ML17341A205
| ML17341A205 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 06/08/1981 |
| From: | Carfagno S FRANKLIN INSTITUTE |
| To: | Butcher E NRC |
| Shared Package | |
| ML17341A207 | List: |
| References | |
| NUDOCS 8106110366 | |
| Download: ML17341A205 (21) | |
Text
G0l d TQR Y' "JFCIRH dT In'il 0TSTR TB'JT ION S YSTEH (R I OS)
ACCESS IO~ij NBR: 8106110366 DOC ~ OATE: 81/06/08 NOTARIZED:
NO FACIL:50-250 Tur key Point Plant.
Uni t 3> Florida power and Liant C
50-251 Tvr<ey Point Pla~ti Unit ai Florida Power and Light C
AUTH'AME AUTH@9 AFF fl IATIQN CARFAGNOp 5 ~ P ~
Franklin Insti tute/Frank 1 in Research Center RECI P ~ NA"E RECIPIENT AFFILIATION BUTCHER,ED J.
NRC No Detailed Affiliation Given
SUBJECT:
Forwards "Containment Leawane Rate Testinai" technical evaluation rept'TSTRTBJTION COPE:
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TITLE: Fran'k 1 in Research Center Contract Repor t NOTES:
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(H IJ( Franklin Research Center A Division of The Franklin institute June 8,
1981 Attention:
Mr. E. J. Butcher, Jr.
(MS 416)
Project Officer U.S. Nuclear Regulatory Commission Washington, D.C.
20555 e
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Reference:
FRC Project C5257 NRC Contract NRC-03<<79-118 NRC TAC No. 08779/08780 FRC Task No. 53/54
Title:
Technical Evaluation Report for Turkey Point Units 3 and 4; Containment Leakage Testing
Dear Mr. Butcher:
The Technical Evaluation Report (TER) for Turkey Point Units 3 and 4 is hereby forwarded.
This report is forwarded in accordance with telephone conversations between Mr. T. J.
DelGaizo (FRC) and Mr. P. Hearn (NRC/CSB) on April 21, 1981 and April 27, 1981.
Submission of this TER represents FRC's final action on Tasks 53 and 54.
Very truly yours, S.
P. Carfa o
Project Manager TJ D/SP C/bg Encl.
cc:
J.
Shapaker P.
Hearn Y. Huang goo i/(
820e gtog(Q, The Benjamin Franklin-Parkway, Philadelphia: Pa. 19103 (215) 448-'1000 TWX-710 670 1889
TECHNICAL EVALUATIONREPORT CQNTAlNMENTLEAKAGE RATE TFSTlNQ FLORIDA PCNER a LICHT KPPNY
~
TUQUE POINT UNITS 3 ID 0 NRC DOCKET NO.
50-250, 50-251 NRC TAC NO.
- 08779, 08780 NRC CONTRACT NO. NRC43-79-118 FRC PROJECT C5257 FRC TASK 53I54 Prepared by Franklin Research Center The P'arkway at Twentieth Street Philadelphia, PA 19103 Authar:
T. J. DelGaizo FRC Group Leader:
T. J. DelGaizo Prepared for Nuclear Regulatory Commission Washington, D.C. 20555 Lead NRC Engineer:
Y. s.
Huans June 5,
1981 This;report was prepared as an. account of work sponsored. by an agency of the United States~Government.
Neither the United States Government nor any agency thereof, or any of their employees, makes-any warranty; expressed or implied, or assumes any legal, liabilityor responsibility for any third party's use, or the. results of such
- use, of any Information, apparatus, oroduct or process disclosed ln this report, or represents that Its use by such third party would not infringe privately owned rights.
Franklin Research Center.
A'ivision of:The: Franklin. Institute.
The Benlamin~Franldin Parkwoyg Phiial. Pa:: l9103'(215) 448-'l0001
TER-C5257-53/54 CONTENTS Section Title Pacae BACKGROUND EVALUATION CRITERIA TECHNICAL EVALUATION 3.1 Request for Exemption From the Requirements Appendix J of 10CFR50, 3.1.1 Testing of Containment Airlocks 3.2 Proposed Technical Specification Change 4
CONCLUSIONS REFERENCES APPENDIX A - Extrapolation of Reduced Pressure Leakage Measurements to Equivalent Full Pressure Leakage 4
00 Franklin~Research>Center AOlvlsbn diThe Ftankln IroSute~
TER-C5257-53/54 1.
