ML20237L297
| ML20237L297 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 09/01/1987 |
| From: | Jocelyn Craig Office of Nuclear Reactor Regulation |
| To: | Nerses V Office of Nuclear Reactor Regulation |
| References | |
| TAC-65608, NUDOCS 8709080336 | |
| Download: ML20237L297 (13) | |
Text
_
., l
.j p no o,, UNITED STATES f
. [y g NUCLEAR REGUL ATORY COMMISSION 1 E W ASHINGTON, D. C. 20555 .l 49 ..... '
September 1,1987 <
l Docket No. 50-271 MEMORANDUM FOR: Victor Nerses, Acting Director Project-Directorate - I-3 Division of Reactor Projects I/II FROM: John W. Craig, Chief Plant Systems Branch Division of Engineering and Systems Technology ;
SUBJECT:
VERMONT YANKEE.- RESPONSE TO NECNP'S THIRD SET OF INTERROGATORIES RELATED TO THE SPENT FUEL P0OL EXPANSION TAC N0. 65608 Enclosed (Enclosure 1) is our response to the Vermont Yankee spent fuel pool expansion hearing third set of interrogatories for NECNP for which the Plant Systems Branch has the primary responsibility. Specifically, Questio.ns numbered 3 through 20 are addressed. There are several questions which deal, in part, F.. with the desire to receive copies of documents in the possession of the staff. A set of these documents which have not been previously provided is also enclosed (Enclosure 2). n
\
cs- k
/JohnW.Craig, Chief Plant Systems Branch Division of Engineering and Systems Technology
Enclosures:
As Stated cc w/ enclosures:
V. Rooyey PDR (
CONTACT: J. Ridgely X24742 p(g10W~ . - -
p
-3.
,..-' s "},/ ,.
PLANT SYSTEMS BRANCH'S RESPCNSE 70 l NECNP'S THIRD SET OF INTERROGATORIES YERMONT YANKEE I I
DOCKET NO. 50-271 3
hegogatoryNo.3 l The staff states in the NRC Staff's Prief in Opposition to the Brief of Applicant June 25, ~1987 (hereinafter Staff Brfef) at page 5 that the current YY tech specs "do not ensure redundancy in the spent fuel pool cooling system."
Please explain what elements of redunda7cy are af ssing from the current tech specs.
Response.
The Technical Specifications are not intended to ensure redundance in the spent fuel pool cooling system. Rather, in accordance with the Commission d' Policy Statement on Technical Specifications for Nuclear Power Reactors dated February 6,1987 (52 FR 3788), "[t]he purpose of Technical Specifications is to impose those conditions or 11mitai.19ns upon reactor operation necessary to obyfate t% possibility of a abnormal situation or event giving rise to an immediate threat to the public health and safety by establishing those conditions of operat1on whfch canrot be changed without prior Commiss1on approval and by identifying those features which are of controlling importance to safety."
Refer to the respor'e to Interrogatories numbered 4 and 5.
Interrogatory No.-4: !
The proposed new tech spec submitted by VY and attached as Appendix B to the
- Staff Brief, states as its objective: "[t]o assure that adequate cooling is available for heat removal in the spent fuel pool." Would compliance with the preposed tech spec ensure the appropriate redundancy for the cor_e decay heat removal system? Please explain your answer.
Response
Steff review of the ifcensee's Technical Specification change request is to assure that if the request is granted, there will be no degradation in the plant's abfif ty to mitigate the consequences of a design basis accident assuming a concurrent single active failure as described in the Vermont Yankee FSAR. The proposed Technical Specification provides assurance that no degradation in the plant's ability to mitigate the consequences of any design basis accident and single active failure will occur. Thus, we conclude that compliance with an acceptable Technical Specification will ensure the appropriate redundancy for the core decay heat removal systems.
Interrogatory No. 5:
Is it the staff's view that compliance with the proposed new tech spec would ensure that the spent fuel pool cooling system meets the single failure criterion? Please explain your answer.
Response
No. The proposed Technical Specification is to provide assurance that the RHR systems are available to serve the reactor when called upon.
L _ __ -__ - .
Interrogatory No. 6:
Is it the staff's view that ' compliance with the proposed new toch spec would ensure that the core decay heat removal system meets the single failure criterion? Please explain your answer.
Response
Yes. The Technical Specification would prohibit the licensee from removing a loop of the PHR system from being able to serve the reactor unless the reactor is in either cold shutdown or refueling conditions.
Interrogatory No. 7:
What requirements and/or criteria apply to the determination of whether sufficient " redundancy" exists in the spent fuel pool cooling system?
