for valves with stroke times less than (10) seconds.
-t Evaluation -Using a reference or average value of valve stroke time for comparison of test data versus the previous stroke time is an acceptable alternative to the Code requirements and has been endorsed by NRC Generic Letter No. 89-04, " Guidance on Developing Acceptable Inservice Testing Programs." While still being in compliance with the Code, a continual increase in valve stroke time over a long period could result in significant valve degradation without the test frequency being increased or corrective action being taken.
This is because the test data is compared on y to the previous stroke time and each incremental increase in stroke time could be less than that specified in Paragraph IWV-3417(a).
Comparing test results to a reasonably derived reference, or average stroke time, insures that earlier i
attention will be given to the valve as stroke times increase substantially l
from the reference value.
The licensee's proposed alternative is, thereb re, an acceptable alternative to the Code requirements.
However, the reference value of stroke time used for comparison of test data should be established
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9n a consistent basis when the valve is known to be in good operating I~
condition, ip The licensee's proposed alternative method of determining reference stroke time values provides an acceptable level of quality and safety in terms of meeting the intent of IWV-3417, to monitor st:oke time increase take necessary corrective actions and is, therefore, acceptable.
n Pelief Recuest No. 3 Relief Reouest.
The licensee has-requested relief from the monthly pump testing requirements of the 1977 Edition through Summer 1978 Addenda of Section XI, Paragraph IWP 3400, for the shutdown cooling pump, P 19 licensee has proposed testing this pump during cold shutdowns a The outages.
ticensee's Basis for Recuestino Relief--The shutdown cooling pum (P-19) is used to cool the main coolant system from 330 F to 140 F or 0
0 less during plant cooldowns.
The only testing circuit available to supply a positive suction head to the pump.for monthly inservice testing is tak suction from and discharging to the low pressure surge tank.
The low pressure surge tank (LPST) functions during plant-operation provide a surge volume for main coolant system (MCS) volume control LPST receives letdown flow from the MCS and is the suctio The charging back to the MCS.
In addition, it provides the source for flow through ion exchangers which maintain primary water quality.
During power operation, mixing between the LP'T and the MCS S
and letdown operation maintains the LPST boron concentration in equili with the MCS.
Inventory additions to the LPST are carefully controlled to maintain this equilibrium.
Any disturbance in the LPST boron concentration will result in a change in the MCS boron concentration via charging and letdown operation.
Changes in MCS boron concentration require compensating action by plant operators to maintain steady state power operation.
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The boron concentration in the shutdown cooling system piping is I
9 significantly greater (several hundred ppm) than the LPST concentration Mixing of this water with the LPST inventory as a result of shutdo pump testing would dramatically change the LPST boron concentration and to charging and letdown operation, result in undesirable changes in core
, due reactivity to which the operators would have to respond.
The only means available to preclude test induced reactivity cha would be to halt charging and letdown operation for both the duratio test and a sufficient post-test time interval to equilibrate the LPST boro{
concentration.
Iterative sampling and LPST makeup operations would be required to accomplish this, it is expected that several hours would.be required to perform these actions in a manner which assures that ste i
power operation is maintained.
This would result in an extended loss of normal charging and bleed operations.
Testing of the shutdown cooling pump during power operation is impractical because it wculd result in the loss of the normal volum function of the low pressure surge tank, As an alternative to monthly testing, the shutdown cooling pump t
tested during cold shutdowns and refueling outages.During this testing the Code required parameters of flow, differential pressure, vibration lubrication will be observed and measured.
, and Testing the pump at this time
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will also allow the pump to operate at normal temperatures, pressures t
flow rates providing more accurate and useful performance data
, and Evaluation--The only flow path for testing this puinp during po operation takes suction from, and discharges to, the LPST.The shutdown cooling system boron concentration is significantly higher than th boron concentration.
Recirculation of the 1.PST water with the shutdown cooling pump to accomplish pump testing would increase the boron concentration of the LPST.
Since the LPST serves as a suction source for charging pumps, performing this testing with the system in its would cause an increase in the MCS boron concentration.
This would result in a reactivity transient which could cause a plant trip.
Power operation 5
4 p
"without charging or letdown flow would be a complex evolution.
However, this abnormal plant lineup would have to be maintained for a considerab
.o' of time while the shutdown cooling pump is tested and the LPST boron concentration is reestablished at the necessary value.
This undesirable lineup could result in a disruption of MCS chemistry control since the purification system would not be available and could also result in a loss pressurizer level control.
Additionally, this testing flow path is not equipped with flow instrumentation.
Therefore, the flow rate measurements required by the Code could not be obtained without system modifications.
The unplanned shutdowns which could arise due to this testing during power operation and the system modifications necessary for the installation of flow rate instrumentation would be burdensome for the licensee d involved.
The shutdown cooling system is used d,uring cold shutdowns' an outages to remove reactor decay heat.
Testing can be accomplished at this time and all Code required parameters can.be measured.This testing should provide reasonable assurance of operational readiness.
Based on the determination that performing pump testing at the Code required frequency is impractical, that the licensee's proposed alternativ would provide reasonable assurance of operational readiness, an j
the burden on the licensee if Code requirements were imposed, rel granted as requested.
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Page No.
I Jv Of/29/90 YANKEE ROWE NUCLEAR POWER STATION ij TABLE 1
SUMMARY
OF REllEF REQUESTS i
REllEF SECTION XI EQUIPMENT ALTERNATE ACTION REQUEST' REQUIREMENT IDENTIFICATION METHOD OF BY NUMBER
& SUBJECT TESTING USNRC i
Pump IWP-3400 Pump All pumps in Pump testing will be Relief Granted I
1 testing the IST conducted quarterly (a)(3)(1) j frequency.
program in accordance with the 1980 Edition of the Code.
Valve IWV 3413 All power Stroke times will be Relief Granted 2
Compare valve operated compared to (a)(3)(1) stroke time to valves specified reference previous stroke strpke times, time
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measurement.
Pump IWP-3400 Pump Shutdown Pump will be tested Relief Granted 3
testing cooling pump, during cold (g)(6)(i) frequency.
P 19 shutdowns and refueling outages.
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