BACKGROUND On August 7, 1975 [1], the NRC requested Florida Power a Light Company (FPL) to review the containment leakage testing programs at Turkey Point Units 3 and 4 and to provide a plan for achieving full compliance with 10CFR50, Appendix J, including appropriate design modifications, changes to Technical Specifications, or requests fo exemption from the requirements pursuant to 10CFR50.12, where necessary.
FPL responded on September 12, 1975 [2], stating that the containment leakage testing program at Turkey Point Units 3 and 4 conformed to the requirements of Appendix J except for the frequency and method of testing containment airlocks, the freouency of performing Type B electrical penetration leak tests, and minor differences in terminology between the Technical Specifications and Appendix J.
FPL indicated that the minor differences in terminology were eliminated by its proposed Technical Specification change of September 20, 1974 [3].
FPL's letter of July 27, 1977
[4) provided additional information regarding proposed testing of containment airlocks.
This letter also indicated that Type B electrical penetrations would be tested every refueling
- outage, leaving the question of testing of containment airlocks as the only remaining request for exemption from the requirements of Appendix J.
The purpose of this report is to conduct, technical evaluations of out-standing issues regarding the implementation of 10CFR50, Appendix. J, at Turkey Point Units 3 and 4'.
Consequently, technical evaluations, are provided'or FPL's request for exemption from the requirements: of Appendix; J. regarding, the testing of; containment airlocks: as, submitted, in Ref'erences 2and 4, as; well, as a proposed revision to Technical Specification 4.4.2 submitted in Reference 4.
lllj Franklin. Research~Center A~ diThe frankln Ir>>ltutc
TERM5257-53/54 2.
EVALUATION CRITERIA Code of Federal Regulations, Title 10, Part 50 (10CFR50),"Appendix J, Containment Leakage Testing, provided the criteria used in conducting the technical evaluations.
Where applied to the following evaluations, the criteria are either referenced or briefly stated, where necessary, in support of the results of the evaluations.
Furthermore, in recognition of the plant-specific conditions that could lead to requests for exemption not explicitly covered by the regulations, the NRC directed that the technical reviews con-stantly emphasize the basic intent of Appendix J, that potential containment atmospheric leakage paths. be identified, monitored, and maintained below estab-lished limits.
I)(l FranMin~ Research~ Centen AOrson d iThe Fcanlln Insole<<
TERM5257-53/54 3.
TECHNICAL EVALUATION 3.1 REQUESTS FOR EXEMPTION FROM THE REQUIREMENTS OF 10CFR50g APPENDIX J 3.1.1 Testing of Containment Airlocks In Rererence 2,'PL requested an exemotion from the requirements of
- 10CFR50, Appendix J with regard to the testing frequency and method of testing containment airlocks.
This exemption request would permit continued testing in accordance with Turkey Point Techn'cal Specification 4.4.2.2, which required pressure testing of the personnel and emergency airlocks either annually, if not used, or every 4 months if used periodically.
FPL's basis for this request was given as follows:
Personnel and emergency airlocks are leak tested in accordance with Turkey Point Operating Procedure 13514.1.
Leak tightness of the inner door is tested by pressurizing the annulus between the two 0-rings.
The outer door 0-rings are then tested by pressurizing the entire airlock.
However, since the inner door ooens into containment, both tests tend to unseat the inner door.
Therefore, if the inner door 0-rings are to be meaningfully
- tested, the door must be held shut by a clamping arrangement which takes a minimum of about 12 man-hours to install.
A similar arrangement is not required on the outer door because that door opens into the airlock and the test differential pres-sure is in the direction which seats the door.
- Thus, a simple positive-pressure test of the personnel and emergency airlocks is not possible because of the design and arrangement of the doors.
Both containments are entered approximately once each week for performance of routine inspections and minor, maintenance.
If we were to perform. the inspection program required by Operating, Procedure 13514.1 after each, airlock-opening,. routine. entry of the containment would. become impractical. due to the many man-hours which would be. necessary for leak testing.
Therefore, in order to continue a viable containment inspection program, and at the same time achieve compliance with the intent of Appendix J,
we submitted a proposed Technical Specification change on September 20,
- 1974, which provided for the performance of an 0-ring vacuum test instead of a pressure test.
