ML20128K523
| ML20128K523 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 02/11/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20128K521 | List: |
| References | |
| NUDOCS 9302180197 | |
| Download: ML20128K523 (7) | |
Text
{{#Wiki_filter:- -_-_ -[porc v o UNITED STATES I,i NUCLEAR REGULATORY COMMISSION W ASHINGTON, D. C. 20555 %...../ EAfflLlyA_LEAT10!LJY THE OFFICE OF N.RQLEf6R REACTOR RE@tATION RELATED TO TE_JESJRVICE TESTING PROGRAM REllEF RE0QE.SJji IOWA Elf (IR.JC tlGHT AND POWER COMPANY DUANE ARN010 ENERGY CENTER DOCKET NUMBER 50-331 1.0 1![TJLOQQGl[QR The Code of Federal Regulations,10 CFR 50.55a(f), requires that inservice testing (IST) of certain ASME Code Class 1, 2, and 3 pumps and valves be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable addenda, except where relief has been requested by the licensee and granted by the Commission pursuant to 50.55a(f)(6)(i), or where the alternative has been authorized pursuant to 50.55a(a)(3)(i) or (a)(3)(ii). In requesting relief, the licensee must demonstrate that: (1) the proposed alternatives pravide an acceptable level of quality and safety; (2) compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety, or (3) conformance with certain require-ments of the applicable Code Edition and addenda is impractical for its facility. Section 50.55a(f)(4)(iv) provides that inservice tests of pumps and valves may meet the requirements set forth in subsequent editions and addenda that are incorporated by reference in 50.55a(b), subjact to the limitations and modifications listed, and subject to Commission approval. NRC guidance contained in Generic letter (GL) 89-04, Guidance on Deve70 ping Acceptable Inservice Testing Programs, provided alternatives to the Code requirements determined to be acceptable to the staff and authorized the use of the alternatives in Fositions 1, 2, 6, 7, 9, and 10 provided the licensee follow the guidance delineated in the applicable position. When an alternative is proposed which is in accordance with GL 89-04 guidance and is documented in the IST program, no further evaluation is required; however, implementation of the alternative is subject to NRC inspection. These regulations authorize the Commission to grant relief from or approve alternatives for ASME Code requirements upon making the necessary findings. The NRC staff's findings with respect to granting or not granting the relief requested or authorizing the proposed alternative as part of the licensee's IST Program are contained in this safety Evaluation (SE). The licensee submitted Revision 9 of the Duane Arnold IST program in a letter dated January 5, 1990. The licensee's program is based on the requir.ements of Section XI of the ASME Code, 1980 Edition, with addenda through Winter 1981. An SE was transmitted to the licensee in a letter dated March 11, 1992, which contained a Technical Evaluation Report (TER) prepareo by EG&G, Idaho. The March 11, 1992, SE addressed the second 10-year interval from February 1,1985 to february 1, 1995. The TER contained 15 action items which the licensee was requested to address. The licensee revised helief Request VR-013 and sub-i mitted responses to Item numbers 9,10, and 11 in a letter dated June 16, 1992. In addition, the licensee also revised relief request VR-017 in 9302180197 930211 DR ADOCK 050 1
, - -.... response to Item 5 in a letter dated June 30, 1992 The licensee's acons to address item 5 for Relief Request VR-017 and Items 9,10, and 11 for lef Request VR-013 are evaluated in this SE. 2.0 IERXL10N ITEMS 2.1 Jigm Number 5 in Relief Request VR-017, relief was granted from the requirements of IWV-3415 to fail-safe test valves by observing operation of the valves upon loss of actuator power. The licensee identified three sets of valves which have fail-safe actuators and are fail-safe tested by means other tha, normal valve stroking For normal stroking, solenoid valves control the air supply to these actuators. De-energizing the solenoid valves has the same effect as interruption of the electric power or air supply, which is the requirement of IWV-3415. The licensee's previous submittal did not describe the test method and frequency in sufficient detail for the NRC staff to make a determination that the valves fail-safe tested in a manner other than normal stroking would simulate a fail-safe test. Therefore, the relief was denied for the main steam isolation valves (MSIVs), control rod drive (CRD) valves, and service water valves, as these valves were indicated as fail-safe tested by means other than normal stroking. Relief previously was granted fr valves for which normal exercising has the same effect as the loss of actuator power as required by IWV-3415 (reference NRC SE dated March 11, 1992). The licensee stated that service water valves CV-4909, CV-4914, and CV-4915 are now tested on a quarterly frequency in compliance with the Code requirements. 