Response
Staff criteria states that the spent fuel pool cooling system should have a sufficient number of trains such that with the loss of any one train, due to a single active failure, the remaining train (s) can remove 100% of the normal maximum decay heat load as defined in Standard Review Plan Section 9.1.3 and in Branch Technical Position ASB 9-2. This capabfifty then satisfies the requirements of General Design Criterion 44, " Cooling Water." However, General Design Criterion 44 does not explicitly identify that those systems which are labeled as " Spent Fuel Pool Cooling Systems" are the only systems which can be considered as "a system to transfer heat from structures...important to sa fety. " Thus, in the broader scnse those systems which can remove the spent fuel decay heat are (1) the two trains of the spent fuel pool cooling system and (2) loop A of the Residual Heat Removal System. It is these systems which can remove 100% of the nonnal maximum decay heat loed as defined in the Standard Review Plan and thereby satisfy the requirements of General Design Criterion 44.
Interrogatory No. 8:
In view of the fact that both the proposed new tech spec and tFe affidavit of John N. Ridgely (Appendices B and C to the Staff Brief) use 150 F as the applicable temperature limit, has the Staff made the judgment that 150*F is the appropriate limit for purposes of this recoested amendment? If so, plea o explain why a limit other than that contained in the Standard Review Pier applies in this case.
Fesponse:
Yes. The staff believes that t.he licensee can provide adequate justification for a maximum pool water temperature of 150 F. The licensee has provided the results of their evaluation of the spent fuel pool cooling and cleanup system which indicates that the cooling system can operate with a pool water tempe-ature of 150*F without degradation. Some degradation in the cleanup I system could occur above the 140"F specified in the Standard Review Plan. j However, the licensee has comitted to isolate the cleanup system when )
l l {
l )
I
the pool water temperature is equal to or higher than 140*F. The staff is aware that there are no spent fuel pool water temperature alarms in the control room, and therefore, continues to have questions concerning the centrois to be implemented by the licensee to ensura that the above commitment is met. This remains an open 1ssee with the staff at this time.
Interrogatory No. 9:
Has the staff applied the 140"F limit contained in the Standard Review Plan to other ceracking applications? Please explain why or why rot and identify other reracking amendments as to which a 140*F_ limit has been applied.
Response
All utilities applying for an operating license or a Ifcense amendment to modify the storage capability of the spent fuel pool are reviewed against the guidelines of the. Standard Review Plan. The applicant / licensee cust either meet the 140'F limit or provide adequate justification fer 6 different temperature limit. Historically, the maximum approved temperature limit that we are aware of for the maximum nonaal heat load condition is 150 F.
A brief review of the technical input to safety evaluation reports on hand which relate to spent fuel pool storage capacities indicates that the following plants were reviewed in accordance wf th a spent fuel pool water temperature limit of 140"F and 150"F, as noted below. This review encompassed reports from December 1981 to the present.
J40FWaterLimit 150*F Water Limit Grand Gulf 1 '
Ginna Turkey Point 3 & 4 Big Rock Point Oyster Creek Brunswick 1 & 2 Sumer Yankee Rowe McGuire 1 & 2 Quad Cities 1 & 2 North Anna 1 & 2 H. B. Pobinson 2 Rancho Seco r Trojan Nine Mile 1 ,
Oconee 2 ANO 1 8 2 Farley 1 & 2 San Onofre 1 .
Dresden 2 Haddam Neck Interrogatory No. 10:
The staff states at page 11 of the Staff Brief:
"The [1977] Staff SER did not make clear that the licensee was permitted to use one train of RHR to provide supplemental trent fuel pool cooling in cases of nonnal refueling (1/3 core offloads) if needed to maintain spent fuel pool temperature below 150*F."
i.
l -
l* 4 a) Was the Staff aware prior to the Prehearing Conference of April 21, 1987, that VY is, under its current license, required to use one train of RHR to !
l cool the spent fuel pool in cases of. normal refueling (1/3 core offload) in order to keep the pool temperature below 150 F?
Response to 10a:
No, the current license.does not require the use of the RHR system.
Interrogatory No. 10b:
Did the Staff intend in the 1977 spent fuel pool amendment to permit VY to use one train of RHR to cool the spent fuel pool in cases of normal refueling?'
Response to 10b:
The staff can not identify the specific intent at the time of the approval of the 1977 spent fuel pool amendment. The intent of the current licensing review is to ensure that the heat removal systems are single failure proof.