"We have designed and built a vacuum test device which could be duplicated and permanently installed on all airlock outer. doors and. used to (l!I Franklin Research Center A Dlvtslon d iThe Frenkln Inslete~
TER-C5257-53/54 leak test the doors after each ooening.
Pending disposition of the proposed
- change, however, we are currently complying with the existing Technical Specification 4.4.2.2 requirement which requires airlock testing once every 4 months.
In Reference 4,
FPL withdrew its request for exemption with regard to the frequency of testing airlocks, but continued to request an exemption in order to use the vacuum testing technique to verify airlock door seals after each opening.
In this letter, FPL provided a revised Technical Specification 4".4.2.2 which required airlocks to be tested as follows:
4 ~ 4 ~ 2 LOCAL PENETRATION TESTS Test Procedure and Frequency Local leak detection tests of the following components shall be performed at a pressure not less than 50 psig using pressure
- decay, soap bubble, halogen detection or equivalent'methods at. the frequency listed, unless other-wise noted:
2.
Personnel and Emergency Airlocks a.
Within 3 days of every first of a series of openings when containment integrity is required, verify that door seals have not been damaged or seated improperly by vacuum testing the volume between the door seals in accordance with approved plant procedures.
b.,
At least once per
- 6. months, conduct an overall airlock leakage test to verify that the overall
.airlock leakage rate is. within its limit.
FRC Evaluation:
Sections III.B;.2. and III'.D.?'f Appendix J require that containment air-locks be tested at peak calculated accident pressure (Pa) at 6-month intervals and after each opening in the interim between 6-month tests.
These require-ments were imposed because airlocks represent potentially large leakage paths which are more subject to human error, than other containment penetrations.
Type B penetrations (other than airlocks) require testing in accordance with Appendix. J at intervals not to exceed
- 2. years.
l]ll Franklin~Research.Center, A DMske d:Tbc Ftanl4n Insole~
TER-C5257-53 54 Appendix J was published in 1973.
A compilation of airlock events from Licensee Event Reports submitted since 1969 shows that airlock testing in accordance with Appendix J has been effective in the prompt identiri 'ation of airlock leakage, but that rigid adherence to the after-each-opening requirement may not be necessary.
Since
- 1969, there have been approximately 70 reported airlock 'kage tests in which measured leakage exceeded allowable limits.
Of these
- events, 25% were the result of leakage other than from improper seating of airlock door seals.
These failures were generally caused by leakage past door-operating mechanism handwheel packing, door-operating cylinder shaft seals, equalizer valves, or test lines.
These penetrations resemble other Type B or C contain-ment penetrations except that they may be operated more frequently.
Since air-locks are tested at a pressure of Pa every 6 months, these penetrations are
- tested, at a: minimum,, four times more frequently than typical Type B or C pene-trations.
The 6-month test is, therefore, considered to be both justified and adequate for the prompt identification of this leakage.
Improper seating of the airlock door seals, however, is not only the most frequent cause of airlock failures (the remaining 75%), but also represents a
potentially large leakage path.
While testing at a pressure of Pa after each opening will identify seal leakage, it can also be identified by alternative methods such as pressurizing between double-gasketed door seals (for airlocks designed with this: type of seal) or pressurizing the: airlock to pressures, other. than Pa.
Furthermore, experience gained in testing airlocks since. the issuance of Appendix J'ndicates'hat the; use of, one: of these alternative methods. may. be. preferable to the full-pressure test of the entire airlock.
Reactor plants. designed prior: to the issuance of Appendix J'ften do not.
have the capability to test airlocks at Pa without the installation of strong-backs or the performance of mechanical adjustments to the operating mechanism of the inner doors.
The reason for this is that the inner doors are designed to seat with accident pressure on the. containment side of the door, and there-fore, the operating mechanisms were not designed to withstand accident pressure in the opposite direction.
When the airlock is pressurized for a local airlock 00, FranMin Research~ Center A OMske oui'ihe FrankSn Induce>
TER-C5257-53/54 test (i.e., pressurized between the doors),
pressure is exerted on the airlock side of the inner door, causing the door to unseat and preventing the perfor-mance of a meaningful test.
The strongback or mechanical adjustments prevent the unseating of the inner door, allowing the test to proceed.
The installa-tion of strongbacks or performance of mechanical adjustments is time consuming (often taking several hours),
may result in additional radiation exposure to operating personnel, and may also cause degradation of the operating mechanism of the inner door, with consequential loss of reliability of the airlock.