2.1.1 Ljcensee's Angmalv Response The licensee reviewed the testing methods for these MSIVs and CRD valves and revised Relief Request VR-017. This relief request is evaluated below. 2.1.2 Relief Reauest VR-017: The licensee has requested relief from the fail-safe testing requirements of Section XI, Paragraph IWV-3415, for all solenoid and air operated valves in the licensee's IST program equipped to fail open or closed. The licensee is proposing to normal stroke the valves to their fail-safe position. When the valve cannot be tested in this manner, a separate fail-safe test will be conducted. Licensee's Ba_sijs for_Pequestina Relief: The licensee states: 'So'lenoid valves s which control the air supply to air-operated valves and direct solenoid-operated valves must stroke to their fail-safe position upon interruption of their electric power or air supply, ] "De-energizing the solenoid valve has the same effect as loss of electrical power or loss of control air. Therefore, stroking the valve from the control room (BT0, BTC) to its fail-safe position constitutes a fail-safe test for uost valves."
/ ,/ j-' y/ Altgrqatq T str king (_BT e o the clo siJt r sd O ng: e o,tiBTC) to thThe lic se c v lv ns a 3. Wher s is tute e ense co af e fail e pr s e necess pr oiv dedmpl opo ic ted ary.ull s fe te tedm thods ,r s a e: e epar te failfail s fe str ke te t s a "fo o po i a s tion mo t s s a r e a s t!S111:to their f u s (F ).of sd e a ST c onfigur tio v lv to c a o figur No n s s fe te t, atio additio es CV-4412 ail s fee ify tr a r a equipped ns a u s ns po is tioe fail s fe to,failrta l no util nl izing thee ist, o a CV-4416 x te ting of a The a s CV-4420 CV-4413 n by m r open se ope whe sup ly.v lv eans a CV-4 r tio. proper e te t a r p e closur Thiss hav CV-44 418 CV-4 gilttt tha n s T snle s le he follo in v lv si e e tw 21 CV-4 415 o a noids m de niu ds o fail s fen be te ted n e. gn l o fr s n a 419 or om This fail de ca ad are ml w n a an str king.lv/o en gv r a o tage/shutdergiz u a The s the m de. o s o es e s fe s a sec are this o s len lin The f \\ od m de is te t n o own. ke e thefail s fe o cas which ir t e by nor noid s s ml is lo \\ up ly systeeps the a s v lv p a nitr ed a ss ogen beingm de is ni o on es tr whichclo of oge a v lv sur r o qe a epo istio n m. ele tric l arterly basio tr l e n lo e pr The c c n of which essur r teopen, is ss the MSIVs sup lied v lv clo n (intere ha o a p of a the a nitroge\\ nl s de of se s e full s the exhau tedto the ad actu to The a c clo n v lv sprinayed ur s n supply to th during sta s a 20: clo e u de r a e 10 he will to n s air-CV-18 e is pe for% g fo, rtide atm ha pointbe in 3ospher of e rtup The r is 49 md perfor at to 5 upo the se CR9 a tu tora tu tor, s e c during the e overcom v lv CV-1850 c a md wh eve e ich s n ap r a a ry r fu l econ a e the the air ds, failur m p opriate " SCRAM In e ing o tago thly a d es n e 18 pisto, ar 49 pneu e te ted af e a te tm tic forv lv ter the a a of ad n with n n s le in s the o CV-1850 u s es ni ertio one to their fai which to fallo ds SV-1855ntim s c ).will e. of . fstbl_at e eah c s l clo A e te t" ev s fe the CRD te t ign: se a s v lv open " nd alloper tio he Code el. T SV-1 s the a a \\o a T r isted (aboNote:856 ery r fu lpo it s tu tor n e io v lv of a ar a n 'l s forthe ergiz de ing o tagea full r e e v lvequir on ief pow ther en ve a e er in the Mwhich upo r u e s that on equ or es ar e mtio e e 89 S et a ah ml n lo fail s fe hydr hydrwhich. The CRAM s c 'is ad no n for HSIVs n r cus a licwill sign l ha ar h a ss a alu ic c sd e u a s in luded11, 19 exer of belo. o tr ! ontr lallow CV-9.cising haactuatorv lv c c a n c 1R1h0i9L11511 ad w n 2 e s be te ted CRD o o SE v lvsupplem. u it.) u in ts e talThe ls the pow n er. s a IV e. n sameeffe tReliefby obs s 1: ic fails to th The te t ense v lv s er ing a r lief c was m thode has v e e es as lo s gr s theup ly to thwhich clo e re fo a ted p n es frs bmit of ed r tn and ss u e s c o tr l po is tio e tw equ ted n o e s le o s ts cy the n o en nio dsu der i then e s de on a tu to :ai ) a l c a (i of ad of n v lv a the clo r es se a tu torr v iv c oss s the MSIV a a of pistoes; o ele his te. r (2) ctric l T n a 1 a lo s stin(g )is upply to A ss clo of sur c e o du tedsign l n c a at