Interrogatory No. 11:
With reference to the proposed new tech spec (Staff Brief, Appendix B),
piease answer the followino:
a) Should line 3 of Specification 8 of 9 3.14 be corrected to read ,
". . . ,f ncapable of maintaining. . . ?"
Response to 110:
No. The proposed Technical Specification was proposed by the licensee and it has not been found acceptable by the staff, i Interrogatory P.'o. lib:
Does Specification C of 6 3.14 require the reactor to be shut down immediately whenever both fuel pool cooling subsysters are made or found inoperable?
Please explain.
Response to lib:
No. The Technical Specification proposed by the 11censee only requires that the reactor be in a cold shutdown condition prior to the spent fuel pool water l temperature exceeding 200*F. If the spent fuel pool water temperature was above 150'F, but below 200*F, and both spent fuel pool cooling trains were inoperable, the licensee would be in conformance with the proposed Technical Specification. This is not acceptable to the staff. )
,_-} }
Inte rrogatory- No. 11c:.
- Does Specification C of 9 3.14 require- the reactor.to be shut ~down immediately whenever the fuel pool . temperature cannot be maintained below IS0*F with use of the spent fuel pool cooling systems alone? In the alternative, does this specification permit' the. plant to operate 1f the pool temperature can be raintained below 150*F by using RHR7 Response'to lic:
Fo. .The Technical Specification in Appendix B is a proposed Technical Specification from the licensee and has not been found acceptable by the . 4 staff at this time. As proposed, it is not clear. However, the staff will
. require that the plant not be permitted to be in any operating condition other than cold shutdown or refueling when any portion of the RHR system is aligned to cool the spent fuel pool.
Interrogatory No. Ild:
Does the reference to 200*F in specificLtien C of 9 3.14 mean that even if both fuel pool cooling subsystems are made or found inoperable, plant operation can continue unless and until the fuel pool temperature exceeds 200 F7.. If not, please explain the significance of 200*F in the context of the specification.
Response'to 11d:
Yes. Refer to the response to Interrogatory Number 11a and lib. The significance of:200*F is thet it is less than the bofling point of water (212*F) and thus there would be no potentially significant release .of radioactive materials to the atmosphere due to steaming of the pool water.
Interrogatory No. 11e:
Specification A.2 of 9 4.14 requires the monitorino of fuel pool temperature and level. Please explain whether this proposed tech spec or any other current or proposed section of the VY license requires VY to take specific actions when specific pool temperature or level limits-are exceeded. If so, please identify. If not, please explain the purpose of the monitoring requirement.
l.
f l
Response to lle:
The proposed Technical Specification would require the ifcensee to monitor the fuel pool water temperature, however, the Itcensee has not proposed any action to be taken when the pool water temperature reaches 150 F,. The licensee has committed to modify the plant operating procedures to require isolation of the spent fuel pool cleanup system when the pool water reaches 140*F. Thus, instrumentation is needed for the operators to monitor the pool water temperattfre for two separate actions to be taken at two different pool water temperatures. There currently are two existing plant Technical Specifications related to the spent fuel pool water. Technical Specification 3.12(C) speciffes maintaining the pool water level at 36 feet with a surveillance requirement to record the water level daily. Technical Specification 3.12(H).
identifies the maximum pool water temperature of 150*F with a surveillance requirement to record the water temperature daily. In addition, when the water temperature exceeds 150'F, the licensee is to immediately stop all fuel handling activities which could increase the water temperature and implement measures to reduce the pool water temperature. There is no other proposed section of the VY license which would require specific action to be taken l
based on spent fuel pool water temperature or level, to the best of our l' knowledge.
l l Interrogatory No. 12:
What effect dces the change from an annual to an 18-month refueling cycle have on the combined heat load of the spent fuel pool and the core? Please provide all aralyses, calculations er other documents which support your response.
t
Response
!!hile no specific analysis has been perfonned to determine the effect of the I change in the heat generation rate associated with 2870 fuel bundles with an annual refueling cycle versus an 18-month cycle the effect can be seen from a recent analysis. This recent analysis indicates that the 18-month cycle fuel will generate approximately .315% more heat per fuel bundle than the l 12-month cycle fuel. The calculations are included in Enclosure 2. The heat generation rate for the orfpinal plant licensing basis (f.e., the storage capacity of 600 fuel bundles from annual refueling cycles) is approximately 5.75 MBtu/Hr and would result in a calculated pool water temperature of 149.3*F. The heat generation rate from one third of a core (132 fuel bundles) from an 18 month fuel cycle is approximately 6.46 MBtu/Hr and would result in a calculated pool water temperature of 157.3 F. Thus, a third of a core from an 18 month fuel cycle gens. rates more heat than 600 fuel bundles from annual l fuel cycles. (Note that these calculations used the guidelines of Standard Review Plan Section 9.1.3 and Branch Technical Position ASB 9-2 and included the single failure of one spent fuel pool cooling system trafn).