In
- addition, when conditions require frequent openings over.a short period of time, testing at Pa after each opening becomes both impractical (tests often take from 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to several days) and accelerates the rate of exposure of personnel and the degradation of mechanical equipment.
For these
- reasons, the intent of Appendix J is satisfied, and the undesirable effects of testing after each opening are reduced if a satis-factory test of the airlock door seals is performed within 3 days of each opening or every 3 days during periods of frequent openings, whenever containment integrity is required.
The test of the airlock door seals may be performed by pressurizing the space between the double-gasketed seals (if so equipped) or by pressurizing the entire airlock to a pressure less than Pa that does not: require the installation of strongbacks or performance of other, mechanical adjustments.
If the reduced pressure airlock test is to be employed:,, the results of, the: leakage. test must be conservatively extrapolated to equivalent Pa, test results.
In viewi of the foregoing discussion, FPL's. proposed, Technical Specification 4'.4'.2'..2, is. acceptable;,
Furthermore, no exemption from the requirements; of Appendix. J is, necessary because FPL's proposed testing is within the revised: version of: Section III.D.2 (effective October 22,,
1980).
FPL should ensure that its airlock testing program is in complete conformance with the revised rule.
With regard to the extrapolation of the reduced pressure test to equivalent Pa test results, comments on FPL's proposed extrapolation method submitted on November 26, 1980
[5] are contained. in Appendix. A to this report'.
(!L
. Franklin:Research'enter, holvblon diTbe r tsnkln lnsautei
I TER-C5257-53/54 3.2 PROPOSED TECHNICAL SPECIFICATION CHANGE In Reference 4,
FPL proposed to revise Specification 4.4.2 to incorporate its proposed exemption from Appendix J with regard to the testing of contain-ment airlocks.
In addition, this specification provided for testing at Pa using pressure
- decay, soap bubble, halogen detection, or equivalent methods of the following components:
Containment purge valves each refueling Equipment access openings - annually and after use Fuel transfer tube flange - each refueling Electrical penetrations each refueling.
The proposed specification also, required that repairs and tests be made.
whenever the sum of the local leak rate tests, including isolation valves, exceeds 60% of the total containment allowable leak rate.
FRC Evaluation:
In Section 3.1 of this report, FRC found FPL's proposal for testing of containment airlocks to be acceptable, provided that the results of the vacuum testing between airlock door seals are conservatively extrapolated to Pa results.
The remainder of the proposed specification conforms to Section III.B of Appendix J.
Consequently, Proposed Specification 4.4.2 is acceptable in meeting the requirements and intent of Appendix J.
l)l) Franklin Research:Centerr r h OMsion diIhc Frsnl4n Induce.
TER-C5257-53/54 4 ~
CONCLUSIONS FPL's request for exemption from the requirements of Appendix J regarding testing of containment airlocks as submitted in References 2 and 4 and FPL's proposed change to Technical Specification 4.4.2 as submitted in Reference 4
were technically evaluated.
The conclusions of these evaluations are as follows:
0 FPL's proposal to verify that airlock door seals have not been damaged or seated improperly by vacuum testing the vo'lume between the seals within 3 days of every first of a series of
- openings, when containment integrity is required in the interim between full-pressure 6-month, tests is acceptable.
No exemption is required because of the revision to Section ZIZ.D..2, effective October 22, 1980.
0 FPL's proposed change to Technical Specification 4.4.2 is acceptable since it conforms to the requirements of Appendix J.
00 FrankliniReeseerch Center.
A Olvbkon d iThe Ftsnkln Insdtu(e~
TER-C5257-53/54 5 ~
REFERENCES 1.
K. R. Goller (NRC)
Letter to FPL August 7 < 1975.
2.
R.
E. Uhrig (FPL)
Letter to K. R. Goller,(NRC)
September 12, 1975.
3.
R. E. Uhrig (FPL)
Letter to E. G. Case (NRC)
September 20, 1974.
4.
R. E. Uhrig (FPL)
Letter to V. Stello (NRC)
July 27, 1977.
5.
R. E. Uhrig (FPL)
Letter to S'. A. Varga (NRC)
November: 26, 1980.
()(),FrankliniReesearch Center' AOMsioediThe Ftsnl4n Instate
TER-C5257-53/54 APPENDlX A EXTRAPOLATION OF REDUCED PRESSURE LEAKAGF MEASUREMENTS TO EQUIVALENT FULL PRESSURE LEAKAGE 1.