'f / / ' 1 611ernate Testina: The licensee proposes: "For most configurations, normal stroking (BT0, BTC) to the fail-safe position of valves equipped to fail open i or closed constitutes a full stroke test (FST). No additional testing of these valves is necessary. .j Where complicated fail-safe configurations exist, or where test solenoids are provided, a separate fail-safe test, utilizing the proper solenoids and/or l methods are used to verify true fail-safe operation. The following valves are tested to their fail-safe position by means other than normal stroking. Wilyl: CV-4412 CV-4413 CV-4415 l CV-4416 CV-4418 CV-4419 CV-4420 CV-4421 These valves have two fail-safe modes. The first is loss of electrical supply. This mode can be tested on line by normal closure of the MSIVs. The closure signal deenergizes the solenoid valves which control the actuator air-l valves. This fail-safe mode is tested on a quarterly basis and.during startup from an outage / shutdown. The second fail-safe mode is on loss of nitrogen supply to the actuator. In-this case the nitrogen being supplied to the underside of the actuator piston, which keeps the valve open, is exhausted to atmosphere upon a failure of the' supply system. The rate of closure will be in 3 to 5 seconds,.after the nitrogen pressure has decayed to the point at which the air-valves will reposition (internal spring force has overcome the pneumatic force). A test which closes the valve 10% is performed monthly and a test which closes the' valve full close is performed every refueling outage. GD: CV-1849 CV-1850 These CRG valves are tested to their fail-safe position on a full SCRAM signal during the " SCRAM insertion time test" every refueling outage. The appropriate solenoids SV-1855 and SV-1856 are ' energized which will allow CV-1849 and CV-1850 to fall open." (Note: there are 89 hydraulic control units - with one of each CRD valve listed above on each hydraulic control unit.)- Luluation: The Code requires that fail-safe valves be tested by observing the operation of the valves upon loss of actuator power, Relief was granted for all valves.for which normal exercising has the same effect as loss of actuator power in the March 11, 1992, SE. The licensee has resubmitted the relief request and has included supplemental test method and frequency information for MSIVs and CRD valves. The relief for these two sets of valves is discussed below. Test Method of MSIVs: Each MSIV_ fails to the closed position on: (1) a loss of electrical supply to solenoid valves which control' the actuator air-valves; or (2) a loss of -nitrogen supply to the underside of the actuator piston. (1) A closure signal deenergizes the solenoids and closes the MSIV. This testing is conducted at-
the Code-specified frequency of once every 3 months and also during startup-- from a plant shutdown.. (2) Venting the nitrogen under the piston will allow the spring force to overcome the pneumatic force in the valve actuator and close the valves. A test which closes the MSIVs 10% to test this fail-safe mode is conducted monthly and a full closure test is conducted each refueling outage. The licensee's testing provides an acceptable level of safety because the proposed testing eliminates the motive forces that hold an MSlV open and - causes the valve to actuate to its fail-safe position if the valve is operating properly. However, the licensee should ensure that the testing-incorporates the recommendations of General Electric Service Information Letter 477 and NRC Information Notice 85-84, " Inadequate Inservice Testing or Main Steam Isolation Valves." The proposed alternative to the Code test method requirements is authorized pursuant to 50.55a(a)(3)(1) provided the licensee incorporates the recommendations of General Electric Service Information Letter 477 and NRC Information Notice 85-84 within 6 months from the date of this SE. Test Method of CRD Valves: CRD system valves CV-1849 and CV-1850 are the scram inlet _ and outlet valves, respectively. These valves are air-operated and fail open on a loss of instrument air. Reactor protection system (RPS) channels energize solenoid valves SV-1855 and SV-1856 open which results in air being vented from the header supplying air to the scram valve::.