1
V l7 . $ q g
.4 .
L
/
Interrogatory No.13:-
The~ current fuel pool limit.of 2000 assemblies is based on-certain assumptions
- - regarding the heat' load.which must be removed and the heat removal capabilities ~
of the cooling. system. What effect does the change to an 18-month refueling
- cycle have on the heat load which must be removed from each' assembly?
Response
On a."pe fuel bundle" basis, the change to an 18-month refueling cycle will.
fincrease the heat generation rate by approximately 0.315%. Refer to the.
response to Interrogatory Number 12.
Interrogatory No. 14:
'In the letter of June 11, 1987, from Warren P. Murphy, Vice President an'd-Manager-of Operations, VY, to V. L. Rooney, NRC, (FVY 87-65) Mr.-' Murphy. refers in the first sentence to "recent discussions with NRC staff concerning certain issues associated with'. .' this proposed amendment. (This letter is cited at.
note 7 on page 5 of. the Staff Brief). Please describe the substance of these discussions with VY in which the issues covered in thel June 11, 1987 letter were discussed.
' Response:
The substance of these discussions is documented in rotes of the various
- telephone conference' calls which are in the Public Document Room and copies of which were previously provided as part of our response to the original set of interrogatories.
Interrogatory No.15:
Identify all persons involved in the discussions referred to above.
Response
l The conference call notes, discussed in the response to Interrogatory No.14, Ifsts all persons involved in the discussions.
Interrogatory No. 16: ;
Who. initiated these discussions and in what manner? Did the staff send
.any questions to VY on these issues? If so, provide them.
Response
The^ conference call notes discussed in response to Interrogatory No.14 identifies who initiated the cell and the purpose of the call. The staff L
has prepared a reouest for additional information which is available in the Public Document Room.
Interrogatory No. 17:
Provide any documentation of these discussions, including but not limited to notes and/or minutes.
J
.4 ,
- s. .: y
Response
~
'The' requested documentation is either in the' Public Document Room or was "provided in ' response to' NECNP's first set of-interrogator f es.
Interrogatory No. 18: 1 W refers at page 3 of Mr. Murphy's letter to an evaluation which concluded that each of..the. components of the spent fuel pool cooling ' subsystems are capable'of operation at a fluid temperature of 200'F. Has this evaluation or.
any other documentation related'to this issue been given to the staff? If so, please: identify and provide..
Response
' No.' However, a discussion of the design temperatures for the spent fuel pool cooling and cleanup' system was provided by the licensee as enclosure I to a submittal _ dated April 9,1987. This sobmittal is in the Public Document Room.
. Interrogatory No. 19:
Is it the staff's. view that each of the components of the spent fuel pool cooling subsystems-are qualified for operation at a fluid tem 3erature of 200*F? Provide all analyses, calculations, evaluations or other documents which-relate to the ability of these corponents to operate at a fluid
. temperature of 200'F.
- Response:
-The staff accepts the licensee's statement as betr>g correct. Further, it is reasonable that the spent fuel pool cooling system can handle fluid at 200'F and it is consistent with the capabilities of similer systems at other facilities.
Interrogatory No. 20:
Does the staff acree that "there is no need to augment spent fuel pool I cooling" with RHR?' (See Licensee's. Responses- to NECNP's First Set of
. Interrogatories, July 1,1987, Interrogatory No. 23, p. 20). Please explain your' answer and provide (or reference, if previously provided) the analyses, calculations or assessments which support your view.
Response
L No. The licensee stated in response to question 17 in the submittal dated November 24, 1986, that "the spent fuel pool cooling system is not relied on'until sufficient decay [of the spent fuel heat load] har taken place to remove RHR from augmented fuel pool cooling service." .In a conference call (documentation cf which was provided as part of our response to the first set of interrogatories), the licensee stated that 'they have always used one loop of RHR in the spent fuel pool cooling mode of operation during refueling.
' Based on the licensee's statements, we conclude that there is a need to attgerent. spent fuel pool cooline.
. g
- es
_ Enclosure 2
l : .' , .
i.c;1 Vermont 1 Yan kee < # Bundles'= SFP Capec'ity (Normal Haat Load Calculation) h ..