FPL's CORRELATION In Reference 5,
FPL provided the following information:
"The test will begin at a absolute pressure of 12.92" Hg (17" Hg vacuum) and alarm if pressure increases to 14.42" Hg (15.5" Hg vacuum).
To determine the leak rate at 50 psig (64.7 psia),
the design basis accident pressure, the following derivation was used:
Flow for a compressible fluid may be calculated as follows:
F ~
K Y ~hP where F = Flow or leakage K = Coefficient of resistance Y ~ Expansion factor hP. ~ Pressure drop across. seal The maximum valve for Y is 1.0 and calculates the leakage for a non-compressible fluid.
The coefficient of resistance is constant for each seal tested.
Therefore:
F=K~hP or L=KJhP A ratio between the leak rate at L5p and Ltest becomes:
L5p K
P64.7
- test, 14'.,7 P14.7 Ptest L50~'Ltest,P64, 7 - P14,.7 14.,7'es t, where'64
~ 7' 131 ~73"'g:
P14
~7'9. 92"'g, L5p = Ltest 131~73 29'2 29.92 -. Ptes t-1Chemical. Engineer,'s
- Handbook, McGraw-Hill, Inc.,
1963, Section 5 (Fluid Mechanics:,
Flow Measurement),
Pages:
5-8! & 5'-9>
00, Franklin. Research: Center.
A Ovben otiThe Fnnl4n Insane
-10:--
TER-C5257-53/54 Lgp J 102,52 Ltest 29.92 Ptest Lso
~
10.13 Ltest 29.92 -
Ptest with pressures in inches of Hg" By substituting 12.92 in.
Hg for P
, this formula yields the following test'orrelation:
2.45 Lso Ltest EVALUATION:
The Licensee dropped the value of Y from the formula F ~ KY JhP because the maximum value of Y's 1.0.
If-the value of Y is retained, the correlation would be:
L50 KY50 P64.7 P14.7 test test'4.7 test Although the maximum value of Y is 1.0, it does not follow that the ratio of Y to Y
is necessarily
< 1.0.
Consequently, the Licensee's cor-50 test relation is not necessarily conservative.
2.
VISCOUS FLOW For viscous, flow,, mass flow rate.
(m) is. proportional to the difference of the square of inlet pressure and. the square: of outlet pressure:.
mso
~
(64.7
-. 14.72) x const.
2 m
(14.7 P
- 2) x const.
test test.
mso 64 7
14 7
Lso Fso P
64" 7 x const.
Franklin'esearch
- Center, A0M@en d~e Frenk5n Insmu<eo
TER-C5257-53/54 mtest tes 2
Ltest Ftest x const P
14.7 test L50 Ltest 4 72 14 72 x
64.7 14.7 2
test Using in.
Hg units:
64.7
~ 131.73 14.7
~
29.92 P
"-12.92 test Lso 5.13 L'est 3 ~
CHOKED FLOW For choked flow, P
P Therefore, apart from orifice source'eynold's Number effects, mass flow rate - P source, abs'
~ volumetric flow rate (at source density) is independent of P
1 Therefore, since volumetric flow rate is proportional to the outlet'ercent of mass per unit time (denoted by L),
L50 P64.7 L
P test test 131.73 in.
Hg 29.92 in.
Hg
- 10. 2 CONCLUSION:
The above analysis; yields, the following, results, for the; correlation of 50 test FPL's ddP Method Viscous Flow Choked Flow 2.45 5.13
- 10. 2 Since the choked flow correlation is, the most conservative, this correlation should be used.
It should be; noted, that. FPL stated: in Reference 5 that the allowable local. leakage rate-at. Turkey: Point. isi 0;.,255 wt/day or 45, 000:. cc/min'..
At. the:
!ill. FranklimResearch'.Center, A OMske drThe Frsnl4rl Insd&te
TER-C5257-53/54 same
- time, PPL calculated airlock leakage rates (including instru~ent errors) which will cause an alarm to sound after an elapsed time of 1 minute as follows".
Lt
= 31.93 cc/min (personnel airlock) test L
=
7.98 cc/min (emergency airlock).
test It can be seen that even using the most conservative correlat'on (choked I
flow), the alarm will detect leakage which is a very small percentage of total allowable local leakage (less than 1%).
r 00 Franklin~Research. Center, h Dlvtsion othe FtenkSn Insets
-13'-.