- This action rapidly inserts the associated control rod. During refueling outages, these valves are _ tested to their fail-safe position on a full scram signal during the " SCRAM insertion time test." This testing is conducted for each control rod. The licensee's testing provides an acceptable _ level of safety because the valves are tested-to their fail-safe position when the valves actuate on the RPS scram signal to both solenoid valves, which simulates a loss of instrument air. The proposed alternative to the Code test method requirements is authorized pursuant to 50.55a(a)(3)(i) based on the alternative providing an acceptable level of quality and safety, i Test Freouency of MSIVs and CR0 Valves: The licensee's proposed testing frequencies for the MSIVs and'CRD valves-described-in this relief request are consistent with the exercising test' frequency requirement! as listed in ASME/ ANSI OMa-1988, Part 10 (OM-10), " Inservice Testing of Valves in Light-Water Reactor Power Plants," Section 4.2.1.l. In final rulemaking effective September 8,1992, published in the Federal Reaister, Volume 57, No. 152, Thursday,-August 6, 1992, the staff approved the 1989 Edition of ASME Section XI which references OM-10 as alternative rules for IST of valves.
~ 9. ,.: Section 50.55a(f)(4)(iv) states that inservice _ tests of valves may meet the requirements set forth in subsequent editions and addenda that are incor-porated by reference in 50.55a(b), subject to the limitations and modifi-cations listed, and subject to Commission approval. Section 50.55a(f)(4)(iv) further states that portions of editions or addenda may be used provided that all related requirements of the respective editions or addenda ~are met, The: licensee is authorized to use the alternative OH-10 rules pursuant to 50.55a(f)(4)(iv), and relief is no longer required. Whether all-related requirements are met is subject to NRC inspection. 2.2 Item Number 2 in relief request VR-013, the licensee requested relief from the valve exer-cising frequency, stroke time-measurement, and corrective action requirements of Section XI, Paragraphs IWV-3411, IWV-3413, and IWV-3417, respectively, for the solenoid valves associated with the scram discharge volume vent and drain-valves (SV-1868A, SV-18688, SV-1869A, and SV-18698). This relief request was preapproved by GL 89-04. The licensee proposed testing these solenoid valves with the associated scram discharge volume vent and drain valves during the- " mode switch placed in shutdown test" which is performed _each refueling outage. The testing method was acceptat'le; however, the licensee was requested to provide technical justification for not performing this_ testing during cold shutdowns. 2.2.1 Licensee's Anomaly Response The licensee revised the relief request to include the solenoid valve's associated with the scram discharge volume vent and drain _ valves. Solenoid valves SV-1868A, SV-1868B, SV-1869A, and.SV-1869B activate CV-1859A, CV-1859B, CV-1867A, and CV-1867B; however, these control valves may also be_ tested quarterly by use of alternate solenoid valvts which are not. tied to the reactor protection system. Testing the solenoid valves associated with the SCRAM discharge volume vent and drain valves would require or result in an initiation of a full SCRAM _ signal. Due to the extensive effort and opera-tional constraints associated with scram testing, this-is impractical'to accomplish on a quarterly basis or even during cold-shutdowns. 2.2.2 Additional Information Provided by Licensee The licensee provided additional justification for not testing these solenoid valves in-a phone conversation with the staff on November 23,.1992. The licensee stated that the function of the' solenoid valves ' associated with the scram discharge _ volume vent and drain valves.is similar to that of the scram valves on_ the hydraulic control-units. The only method available to cycle these valves is by generating a scram signal. Although a scram signal can be inserted during cold shutdowns, this would cause a high-pressure differential across the CRD mechanism seals which could lead to premature seal degradation. i s.. - -