I
- l. ; Batch' .;No Bun Decay Heat- -Cumm Heat- Cumm #. Bun Ts 1 132- 6.46233 6.46233 132' .02 i 34 .
EAbsumptions:
PownripernBundle ='.15.44197 MBTU/Hr
' Irradiation Time =- 39420. Hours R2 actor Power =' 1665. MWth Raference: N REG-0800, Standard Review Plan (1) Section 9.1.3 Spent, Fuel Pool Cooling and Clean-up Systems,'-Rev. 2
'(2). Branch-Technical-Position ASB 9-2 Residual' Decay Energy for Light-Water Reactors
'for Long Term Cooling, Rev. 2 Spent Fuel Pool Cooling System Service' Water System.
Outlet Temperatures (F)- '128.57 121.93 '
-Inlet' Temperatures (F) 157.29 (Poo1~ Temp) 85.00 Water Flow Rates (M1b/Hr)' .225 .175 Haat Exchanger Surface Area (SqFt) 500.0 HDat Exchanger Overall Conductance 375.0 BTU /SqFt-He-F The two pass correction factor, F= .873
>t r'
m- .
I,*.
1 '
- t r(.
M 2, . '
L.. .Ver rrs.ilt Y, Ankee 1/4. Core'=;SFP. Capacity. (Normal L Heat Load ' Calculation)- j L-
- c Datch. No Bun Decay Heat' . Cumm Heat. Cumm 8 Bun Ts-a 1~ 9:2 - 4.48991- 4.48991 92 .02
'2 9:2, .45495 4.94485 '184 1.02.
~3' 92 .25006 5.19491 276- 2.02 q 14 921 .18374 5.37865 368 3.02 1 15 92? .15625 .5.53490. 460 4.02 !
6 92= .14348' 5.67838 552- 5.02L
'7 48. e '07123
. 5.74960 600 6.02 L Assumptions:
Power perfBundle =' 15.44197'MBTU/Hr
- Irradiation Time =- 35040.' Hours Reactor Power = ' 1665. MWth References NUREG-0800, Standard' Review Plan (1) Section 9.1.3 Spent Fuel Fool- Cooling and Clean-up Systems, Rev. 2-(2) Branch' Technical Position ASB 9-2 Residual Decay Energy for Light-Water Reactors for'Long Torm Cooling, Rev. 2 t
Spent Fuel Pool Cooling' System Service Water Svstem o
Outlet Temperatur es (F) 123.77 117.85 g Inlet Temperatures'(F) 149.32 (Pool Temp) 85.00 i
Water Flow. Rates (M1b/Hr) . 225 .175 Heat Exchanger Surface Area (SqFt) 500.0
. Heat Eschanger Overall Conductance 375.0 BTU /SqFt-Hr-F f LThe two pass-correction factor, F= .873 t
l 1
_ _ _ _ _ _ _ _ - - - _ _ .--. _ J
Wr'morvt ; Yankee '1'/4. Core: = - SFP Capaci ty .( Abnormal Heat: Load Calculation)
I Bht;ch - No; Bun-e Decay l Heat- Cumm Heat . Cumm ,-(t . Bun Ts I
tir 368~ 17.95963 17.95963 368- .02 2 92 . 45495. 18.41457 460 1.02
- 3.! s
'92 . 25006 18.66463 '
.552 2. 02 --
- 4 ,
48: . 09587- 18.76049 600 3.02 Assumptions:
,.-Pow'r'per. e Bundle = '15.44197 MBTU/Hr
-Irradiation Tim *e =~ :35040.. Hours
, Reactor. Power =: 1665. MWth:
'/ References;NUREG-0800, Standard Review Plan (1) Section 9.1'.3 Spent Fuel Pool Cooling and Clean-up Systems, Rev. 2
. (2) Branch Technical' Position ASB 9-2 -
Residua 1LDecay Energy for Light-Water Reactors for.Long Term Cooling, Rev. 2 l
l ,
L Spent Fuel Pool Cooling System Service Water System 14 1 ,
.' Outlet Temperatures l(F) 211.39 192.20 - 7 Inlet' Temperatures '(F) 294.77 (Pool Temp) 85.00
- Water Flow' Rates (M1b/Hr) .225 .175 Heat Exchanger Surface Area'(SqFt) 500.0
.= Heat: Exchanger Overall' Conductance 375.O BTU /SqFt-Hr-F The two pass correction' factor, F= .873 I
____________.m.._____......___.__.__m___ m_.____ _ , _