e. 2.2.3 Evaluation of Licensee's Anomaly Response The additional information provided by the licensee adequately justifies testing these valves on a refueling outage frequency. Therefore, the concern of the anomaly has been addressed and no further NRC action is required. 2.3 Item Neber 10 In Relief Request VR-013, the licensee requested relief from the valve exer-cising frequency, stroke time measurement, and corrective action requirements of Section XI, Paragraphs IWV-3411, IWV-3413, and IWV-3417, respectively, for the following CRD hvdraulic system air and solenoid operated valves: backup scram valves, scram inlet valve from the char.ging water header, scram outlet valve to the scram discharge header, and instrument air vent valves for CV-1859 and CV-1860. This relief request was preapproved by GL 89-04. The licensee's proposed testing for all these valves, with the exception of the backup scram valves, is in accordance with GL 89-04, Position 7, and would, therefore, provide an acceptable level of quality and safety. However, since the backup scram valves, SV-1840A and SV-1840B, provide a redundant protective function, degradation of these valves may not be evidenced by rod insertion times. Verifying only that these solenoid valves energize to vent the scram valve pilot air header also provides no measure of valve degradation. Since these are rapid acting solenoid valves, it was recommended that the licensee consider stroke timing these valves as outlined in GL 89-04, Position 6. 2.3.1 Licensee's Anomaly Response The licensee stated that stroke timing these backup scram valves, which are rapid acting solenoid valves, is extremely burdensome and would cause routine surveillances to become lengthy. The licensee, in order to eliminate the need to monitor the valve stroke times for purposes of degradation, is placing these valves in their preventative maintenance program and inspecting and refurbishing or replacing the valves every other refueling outage. 2.3.2 Evaluation cf Licensee's Anomaly Response The licensee's proposed plan to inspect and refurbish or replace the backup scram valves every other refueling outage does provide a means of preventing the solenoid valves from degrading to a condition where they cannot perform their safety function. This action satisfies the concerns of the anomaly. As a part of their maintenance program, the licensee should keep records of the condition of the valves ar.d the repairs or replacements needed so as to determine if the inspection frequency proposed is adequate, in addition, the licensee is requested to refer to a paper in the Proceedings of the Second NRC/ASME Symposium on Pump and Valve Testing entitled " Inservice Diagnostics for Solenoid Operated Valves," which contains information on inspection. surveillance, monitoring, and maintenance of solenoid operated valves. If the licensee determines another method is available, this relief request should be revised. The licensee should perform this review within one year from the date of this SE.
t
- 2.4 Item fiumber 11 In Relief Request VR-013, the licensee proposed exercising the backup scram check valve, V-17-0062, each refueling outage by verifying that the backup scram valves vent air when energized.
This check valve can be verified to stroke open by ensuring that both backup scram valves vent air when energized. However, as outlined in GL 89-04, Position 1, verifying only that both backup scram valves vent air is not sufficient to demonstrate a full-stroke of this check valve. The licensee was advised to investigate and implement a method of verifying the full-stroke capability of this check valve. 2.4.1 Licensee's AnomAAsJonse The licensee confirmed that nonintrusive testing may be ut.ed to prove the This method valve fully opens during performance of surveillance testing. The will prov de assurance that the valve acceptance criteria is being met. use of non1:trusive testing has been added to the alternative testing section of Relief Regt.est VR-013 and will be implemented by the next refueling outage. 2.4.2 Evaluatic, of Licensee's Anomalv Response By incorporating nonintrusive test methods to verify that the backup scram check valve fully opens when the backup scram solenoid valves vent air when The energized, the licensee has satisfied the concerns of the anomaly. frequency has already been "preapproved" by GL 89-04 (reference previous SE). No further f1RC action is required for the current IST interval. Principal Contributor: J. Colaccino Date: February 11. 1993 i
== : x~~ -= m ~ em m =m - mua===-~ =n. L}}